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Alarms and security related schematics 4 Photo-Detector circuit with delayed release and bipolar output 5 Zone alarm circuit 5 Zone Alarm Circuit 5 Zone Alarm System Alarm control keypad Arduino Based Security / Automation Sensors Automatic Intruder Alarm Automatic Intruder Alarm Build an iButton electronic lock based around a AT91C2051 microcontroller (includes ASM source code) Circuit diagram for basic alarm with delayed trigger CMOS single zone intruder alarm Cold activated switch (frost alarm) Combination Lock (PIC16F84) Constructing your own Light Alarm Digital combination lock Digital combination lock using pair of CD4013 CMOS chips Digital Keypad Combination Lock Door Alarm circuit diagram Door knob alarm (PDF) Doorbell for the Deaf Easy to build tripwire activated alarm Electronic door codelock (PIC16F84) Electronic locker digital combination lock circuit diagram Emergency Light & Alarm Emergency Light & Alarm Enhanced 4 Digit Alarm Keypad Enhanced 4 Digit Alarm Keypad Enhanced 5 Digit Alarm Keypad Enhanced 5 Digit Alarm Keypad Everything-that-moves alarm works by inducing eddy currents in living beings Fire alarm circuit diagram based on LDR (light-dependent resistor) Fridge door Alarm Frost alarm Fuse or line monitor that will check the status of up to six fuses including a PCB layout Gate alarm Gate alarm circuit Home security project MC68HC908-based wireless monitoring system is adaptable for use in domestic and industrial settings Micro-power over temperature alarm (PDF) Miniature loop alarm Miniature Loop Alarm Modular Burglar Alarm Modular Burglar Alarm Motorcycle alarm Multi-zone burglar alarm Novel Buzzer Perimeter monitor Proximity detector (uses human body capacitance) Proximity detector for humans / living creatures using eddy current detection Rain alarm / rain detector Refrigerator door alarm Refrigerator Door Alarm RF Alarm RF Pad - combination-controlled, fully customizable radio frequency remote control RFID Access Control System based on an Arduino Single Zone Alarm Single Zone CMOS Alarm Smartcard controlled relay circuit based around Nutchip microcontroller Sun - Up Alarm Touch activated alarm system Transistor based single zone intruder alarm Travel Touch Alarm Ultrasonic radar alarm Ultrasonic Radar Alarm Circuit Diagram Ultrasonic remote control & alarm system Wailing alarm siren Water Activated Alarm Water Activated Alarm Water level alarm Water Level Indicator with alarm Water seepage alarm (PDF) Waterpump Safety Guard for fish pond / fish tank Wire loop alarm Wire Loop Alarm using 4001UBE Quad NOR Gate Wireless alarm FM transmitter module Wireless alarm system based around Nutchip microcontroller Audio power amplifier schematics 10 Watt Audio Amplifier 10 watt audio power amplifier using discrete transistors (includes PCB layout) 100W audio amplifier including PCB layout 100W Guitar Amplifier 100W RMS Amplifier 10-30 watt stereo audio amplifier circuit 110mW emitter follower audio power amplifier 12 dB Amplifier and High Current Line Driver with DC Servo (PDF) 13.5 Watt Power Amplifier using a TL081 opamp and TIP125 / TIP120 power transistors 150W audio amplifier that's cheap to build using TIP142 / TIP147 Darlington power transistors 16 Watt audio amplifier using pair of 8 watt LM383 audio amplifier chips 20 dB Amplifier and High Current Balanced Line Driver 20 Watt Audio Power Amplifier using TDA2005M 20 Watt Class-A Power Amplifier using MJE2955, TIP2955 or TIP36 for output stage 20 Watts per channel stereo power amplifier using LM1875 or TDA2050 power amplifiers 22 Watt Audio Amplifier using TDA1554 two channel audio amp chip 22 Watt Stereo Amplifier using TDA1554 25 Watt MOSFET Audio Amplifier using IRF532 / IRF9532 hexfet transistors for output stage 25W MOSFET audio amplifier 2W Audio Amplifier using BD139 and BD140 transistors 300W Subwoofer Power Amplifier (PCBs available for project) 30W ultra-low distortion audio power amplifier 360W RMS into 8 ohms or 550W RMS into 4 ohm audio power amplifier 4 channel power amplifier with bi-amping and bridging options 50 Watt Amplifier 50W Amplifier 50W audio amplifier using ICL8063 50W audio power amplifier 8 Watt amplifier 8 watt audio amp Ampliefied speaker, built for MP3 player but can be used with other headphone only devices (PDF) Amplified ear for surveillance Amplifier based on LM4780 including a thermal shutdown feature Audio Amp Output Power Limiter Audio amplifier output relay delay Audio amplifier with squelsh-control Basic Audio Amplifier including a SPICE model Build a good Audio Buffer Amplifier Class-A/AB Amplifier delivering 100W into a 4 ohm load Class-C power amplifier CMoy pocket headphone amplifier Compact 50W Integrated Amplifier with Meier Headphone Section Crest Audio LT Series LT100, LT1500 and LT2000 Schematic Set - class D amplifier (PDF) Death of Zen (DoZ) - A New Class-A Power Amp DIY Headphone-Amplifier with Natural Crossfeed DPA 220 amplifier schematic DPA 440 amplifier schematic DPA 880 amplifier schematic Easy to build DIY 50W amplifier based on ICL8063 El-Cheapo - A Really Simple Power Amplifier Five Tube Stereo Amplifier Hammonator Organ to Guitar Amp Conversion (tube amplifier) H-Bridge Power Amp circuit diagram and SPICE simulation files HeadBanger Headphone Amp Headphone amplifier based on 12AX7 tubes Headphone monitor amp Headphone practice amplifier Hi-Fi Headphone Amplifier High quality exponential VCA LM380 2.5 watt audio amplifier circuit Low impedance microphone amplifier Low Power Audio Amp Experiments Low power audio amplifier circuit based on LM386 Low power audio amplifier using BC109C along with BD679 and BD680 Darlington pairs Miniature audio amplifier Mini-MosFet Audio Amplifier More Discrete BJT, Low Power AF Amp Experiments Potpourri of Transistor Audio Amplifier Circuits Quadraphonic Amplifier based on pair of LM1877 devices Ruby is an "enhanced" version of the Little Gem battery-powered amplifier (LM386 based design) Selection of Integrated Circuit Audio Amplifiers Simple 0 to 24 dB Gain Amplifier and Balanced Line Driver (PDF) Simple 200W audio amplifier Simple Class A Amplifier - 10W audio output Single Chip 50 Watt / 8 Ohm Power Amplifier Small audio amplifier based on LM386 Soft-Start Circuit For Power Amps Soft-Start Circuit For Power Amps Spatial Distortion Reduction Headphone Amp Speech Amplifier Box Stereo audio amplifier based on TDA2822M Super linear Headphone amplifier Super Simple 3 Watt Audio Power Amplifier based on TDA1015 TDA2030 8 Watt amplifier Thermo-Fan To Keep Your Amp Cool Tube amplifier Two 9v battery-powered amps based on the LM386. Schematic and PCB/perfboard layouts. Two Transistors Audio Amplifier Variable Amplifier Impedance Voice Amplifier Audio preamp circuits Altec 1564A Preamp Power Supply Altec 428B Microphone Preamplifier schematic API 321 mic preamp schematic Application note showing RIAA phono preamplifier based around the National LM833 (PDF) Audio preamp Audio preamplifier Balanced microphone preamp Basic logarithmic amplifier using op-amp and NPN transistor Basic low frequency preamplifier circuits Bat detector microphone pre-amplifiers Collection of phono preamplifier circuits ECM Mic preamp Electret mic amplifier FET Preamp Cable General purchase audio preamplifier based on pair of 2N2222 transistors Hi Fi preamp Hi-Fi Preamp with remote-control and other advanced features High quality audio preamplifier (OPA2134) IC tone control preamplifier using single 741 opamp Intercom preamp Low impedance microphone amplifier Low Noise Microphone Preamplifier Magentic phono cartridge phono preamp circuit diagram Microphone preamp for portable transceivers Microphone pre-amp with high emphasis Neumann U67 microphone preamp power supply RCA BA-1A two-stage preamp schematic RCA BA-21A preamplifier schematic RCA BA-31A preamplifier schematic Selection of audio preamplifiers including circuits suitable for battery operation Simple Car Preamplifier and Artificial Earth Simple Microphone Preamplifier Simple microphone preamplifier Simple microphone preamplifier Simple transistor preamp - includes a PCB layout Sound card microphone preamplifier Two transistor audio preamplifier with volume control Ultra-Simple Guitar Preamp Vacuum Tube Microphone Preamp Voltage follower with 1G ohm input resistance based on LM11 opamp Automotive, car and motorcycle schematics 12V 300W 4 channel car amplifier schematic diagram 12V battery level indicator for car batteries 12V to 9V car coverter 15W mono car amplifier using TA7227P 20 Segment Expanded Scale Voltmeter including a PCB design 3 Channel, 12 Volt Color Organ for a car 3rd brake light 5301 wideband fuel mixture display 80188XL Engine Tachometer / Race Computer Adaptive Windscreen Wiper Control Authentic Looking Knight Rider Led Project Automatic Headlight Brightness Switch Automatic headlight brightness switch BMW R Series Motorcycle Regulator Schematic Brakelight Flasher Car acceleration meter Car Alarm Arming Horn Beep Canceller Car backup / reversing alarm Car Battery Charger Car battery charger Car battery charger circuit Car Battery Charger, an SCR Design with a 10 Amp rating Car battery voltage tester using LM3914 Car burglar alarm circuit Car Door Keypad Using LIN network Car Nicad charger Car OBD II J1850 PWM, J1850 VPW, ISO-9141 cables schematic pinout Car OBDII diagnostic interface cable schematic pinout Car power supply unit for digital projects, small car PCs etc Car Timer with Atmel ATiny45 to automatically turn of accessories to prevent flat battery Combination lock for car liftgate Common Ground for Older VPW OBD Circuit Custom USB tyre pressure monitoring system Digital speedometer for cars with 7-segment display of speed Economy radar detector Electronic car ignition circuit Engine control unit schematics FCD (Fuel Cut Defencer) Flashing / pulsing third brake like for cars Flashing light / emergency beacon for vehicle Fuel injector pulse width monitor Grand Cherokee Off-Highway Lights Headlight flasher Headlight guard Headlight reminder Headlight timer Hijack alarm Interface between GM's 5 Volt 8192 baud ALDL data stream and a PC serial port Interior light extender KITT (from Knight Rider) Car scanner using incandescant lamps Large capacitor charge "controllers" (Car Audio) Low battery cut-off circuit for a car or truck Motorctcle turning signal system Motorcycle battery charger Motorcycle brake light flasher Motorcycle low battery voltage warning circuit Network car controller provides functions for remote door locks, headlight reminder, and car finder Opendiag OBD-II Schematics & PCB Layout Opendiag OBD-II Schematics & PCB Layout Parking aid senses distance to rear of vehicle Portable CD Player Adapter For Car Portable CD Player Adapter For Car Pseudo car alarm system Seatbelt reminder circuit Simple car battery charger Simple car battery voltage monitor Simple Car Preamplifier and Artificial Earth Simple Vehicle Loop Detector (inductive loop for driveway etc) Speed alert - wireless portable unit Synchronized multi-spark module (SMSM) for Electronic Ignition Devices (EID) Third brake light pulser circuit Two LED trouble light system Ultrasonic parking sonar electronic circuit diagram using transistors and 4000 series CMOS Vehicle Telemetry Platform based on an Arduino Volvo 164 electric fan thermostat Wide Band Fuel Mixture Display Wiper Speed Control Wireless Auto Tachometer Wireless Auto Tachometer Data acquisition (DAQ) and data logging schematics 1-Wire Barometer Project 4 Bit Digitizer / flash ADC using discrete components 8 Photo-Detector Circuit Board A PIC Based Temperature Data Logger Acceleration Sensor Network Accelerometer Schematic Accelerometer with microcontroller and display ADC Input Driver DIFFERENTIAL to DIFFERENTIAL ADC Input Driver DIFFERENTIAL to SINGLE-ENDED ADC Input Driver FULLY DIFFERENTIAL AMPLIFIER ADC Input Driver SINGLE-ENDED to DIFFERENTIAL ADC Input Driver SINGLE-ENDED to SINGLE-ENDED ADC logger 6ch Measurent and serial port logger with wireless longrange link Addressable ADC ADXL202 break-out board Amplifier for the AXUV Series Photodiodes Analog input section based on AD9220 Arduino based water flow guage Atmel Mega32 8ch Analog signal measure logger Capacitance type liquid level measurement (PDF) Centronics port D/A converters and low-pass filter Circuit monitoring device logs for over 10 days and can log up to 32k events both digital and analog Connect a NTC with a wheatstone bridge to a normal AD-Input Data Acquisition & Logging System Using AT89c51 and Visual Basic Data Acquisition System using ATmega8 Data Acquisition System using ATmega8 Home Brew Compass Sensor Honey Bee counter (PDF) Low cost gyro / accelerometer combo sensor Making an LM35 temperature recorder (based on PIC12F675) - logs to EEPROM Making an LM35 temperature recorder (based on PIC12F675) - serial output Online thermometer based on an Arduino PIC16F877A Thermometer with MCP9700A sensor Precision Digital Altimeter Pressure Sensor-Based Altimeter Circuit Pyranometer to Current Converter Rain detector Remote digital thermometer sends data over AC power line Self made data-logger V2.5 (second edition) Serial interface (RS232) I/O card suitable for data acquisition Serial Port A/D-converter Simple Analog to Digital Converter using ADC0808 that displays output using LEDs Simple device for connecting serial instrument with RS485 or RS232 to the internet Simple RS422 Converter for Minilogger Strain gauge sensor interface Temperature compensated logarithmic amplifier (PDF) includes circuit and design notes Thermostat node schematic Transducer Amplifiers Ultrasonic Range Finder & Imager Ultrasonic range finder circuit USB datalogger - simple-to-use, long-term measurement solution Using a 555 Timer as an A/D converter Voltage follower with 1G ohm input resistance Water Tank Depth Sensor based on an Arduino Water-level sensor Weather Station Receiver based on an Arduino and 433MHz RF receiver module Wind speed logger Wind speed logger Mk2 Wireless Liquid Level Sensing for Restaurant Applications Wireless weater station XL-DIG 3-axis Accelerometer board - 3-axis digital I2C/SPI accelerometer board Filter schematics "A" Weighting Filter For Audio Measurements 136KHz bridged-T notch filter to reduce strength of the German utility station DCF39 on 138.83 kHz 1KHz 4th order Butterworth filter using LT1367 quad operational amplifier 29.85 MHZ bandpass filter schematic 29.85 MHZ notch filter schematic 3 KHz low pass filter plus audio amplifier circuit diagram 3KHz low-pass filter plus audio amp (PDF) 440 Hertz Peaked Low Pass Audio Filter Experiments 45 to 90Hz hum filter 4th Order Butterworth filter schematic and calculator 'A' Weighting Filter For Audio Measurements Active bandpass filter with TDA2320A Active bandpass filters Analog Filters for Data Conversion (ADC filter) A-weighting filter from an old Ampex service manual Bandpass and IF Filter Circuits Bandpass filters Biquad Active Bandpass Filter Schematic Chebyshev / Butterworth filters Chebyshev low pass filter, rolls of at 30MHz Collection of quartz crystal ladder filter circuit diagrams CW Filters Design of active filters with operational amplifiers (includes circuit and Java filter calculator) Digital signal processor (DSP) for radio communications Discrete Component Audio-Frequency RC Filters Filter Circuit for the Earthworm Seismic Data Acquisition System Filters for the RadioJove Receiver Fourth order Butterworth BPF circuit diagram and design notes Galaxy Noise Filter Higher Order Analog Butterworth Filter Designs, includes on-line filter calculator LC filter design on-line calculator Low pass filter for subwoofer Low-pass active filter Matching Low Pass Filter for 136kHz transmitter Multiple Feedback Bandpass Filter Multiple Feedback Bandpass Filter RC Low-Pass Filter with Op Amp Buffer (single pole filter) with SPICE simulation files Sallen-Key Active Butterworth High Pass Filter Calculator and circuit diagram Sallen-Key Active Butterworth Low Pass Filter Calculator and circuit diagram Sallen-Key Low Pass Filter Calculator (handles Butterworth filters, Bessel filters and Chebychev) Sallen-Key Low-Pass Filter (Double-Pole) with SPICE simulation files Self-tuning CW filter Series Notch Fliter Designer / Calculator (displays circuit diagram after calculation) SSB AF filter Variable notch filter with both high and low pass filters Games and fun stuff (electronic schematics) 3-up decision maker Archery timer Atari Punk Console schematics Battery Meter for Pinball Machines Burger Time Arcade Game circuit diagram (PDF) Cat toy using a PIC12F675 and a small weighted motor to keep your cat amused Coin tosser Decision maker Dig Dug Arcade Game (800k ZIP) DIY flying saucer / UFO using a PIC microcontroller DIY shutterglasses controller Dreamcast interface Dreamcast PC serial adapter Dual LED dice (available in kit form) E.S.P. Conjuring Trick Electronic Astrologer (decision maker) Electronic dice Electronic Nicad glow plug driver Electronic roulette wheel circuit diagram Flashing heart Frogger Arcade Game circuit diagram (PDF) Furby Resurrection - Project that replaces the electronics in a Furby with new custom electronics Furby reverse-engineered circuit Fuzebox - open source 8-bit game console based on Atmel ATmega644-20PU Galaga Arcade Game circuit diagram (PDF) Game Show Timers Gyrus Arcade Game circuit diagram (PDF) How to install LED lights to Mini-Z model car (based on PIC12C509) How to use a SCART TV as a Monitor for MAME arcade game emulator Interfacing Sony control stick to Empeg JAM(Just A Minute) Quiz Game Circuit Jeopardy game circuit diagram using three CMOS logic chips Judge Dredd pinball locking ring modification Junior Pacman Arcade Game circuit diagram (PDF) Ladybug Arcade Game circuit diagram (PDF) LED Dice implemented with a PIC microprocessor LED dice project based on 555 timer and CD4017 decade counter LED dice project including nice veroboard layout (PDF) LED dice using PIC16F88 LED dice with fast roll Lego Mindstoms IR Link PIC transceiver Lego Mindstorms Double Rotation Sensor Low-cost bingo game for a TV based on an Atmel microcontoller Magic Wand Conjuring Trick Mappy Arcade Game circuit diagram (PDF) MBC5/CPLD for the GameBoy MemoSound game based on a PIC16F84A Moon Cresta Arcade circuit diagram (PDF) Mr.Do Arcade Game circuit diagram (PDF) Multi-User Jeopardy Game (Fastest Finger First) PacLand Arcade Game circuit diagram (PDF) Pengo Arcade Game circuit diagram (PDF) Persistance of vision (POV) toy PIC10F200-based electronic dice PIC16F84-based video game system Pine Racecar Victory Judge Pine Racecar Victory Judge Q*Bert Arcade Game circuit diagram (PDF) Qix Arcade Game circuit diagram (PDF) Quiz game circuit Quiz show indicator Reaction timer using 4013 flip-flop and 4060 12-stage binary ripple counter Reflex Action Game Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989 Scramble Arcade Game circuit diagram (PDF) Single LED dice kit circuit diagram Space invaders game using PIC microcontroller SRX1 (Stephane's Robotic eXperiment 1) SX28-based color video game system Talking Egyption frog box Time Pilot'84 Arcade Game circuit diagram (PDF) Two player quiz master game VCR ping pong game Video ping pong game Virtual Game System - A game console with a mechanically scanned display Visor cradle serial interface Xevious Arcade Game circuit diagram (PDF) Infrared based schematics 40khz IR Tester 40KHz light receiver (PDF) 40KHz TV-VCR repeater (PDF) 50MHz Receiver for the IR Detector 50MHz Transmitter for the IR detector 555 timer 40khz IR Oscillator Basic infrared link for audio communication over distances up to 3 metres Build an Infrared night scope Computerized Infrared Remote Decoding IR Remote Controls Digibox interface Direction sensing infrared motion detector using PIR (PDF) DVD thermometer - display temperature on TV by remotely controlling DVD player by infrared Fire-Stick infrared remote control High power infrared remote control to turn off television sets from a distance Implementing Infrared Object Detection Improved infrared receiver for PC with status LED Inexpensive infrared reflectometer Infa-Red Remote Control Infra Red Switch Infra Red wired Repeater circuit to control appliances from a remote location Infrared / Ultrasonic beacon Infrared beam barrier / proximity detector Infrared beam door alarm Infrared Body Sensing Infrared circuits for remote control Infrared gate (door entry alarm) Infrared gate for door Infrared Head Phones Infrared headphone system (includes transmistter and receiver schematics along with vero layout) Infrared lamp Infrared level detector for liquid level detection and proximity detection Infra-red Light Barrier Using 555 Infrared link for 10-BASE-T / 100-BASE-T PC network card Infrared motion detector circuit Infrared Motion Detector using a PIR sensor (PDF) Infrared object detector using a PIC12F629 microcontroller Infrared proximity detector based on Microchip PIC12C508 or PIC12C509 Infrared Proximity Detector based on Vishay TSOP4830 Infrared Receiver Module Schematics Infrared remote control tester using a SFH2030 photodiode and a CA3140 operational amplifier Infrared remote transponder Infrared S/PDIF Receiver Infra-Red Sensor/Monitor Infrared switch using any infrared remote control Infrared transmitter for locomotives Infrared Transmitter Project Implemented on a Solderless Breadboard IR detector IR detector IR detector / emitter IR illuminator for night-vision tv cameras and scopes IR Link IR remote control IR remote control extender IR Remote Control Extender Circuit IR Remote Control Extender Circuit (Mark 2) IR Remote Control Extender Circuit (Mark 3) IR Remote Control Jammer IR remote control tester IR remote control tester IR wheel encoder board iRDA transceiver to extend IR port range up to 15 meters IR-related ASCII Schematics V1.00 Measuring the speed of light with an infrared LED / photodiode (TDOA) Micro based PIR to IR remote converter PC IR Remote Control Hardware Project to capture infrared remote control signals and play them back, based on Atmel ATMEGA48 micro Pyroelectric Infrared (PIR) Sensor RC5 Repeater to extend distance of infrared remote controls Remote control uses an IR receiver chip to receive the IR signal from the remote Remote infrared terminal for projects requiring IR communications Serial port controller infrared transmitter (PIC16F628) Simple Infa-Red Remote Control Simple infra-red detector Simple infrared remote control Simple IR transmitter circuit Simple on-off IR photoswitch without use of comparators Simple Remote control Tester TV remote control Blocker Universal Serial Infrared Receiver Wireless IR headphone receiver Wireless IR headphone transmitter LASER related power supplies and data transmission 20MHz laser light detector (PDF) 20MHz VCSEL 3mW laser test circuit (PDF) 40KHz laser burst detector (PDF) Circuit for temperature stabilisation of laser diodes Circuit to measure speed of light with nanosecond pulsed 650 nm laser diode Circuits for biasing and modulating laser diodes Diode laser electronic circuits for atom optics Experimental laser data link Guide to Building a Homemade XY Scanner Heathkit modulated HeNe laser power supply kit (HK-HI1) HeNe laser power supply Home Built Laser Projector Laser beam alarm system Laser diode transmitter RF section Laser high-voltage power supply Laser light output intensity meter Laser link communicator project from Electronics Australia magazine Laser Listening Device Laser Modem with an Arduino Microcontroller LASER Power Supply Laser power supply Laser range finder and reflectivity meter for the MARS-96 international space project (PDF) Laser rangefinder using a linear image sensor Laser Target Finder Sensor LASER Transmitter/Receiver Laser transmitter/receiver LASER Transmitter/Receiver using Pulse Width Modulator (PWM) for 12V / 24V applications LASER/LED light output intensity meter (PDF) Low Cost Scanning Laser Rangefinder (PDF) Low noise PIN diode laser receiver circuit Micro-Laser range finder Micro-power 40KHz burst laser diode driver (PDF) Modulated laser diode tester (PDF) OPT301 Laser receiver Pulse Circuits for Infrared LEDs and Visible Diode Lasers Rangefinder with Fast Multiple Range Capability Real-time Laser Range Finding Vision System RS-232 Laser Transceiver RS-232 laser transceiver Simple high current pulsed laser driver using an avalanche transistor Simple laser communicator Simple LASER Transmitter/Receiver using HeNe laser tube Sniper tag laser beam detector LED related schematics "Mini-Beacon" miniature programmable LED Flasher that is based around a PIC12F629 microcontroller "Peggy" - A Light Emitting Pegboard Display 1.5V LED flasher A (PDF) 1.5V LED flasher B (PDF) 10, 8 And 6 Step LED Circuits (CD4017) 12 Volt Knight Rider LED display 13 Color LED Rainbow 13 Color LED Rainbow 18 LED dimmable LED lamp 3V LED chaser using 4017 60 LED Clock 6V ultra-bright LED chaser using 74HC4017 7 Segment LED Counter 7 Segment LED Counter A "persistence of vision display" (POV display) using LEDs Adjustable flashing LED Alphanumeric Led Display Project Assorted LED circuits Automatic LED display dimmer using a LED as a light sensor AVR Color Clock using RGB LEDs Bedazzler: Do-it-yourself Handheld LED-Incapacitator (non-lethal weapon) Bicycle LED POV (persistence of vision display) LED display Bicycle rear flashing LED light Big 7-segment LED display board with SPI interface Christmas Star Christmas tree Color fade Colour Shifting For Bi-Colour LED's Current Regulators For Light Emitting Diodes Dancing LEDs Digital Up / Down Counter with 7-segment display Discrete LED Color Organ Driving led display matrix from a PIC micro Fading LEDs Fantastic Atom Expander Flashing LED advertising badge (PDF) Flashing LED advertising badge (PDF) Flashing LED circuit using 555 timer Fun with LEDs - a variety of LED flahser projects Giant T-shaped LED matrix display board for financial applications containing 275 8x8 LED modules Heart of LEDs High Current Pulsed LED High Efficiency 12V White LED Driver High power LED driver using LTC3780 How to Control LED Brightness with a PWM Circuit using a 74AC14 Incandescent LED Circuit Knight rider scanning LED lights LED Audio VU Meter LED Chaser LED chaser LED Chaser using 4011 / 4017 CMOS chips LED color fade LED dimmer circuit Led display digital Voltmeter LED flasher using 4584 hex inverting Schmitt trigger LED flasher with "Rising and Falling" Brightness LED Modulation Circuits including 5MHz and 50MHz versions LED Mood Light LED Mood Light LED Running Message Display using CD4017 with transistor drivers rather than a CPU LED Thermometer LED Voltage Indicator Board LEDMATRIX, a 80x32 pixel DIY LED matrix display Linear constant current source dimmer for a white 24-LED array Little bike light using LEDs LM3909 replacement using discrete components Low battery voltage flasher (PDF) Low current LED flasher (PDF) Making an Amplified Color Sensor from an LED and an Op Amp Notes on using LEDs and various LED driver circuit diagrams Persistence of Vision Display for Bikes Pocket Ignignokt LED display PointLess LED Array - A 8 by 8 array displays something using POV POV Persistence Of Vision 2 x 32 LED display Pulsed LED test circuit (PDF) Regulated Dual White LED Lamp Running Message Display SAA1064 display module project Schematic and breadboard layout for reversed LED color sensor using an opamp Scrolling LED sign based on Atmel ATtiny2313 AVR microcontrolle Selecting of LED projects including a flashing Christmas tree Sequential flashing arrow circuit using a 4017, also includes a PCB layout Seven Component Regulated LED Lamp Seven Component Regulated LED Lamp Simple current limiting for LED flashlights Simplest LED Flasher Circuit using a 2N2222 transistor Simplest LED Flasher Circuit led Single and Two Cell White LED Drivers Without Inductors Single cell LED flasher with two-year battery life (LM3909 replacement) SPI Interface Big 7-Seg LED Tiny micro-controller driven lightshow using LEDs and a Picaxe 18A (PDF) Using Common Cathode Or Anode LEDs As Bipolar LEDs Various LM555 LED Blinker Circuits White LED circuits White LED Drive Circuit White LED Lamp White LED Stroboscope YoYo enhancement device using a PIC12F629 to provide LED lighting effects Lighting and light controller schematics 12 Volt DC Fluorescent Lamp Driver 12 Volt Strobe, Coil Driven 1200 Watt Lamp Dimmer Circuit using Q4015LT combination Diac 12V stroboscope 12VDC Fluorescent Lamp Driver 12VDC Fluorescent Lamp Driver 12VDC Fluorescent Lamp Driver 1W Fluorescent lamp night light (PDF) 220 Volts Flashing Lamps 4-channel dimmer rack 5W Fluorescent light intensity modulator (PDF) 6 Channel Auto Reverse Sequential Disco Running Lights Adjustable Strobe Light Adjustable Strobe Light Adjustable Strobe Light Automated crib light Automatic Room Lights Automatic Staircase Light 1 Automatic Staircase Light 2 Battery juicer provides a night light from almost flat batteries that would otherwise be discharded Battery-powered Night Lamp Bicycle back Safety Light Bike Light Flasher Black Light Black Light powered by a 6 volt battery Brightness Control for small Lamps Candle simulator based on a PIC12F675 microcontroller Christmas lights tester Circuit for remote lighting controller using a 433MHz AM keyfob transmitter Circuit to enable cycling a string of Christmas lights Courtesy Light Digitally Addressable DALI Dimming Ballast (PDF) Dimmable Li-Ion Halogen Bike Light Diode Type Constant Lighting Circuits Disco light controller (ZIP file) DMX lighting and special effects Easy Xenon DC-DC Converter using LM386 Electronic candle Electronic night light Emergency light flasher schematic Flashing neon christmas lights Flashy Christmas Lights Fluorescent Tube "Strip light" Driver Inverter for fluorescent lights as published in Silicon Chip Magazine February 1991 (PDF) Lamp flasher/dimmer LED Mood Light LEDs or Lamps Sequencer is versatile modular design with no limits on number of lights Lightning bulb - Create an electrical storm in a light bulb Low-voltage light dimmer LX-800 Lighting system Mini emergency light Neon desklamp Neon lamp dimmer Night light saver using AT89C2051 RHINO8 EL Sequencer Strobe light Strobo Disco Light Using Standard Tube Lamp (TL) Traffic light controller using an Arduino microcontroller TRIAC based lamp dimmer circuit diagram TRIAC Light Dimmer TRIAC Light Dimmer TRIAC light dimmer Xenon Flash Indicator (XFI) Xenon Strobe Light Medical and health related schematics "TENS" Circuit diagram for muscle stimulation Automated Timestamp for Computed Radiography Brain-Wave Machine Cardiac monitor Cranial Electrotherapy Stimulation (CES) circuit diagram Digital pedometer circuit ECG amplifier with right leg drive ECG Measurement and Analysis EKG/EEG circuit Electronic Stethoscope Electronic Stethoscope Galvanic Skin Response (GSR) Circuit Heart rate sensor Heartbeat transducer using infrared LED / detector Jogging timer Lie detector Model 2030 XRAY monitor instruction manual including schematics (PDF) Muscular Bio-Stimulator Muscular Bio-Stimulator using 555 timer OpenEEG open hardware EEG project Optical Heart Rate Monitor PC based biofeedback monitor Photodiode Pulse Detector - using infrared light to detect a heartbeat (PDF) Portable blood pressure monitor Positive Feedback Circuit for Isometric Muscle Experiments Pulse rate monitor / telephone based electronic stethoscope design Salt taster - detects the amount of salt contained in liquid foods Simple lie detector Simple lie detector Sleeping aid based on electromagnetic-field radiation Snore alarm electronic device Tan timer to prevent sunburn The ESP SIM (Sound Impairment Monitor) Tiny EEG interface schematic Wireless Electrocardiogram Monitor Microcontroller based schematics "Singing" Christmas tree based on Microchip PIC16F84 (E)EProm, PIC and GAL Programmer 10 tricks for interfacing to the PIC16C508 10 tricks for interfacing to the PIC16C508 101 AT Keyboard to ASCII Decoder using 68HC705J1A MCU 128x64 LCD Driver for AT90S2313 (ZIP file) 2-wire LCD interface using PIC16CF84 3-wire serial LCD interface for the PIC 40+ MHz 5-digit frequency counter with an AVR 2313 4-Channel Timer using Atmel 89C4051 and MAX7219 display driver 50 MHz frequency counter, voltage meter & SWR/PWR indicator 6802 Nano computer 8049 Spy - read the internal ROM contents of a 8048 or 8049 processor 8051 Development System Circuit Board 8051 Development System Circuit Board 8051 Development System Circuit Board 8051 Development System Circuit Board 8051 SBC (single board computer) 8051SBC V1.1 8088 maximum mode SBC 80C31 stepper motor controller 89C2051 microcontroller programmer 89S52 Project Board 90S2313 AVR Robot Board A PIC16F819 Dymoclock (also demonstrates interfacing 30 LEDs to a PIC using only six I/O pins) A PIC16F84A Alarm Clock A PIC-based "TDOA" RDF (radio direction finder) antenna unit A Real Time Clock IC (DS1307) project using the PIC micro A Scenix (and PIC) Programmer A Voice Controlled LED Light Show using a VRStamp Acceleration monitor using ADXL202 and AVR ADC conversion using ADC0804LCN and 8051 AFSK 1200 Modem based on PIC16C620 'Almost No Parts' 7-segments 12/24 Hours LED clock with PIC 16F84A or 16F628A Analog datalogger based on T89C51RD2 Analog to digital (ADC) conversion notes Arduino based controller interface for servo motors, stepper motors and DC motors Arduino microcontroller prototyping system Arduino speech sythesizer Asynchronous 40-bit TTL CPU AT89C2051 Digital thermometer and clock AT89C2051 line-follower robot AT89C2051 Night light saver AT89C2051 real-time controller AT89C2051 serial COMs to LED driver AT89C2051/4051 Driving dot LED AT89C2051/4051 Easy-Downloader AT89C2051/4051connecting dumb terminal AT89C2051/4051scanning 7-segment display and keypad AT89C2051/4051stepper motor interface AT89C51/52/55 Easy-Downloader AT89Sxx Cheap and Simple Learning Board AT90S8515 experimenter board ATmega48 based Nixie Clock ATmega8 based TNC with GPS and WX support Atmel 8051 Flash Based-Microcontroller Programmer Atmel 89 Series Device Programmer Atmel 89C Series Flash Microcontroller Programmer Atmel 89C2051 In-Circuit Programmer Schematic Atmel 89C2051 prototype board Atmel 89S and AVR Programmer (STK200) Atmel 90s2313 based TNC Atmel AT90USB development board Atmel ATmega128 development board Atmel ATtiny26 development board Atmel AVR 90s2313 based POCSAG encoder (ZIP file) Atmel AVR and 8051 series ISP programmer Atmel AVR ATMega 8535/16/32 and AT89S5x family learning kit Atmel AVR ATtiny45 development board Atmel Mega88 Dual Temperatur meter Atmel Mega88 Temperatur meter, Type K sensor, Heat set and regulator Atmel Microcontroller based Ultrasonic Ranger Automatic door opener with PIC12C508 AVR STK200/STK300 ISP Dongle circuit diagram AVR Thermometer AVR thermometer / thermostat based on an Atmel ATtiny2313 AVR910 - AVR Programmer AVR-Based Serial Port IR Receiver AVR-Core V1.1 - DIP-like development board for ATmega128 processors (PDF) AVRlinx V1.1 - Development board for ATmega16, ATmega32 processors with data radio transceiver (PDF) AVRmini V2.0 - Development board for all AVR processors in 40-pin packages (PDF) AVRmini V3.1 - Development board supporting all AVR processors in 40-pin and 64-pin packages (PDF) AVRmini V4.0 - Development board with Ethernet/USB for 40-pin AVR processors (PDF) AVRmini8 V1.0 - Development board for ATmega8, ATmega44, ATmega88, ATmega168 processors (PDF) Basic Stamp based altimeter Build a PIC controlled DDS VFO, 0 to 6 MHz C-52 EVB Robot Controller CASIO datalogger system based around Microchip PIC microcontroller CF/IDE Adapter V1.0 - CompactFlash and IDE interface for your microcontroller Cheap Ultrasonic Range Finder based on a PIC microcontroller Cheap Ultrasonic Range Finder based on PIC16F877A with a 8MHz crystal Circuit for interfacing an Arduina to USB using an FTDI FT232BM chip Circuits for interfacing microcontrollers to a wide number of real-word interfaces Complete Design for Giant 8-foot LCD Counter (Zip file) Connecting AT90S2313 with LCD display 2x16 char and 4x4 keypad Connecting LED to PIC Micro I/O pins (PDF) Cypress PSoC based digital wallet to record secret codes and passwords securely Darkroom timer using PIC16F84A Designing a 4-Channel A/D (ADC) converter with the PIC12C671 Digital compass using PIC16F84 Dirt cheap video using a PIC16F819 microcontroller Driving high-power loads with a microprocessor DS1820 Arbiter V2.00 Schematic EasyPic2 with on-board Ethernet Adapter Electronic distance meter based on Motorola 68HC908QY4 Electronic irrigation controller based on PIC Electronic safety lock based on ATtiny26 Ethernet shield for Arduino (Xport) EZ80 single board computer schematic (Z80) Fan timer based on Motorola 68HC908QT2 Galvanic decoupling of I2C bus GPS / Datalogging shield for Arduino microcontroller GPS LCD Display Project Hardware Random Number Generator with an SX microcontroller Homebrew Basic Stamp project I2C LCD interface Iambic keyer based on a PIC16F84 or PIC16C84 IDE interface to a Microchip PIC16F877 microcontroller In-Circuit PIC Loader (ISP programmer) over parallel port Interfacing an LCD touch control panel to an Arduino Interfacing DRAM to AT90S8515 Interfacing EEPROM to a Basic Stamp Interfacing the MAX186 8 Channel ADC to the BSII Interfacing the MAX187 ADC to the BSII to measure voltages Interfacing the PIC16C508 IR On/Off Switch Using a PIC12F629 Microcontroller Isolated RS232 for PIC16F84 Isolated RS232C for PIC16F84 or other microcontrollers JDM programmer Jupiter card programemr KD7LMO Micro Beacon (PIC18F252) LCD clock based on AVR Attiny2313 LCD thermometer using PIC16F871 LCD to PIC16C54 schematic LED 5x7 display using a PIC microcontroller Linuxstamp general purpose processor module based on Atmel AT91RM9200 Long-period watchdog timer Low cost Atmel in-system programmer Mains clock controller using AT89C2051 Measuring Acceleration Using a PIC Microcontroller (ADXL202 + PIC16F84A) Microchip PIC ICD (in-circuit debugger) Microcontroller sensor and actuator interfaces Microprocessor RS-232 Reset Microprocessor using Xilinx FPGA MiniLOGGER V1.0 MMC to PIC16F876 circuit diagram Motorola 68HC11 evaluation board Motorola 68K SBC (single board computer) MTK-85 8085 Microprocessor Training Kit MTK-85 8085 Microprocessor Training Kit Multi PIC Programmer 5 Ver.2 Multi-chip programmer Night light saver (PIC12C508) Nixie clock (PIC16F876) Parallel AVR programmer PC to microcontroller communications using power from the PC serial port PIC 18 programmer (PIC18F458, PIC18F452, PIC18C252, PIC16C745, PIC18F6620, PIC18F6720) PIC based packet radio encoder (PDF over FTP) PIC based touch clock that demonstrates interfacing a PIC microcontroller to an LCD touch panel PIC demo board PIC ICD PIC LCD and Keypad driver PIC Light Chaser using PIC16C84 PIC micro LED projects PIC micro multiple servo motor interface PIC micro programmer PIC micro programmer that runs under MAC, Win98, XP, Vista, DOS, Linux, etc PIC micro to ISA bus interface PIC microcontroller servo motor interface PIC Project #1 - RS232 to I2C Interface PIC serial communications tutorial, includes circuit diagram and PIC16F84 assembler code PIC Serial LCD project - An RS232 serial LCD interface using a standard HD44780 LCD PIC sonar (ultrasonic) range finding project with seven segment display using PIC micro PIC vacuum fluorescent display (VFD) interface PIC Web Server Schematic PIC12C508 Night-light saver PIC12C508 Phase Controller for 2kW heater (ZIP file) PIC12C509 Gym Timer (ZIP file) PIC12C509 logic gate replacement for nitrogen filler (ZIP file) PIC16 DemoKit3 with programmer and displays PIC16C505 IR / wireless remote control PIC16F628 controlled FLL (Frequency Locked Loop) VFO for HF (PDF) PIC16F84 Based Morse Code Reader PIC16F84 CW decoder (PDF) PIC16F84 debugging terminal PIC16F84 LED chaser PIC16F84 line following robot PIC16F84 miniature real-time controller PIC16F84 programmer PIC16F84 pulse monitor with date/time output (ZIP) PIC16F84 Serial I/O-expander with PicBasic PIC16F84 tone generator PIC16F84 tone generator (6-Bit) PIC16F84 tone generator with source code PIC16F84 TRIAC / IGBT brightness phase controller PIC16F876 Datalogger PIC16F877 Programmer And Development System PIC16F877 to IDE interface PIC18F2550 Project Board PIC18F4550 Development Board including PCB layout suitable for home etching PICADC - a free, PIC based "intelligent" A/D converter PicCon - Hidden Radio Transmitter Controller PicoWeb V5.1 (AT90S8515) tiny web server PIC-Programmer 2 PIC-Programmer 2 for PIC16C84 etc PIXpand - TI calculator to Playstation memory card interface POCSAG encoder/decoder (Zip file) Poor man's analog to digital converter (ADC) using a 2N222 transistor and a few passives (PDF) Programmer PIC16F84,12C50x and EEPROM 24Cxx Programming hardware and softrware for 14-bit FLASH PIC microcontrollers PS/2 keyboard keystroke logger based on Atmel 89C2051 RF remote control based on Basic Stamp Rotating Sprocket Wheel Generator (PIC16F84) RS232 interfaced DVM using a PIC12F675 including source code for CCS C Compiler RS-232 to TTL Translator RS485-like multi-drop bus with half duplex serial protocol ScanMate audio activated recorded Scriptable thermometer / thermometric controller based around a COP8-CCR9-PLC44 microcontroller SD card interface for PIC microcontroller including schematic and source code Serial LCD controller using a PIC16F628 Serial LCD Controller using Microchip PIC16F628 Serial port I/O interface using AVR microcontroller Serial to parallel converter using the AT89C2051 Serial-based PIC16F84 Programmer For Windows 95/98/NT/2000/ME/XP Ser-Key 10-Key Serial Keypad Encoder Several Atmel AVR programmer circuits Simple 10 bit DAC for the Arduino using TLC274 opamp Simple CW Keyer based on Atmel ATtiny 2313 Simple QRSS callsign keyer based on an Atmega AVR programmed in C Simple RS232C Level Converter using Transistors Smart card programmer Solderless Breadboard Arduino Clone for Arduino prototyping Speech recognition using HM2007 Speech Synthesizer Development System using a PIC microcontroller SPI Flash Microcontroller Programmer SPI2CF, a fast and efficient WLAN interface for the AVR T89V51CC01 Development board Tachometer Measures Very Low Frequencies (PIC16F872) Talking fish hack using a PIC16F819 microcontroller Talking PIC - based on SP0256 TekBots universal device programmer with USB interface Temperature controlled based on AT89CX051 Temperature monitor/controller: AVR 2313 / DS1621 Tiny 2313 Project Development Board Tiny 2313 Project Development Board Tiny Eprom Simulator Tony Nixons Pocket Programmer (PIC) Touch senstor based on Atmel AT90S2313 TTL to RS232 adapter using 2N3906 / 2N3904 transistors Ultra low-cost programmer for AT90S family Ultrasonic Distance Measurement With the MSP430 (PDF) Ultrasonic Distance Measurer based on Freescale MC9RS08KA2 (PDF) USB and GLCD expansion board for 8051 SBC USBmini V1.0 - Generic USB Full-speed interface board (PDF) USBtinyISP - AVR programmer & SPI interface project Using an ADXL330 accelerometer with an AVR microcontroller Using the AT89C4051 as a RTC (real-time clock) Variety of circuits for RS232 to TTL Signal Conversion Variety of circuits for TTL to RS232 Signal Conversion Victoria TAFE programmer (based on AT89C2051) Wave (Audio) shield for Arduino microcontroller Wireless communications using a Basic Stamp and low-cost wireless data modules Wisp628 ISP Microchip PIC Programmer WLoader - PIC16F877 application loader / bootloader Misc audio (also see Music, Amplifiers, Preamp) "Anti-RIAA" Equalizer for Line to Mag Phono Converter (PDF) 1 Watt audio amp using a TDA7052 12 watt audio amplifier with tone using TDA1020 3 Channel Spectrum Analyzer -30dBm to +30dBm Audio Level Meter 3-Band audio graphic equalizer 4 channel audio selector 5 watt audio amplifier using TDA1010 6-Input mixer Acoustic Simulator for Headphone Amplifiers Active Sub-Woofer and Controller Actvie speaker based on a dual op-amp (LM833) and TDA2030 power amp Additional RFI protection for line input circuit diagram (PDF) Amplifier thermal protection An Audio Limiter for NBFM use An Audio-Noise-Based Voting Circuit Analog Synth Keyboard Schematic Assortment of Siren Circuits Audio DAC3 (SPDIF->Analog Audio) Audio Detector Circuit Audio graphic equaliser Audio Indicator - monitor a loudspeaker, alarm, or audio source for presence of an audio waveform Audio line isolator Audio mixer (ASCII circuit diagram) Audio Signal Source Audio Spectrum Analyzer and Equalizer Designs Audio Speech Processor Audio VU Meter based on pair of LM324 quad opamps Automatic Charger for Battery Operated Hi-Fi Preamps Automatic loudness control Balanced Line Driver & Receiver Base / treble control circuit using LM1036N Bass booster using a TL702 opamp Bass EQ pre-amp correction for high impedance ceramic crystal pickup Beat Tracking Strobe Better Volume (and Balance) control circuit diagrams Big Ben sound effects generator Bridging Adapter For Audio Power Amplifiers Bridging Adapter For Power Amplifiers Build a Tape Linearizer and a Distortion Analyzer Cicuit diagram for super long range microphone for use with a shotgun microphone or parabolic dish Clack Clack Electronic Bell CMOS IC 1 kHz Audio Oscillator Condenser microphone hookup Cuckoo sound generator Cuckoo sound Generator DC Fault Protection Circuit for Audio Amplifiers Defeating SCMS on DAY recorders using a Sony CXD2601 chip Digital Delay Unit For Surround Sound Digital noise generator (PDF) Digital volume control Digital volume control Digital Volume Control based around CD4067 CMOS chips Digital Volume Control using DS1669 Digital Pot IC Digital Volume Control using DS1669 Direct Injection Box for Recording & PA Systems Doorphone intercom Dual Voltage Controlled Oscillator w/Modulator Dynamic microphone to electret microphone input Electret microphone powering circuits Electronic attenuator Electronic Canary Electronic canary sound effects Electronic siren Envelope generator ADSR Fast Audio Peak Limiter FET Audio Mixer FET audio mixer Guitar Reverb Effect Version 2 High CMRR Balanced Interface for Crystal 18 or 20 Bit A/D Converters (PDF) High Output Line Driver for Single Ended Power Supply (PDF) High Quality Audio Mixer High Quality Sound Mixer Home theater system Improved PL tone decoder ISD4002-120 audio recording circuit JFET Bass Preamp Line level signal to microphone input adapter Linkwitz Cosine Burst Generator LM358 preamp Load Sensing Automatic Switch Loudspeaker Protection and Muting Loudspeaker Protection and Muting Low frequency / audio frequency dB output meter Low Noise Balanced Microphone Preamp Low Noise Microphone Preamplifier Magnetic cartridge amplifier Microcontroller (AT89C2051) based tachometer (PDF) Microphone Mixer Microphone mixer Microphone phantom power supply Minimalist Discrete Hi-Fi Preamp Minimum Theremin Kit Schematic Mono To Stereo Synthesizer / Simulator MS Stereo Decoder Musical Electronic Bell NE555 drives a speakes: Pulse Width Modulation Amplifier Noise-Canceling Headphones circuit diagram based on NE5322 opamps Novel buzzer using a relay and transformer Op Amp Limiter including SPICE simulation Panner Waveform Generator Parabolic microphone project circuit (can be used with shotgun directional microphone also) Paradoxical Sound Syntheizer Parametric And Sub-Woofer Equaliser Parametric And Sub-Woofer Equaliser Peak reading audio level meter using CA3140 opamp Peak-reading meters Phase shifter Phono Preamps For All Police Siren Power Amplifier Clipping Indicator Power Amplifier Clipping Indicator Circuit Diagram Precision Audio Millivoltmeter RC Audio Oscillator RDS Encoder Regulatable audio amplifier using a 741opamp RIAA Equalized Stereo Phono Preamp Room noise detector Room Noise Detector SCMS killer circuit for DAT decks using Sony CXD2601 signal processor chip Signal Detecting Auto Power-On Unit Simple electronic buzzer Simple light to sound converter with Youtube video Simple Surround Sound Decoder Simple surround sound decoder circuit schematic Simple two line output combiner Simplest Ever Amplifier Bridging Six-channel Mixer and Amplifier Slew rate control circuit diagrams Sound activated relay, V1 Sound activated relay, V2 Sound alarm based on LM741 opamp and LM386 amplifier Sound detector Sound Level Meter Sound level meter Sound operated switch Sound Pressure Level Meter Speaker cabinet simulator - professional-quality frequency response in a DIY-friendly circuit Speaker Microphone Circuit Speaker signals to line level inputs Speech recorded using ISD2560 Spring reverb unit Stereo Audio Isolator Stereo Audio Isolator Stereo audio line driver for running audio over long distance cables Stereo Width Controllers Subwoofer Equaliser Subwoofer Filter, Gainer, Auto Power System Super mixer with microphone input / amplifier including a PCB layout Three channel audio spectrum analyzer Three channel audio spectrum analyzer Three-Level Audio Power Indicator Tone control circuit diagram Tone control circuit schematic Tone Control using TDA1524A Tone Control IC Tone detector circuit diagram Tone display system Tone generator circuit diagram Two Tone Audio Oscillator Underwater microphone used in a home aquarium to monitor fish sounds Use amplifier phono input as line level input Using a speaker as a microphone - impedance matching circuit Variable Amplifier Impedance Various tube crossover circuits Very loud beeper (PDF) Voice / Audio Record / Playback Circuit Voice Message Recorder / Player (uses an obsolete voice recorder chip) Voice Scrambler Voice-Over Circuit Voltage controlled amplifier Voltage controlled audio panner Voltage Controlled Panner Voltage Controlled Panner Voltage Controlled Panner VU And PPM Audio Metering VU And PPM Audio Metering VU Meter Amplifier Warbler siren circuit diagram Weird Sound Generator Miscellaneous schematics 1.9 Kilojoule Coil Gun 10 GHz CW Radar based on a X-band Gunnplexer 12 Volt Toilet Tank Refiller 1uS light pulse descriminator plus F to V converter (PDF) 1uS light pulse receiver plus post amp (MISC) 2D3 Nixie clock schematic using Atmel microcontroller 6 Pole ElectroMagnet Motor (aka Simple Brushless motor) 741 Light Sensor A small collection of quick to build electronic circuit designs A spark throwing tesla coil made entirely of garbage A Two-Way Morse Practice Set Air flow detector Air flow detector using an incandescent lamp to detect airflow Amateur weather station to APRS interface ALWXI-01 Analog opto-isolator Analog pulse counter APRS system for GPS tracking Assorted digital circuits Aurora Alarm: Automated Detection System for the Northern Lights Barry's Coilgun Mark I circuit diagrams Barry's Coilgun Mark II circuit diagrans Barry's Coilgun Mark III circuit diagrans Barry's Coilgun Mark IV circuit diagrans Barry's magnetic levitation project Basement doorbell beeper (PDF) Basic Homebuilt Discrete DTL gate circuits (Diode Transistor Logic) Basic opamp circuits Bat detector Beat Balance Metal Detector Biasing Op-Amps into Class A Big Ear Stereo Parabolic Microphone Black Light Bleeper box for time reference Broadband 2MHz optical fiber receiver (PDF) Broadband 5MHz optical fiber receiver (PDF) Build logic gates using discrete parts Build your own UFO Bino-Scope unit - upgrade binoculars to become a photosensitive bino-scope Build Your Own Video-Rate 2-photon Microscope Building a Hardware Random Bit Generator Capacitance to Voltage conversion Capacitive Sensor Cat or Dog Detector - can be used to control entry on a Cat or Dog Door Chaos generator Circuit diagram for Coilgun Pistol Pskov 1100 Circuit diagrams for making logic gates from discrete components Circuit for driving a liquid crystal (LCD) shutter to simply pass or block light Circuit for gold wafer card Circuit for temperature stabilization of a MTP3055E MOSFET CMOS based electric fence design CMOS Logic Experiments Coil Coupled Operation Metal Detector Color sensor circuit Computerize Your Room/Home Count Accumulator for Radiation Levels (CARL) CW Tone Keyer Dekatron circuit diagram - device used for dividing by 10 during the valve era Delayed shutter control for Kodak DC-20 Digg Button Kit Digital Call Sign Annunciator Digital Radar Speedometer Digital Remote Thermometer Dinsmore 1490 digital compass DIY 3-axis CNC milling device DIY Plasma Globe using an automotive ignition coil DIY Pulse Induction Metal Detector with circuit diagram, PCB layout and detection coil details DIY Tesla coil - DC Powered with Plasma Output Doorbell for the Deaf Driving N-channel FETs from TTL Easy Morse Code Keyer Circuit Electric cockroach zapper Electric field disturbance monitor Electromagnetic field detector Electromagnetic Field Probe with Meter Output using an LF351 opamp Electronic canary doorbell Electronic dazer Electronic inclinometer ("clino"), a surveying device Fantastic Atom Expander FCTS Project FET based metal detector using MPF102 / J310 BF998 FETs Fish caller circuit Fluid level detector FM Morse Code Keyer Fogger smoke machine controller Full-duplex doorphone with 3 wires connection G Strain energy absorber Garmin Foretrex 101,201, Forerunner 101,201 to Serial DB9 cable schematic pinout Garmin GPS data interconnect Geiger counter Geomagnetic field detector GoldPic 3 Pulse Induction Metal Detector (has electronic kit available) GPS receiver support kit Hacking the Hot Wheels Radar Gun - includes circuit of analog front end Heathkit Groundtrack GR-1290 VLF metal detector circuit diagram and detector coil construction notes High Quality Intercom High Speed ISO9141 Interface using Motorola MC33290D ISO driver IC High voltage stun gun High voltage zappers High-speed 75MHz light receiver (PDF) Home-Built Magnetic Levitator Homemade GPS jammer using a MC145151 frequency synthesizer How to Make a Roomba Serial Interface Hydrogen Generator, PWM Circuit Induced voltage sensor delta-peak trigger for coilgun Induction receiver for tracing wiring behind walls, hearing lightning and other electric discharges Inexpensive APRS Weather Station Inexpensive seismometer project Insect Repellant Insect Repellant (22KHz audio oscillator) Intercom schematic Interesesting circuits using diodes ideal for education or introductory courses on electronics Ion detector Jacob's Ladder Jacob's Ladder Kenwood TH-D7 NMEA GPS bug fix Laboratory Control System for Cold Atom Experiments Lazer Tag Equipment Modifications Lie detector Light Activated Detector Circuit (LM393/LM555) Lightning Detector Lightning detector circuit diagram LNS Technologies Levitator Kit circuit diagram Lost keys finder using HCF4069 Low Voltage Alarm Low-power optical interrupter (PDF) Magnetic Gun. Magnetic levitation device Magnetic levitation project from Electronics Now, February 1996 Magnetic levitation project from Popular Electronics, May 1966 Magnetic levitation project from Popular Electronics, May 1989 Mains Remote-Alert - Remotely operates beeper and/or a LED via mains supply line Marshmallow Bazooka with a PIC12F615 based capacitor discharge ignition system Metal Detector using a 2 Pulse Induction Coil (PDF) Mini efficient magnetic coil launcher from disposable camera flash Miniature magnetic gun (rail gun) Miscellaneous 741 opamp schematics Miscellaneous Circuits for Idea Purposes Miscellaneous simple circuits Mobile APRS / GPS tracking system Modifications for CDV700 Geiger Counter Modulated light receiver circuit (PDF) Monitor output from Motorola Oncore GPS engine in HP Z3801A in GPS Disciplined Oscillator Morse Code Beacon Keyer Morse code display Morse Code Practice Keyer 1 Morse Code Practice Keyer 2 Navigator 555A radio direction finder (RDF) circuit diagram Negative Ion Detector Negative Ion Generator Nocturnal Animals Whisker Nokia 3310 Lcd Thermometer using DS18B20 omentary High Voltage Arc Circuit - can be used to Ignite a barbeque or a Gas in a Potato Gun Op Amp Comparator with Hysteresis with SPICE simulation Op Amp Precision Half-wave Rectifier including SPICE simulation Op-amp circuits for detectors, filtering, and power applications including photodiodes (PDF) Open loop pulse trigger module for coilgun Optical speed trap to measure the the velocity of the projectile Optical trigger module for coilgun PASCO scientific model SF-9211 stroboscope schematic (PDF) Photo sensor application note showing photodiode and phototransistor circuits Photodiode primer and interface circuit diagrams including photovoltaic and photoconductive modes Plant Watering Watcher (moisture meter) Popular Electronics Ultrasound Detector Power MOSFET module for coilgun Powerful stun gun / taser circuit diagram Project for experimenting with magnetic levitation Pulse Induction Metal Detector part 1 (PDF) Pulse Induction Metal Detector part 2 (PDF) Pulse width modulators (PWM) Pulse width to voltage converter Pulsed Induction Metal Detector circuit diagram and PCB layout Rain Detector Random noise generator Scaling ADXL50 accelerometer output Seismic detector interfaces to datalogger Select of interesting electronic circuits that require only a single transistor ideal for education Selection of run circuits to experiment with the 4017 CMOS decade counter chip SIM card reader circuit diagram Simple BFO metal detector using 2N3906 and 2N3904 transistors Simple DIY BFO metal detector Simple DTMF Repeater Controller using PIC16F84 Simple electronic keyer Simple Frequency Reader for conversion VFOs Simple Lie Detector Simple metal detector based on a PIC12F683 microcontroller Simple moisture indicator Simple nitrogen spark generator (PDF) Single chip metal detecor with a range of a few inches based on CS209A Single-Supply AC Inverting Op Amp amplifier with SPICE simulation Small selection of useful circuits Solid state tesla coil Solid State Tesla Coil and Wireless Power Sony RS-422 ADAT sync cable pinout Sound finding cricket Sound finding cricket with phase detector Static Electricity / Negative Ion Detector Stroboscope Stun gun / taser circuit diagrams Suddent ionospheric disturbance (SID) receiver Switch debouncer circuits including transistor, CMOS logic and a 555 timer based design Tesla coil Tesla coil Tesla power receiver Texas Instruments collection of buffer op-amp circuits for ADC Texas Instruments collection of differential op-amp circuits (PDF) Three component bat detector based on a PIC12F683 microcontroller Three stage induced voltage triggered coilgun Thyristor fired coilgun circuit diagram Time to dust indicator - battery powered dust indicator (PDF) Touch activated switch using CD4011 CMOS NAND gate Touch sensistive touchpad based on a PIC16F627A micro Touch switch using transistors Touch switches Two-component metal detector using a 4093 Two-tone doorbell using 555 timer u-Blox GPS receiver board Ultra Low Power LCD Indicator Ultrasonic dog whistle Ultrasonic Pest Repeller UltraSonic Radar Ultrasonic sonar unit using MAX232 to drive ultrasonic transducer Ultrasonic sound detector / sniffer Ultrasonic switch Ultrasonic transducer oscillator circuit Ultrasound detector Vareity of circuits for interfacing to/from TTL logic Variety of applications using a CMOS 4001 2-input NOR gate including a PCB layout Very basic circuits Visible and Infrared Light Detectors Voice activated switch (VOX) circuit diagram Voltage Comparator Information And Circuits Waveform conversion Weather station with pressure reading, relative humidity, indoor & remote temperature reading White's Surfmaster PI (pulse induction) metal detector schematic diagram Models, remote control toys, robotics 0-10V control for RC servos 27Mhz toy car receiver 27Mhz toy car transmitter 5 Second Ramp Generator for Locomotive Sound Card Demonstration 5 Times Around Circuit 556 Timer Stall-Motor Switch Machine Drivers A dual alternating flashing light circuit A dual tandem flashing light circuit powered by a 9 volt battery A Receive Signal Decoder A selection of robotics projects Acceleration Sensing - gesture controllers for robotic musical instruments Across The Track Infrared Detectors Adding External Meters to DC Throttles Analog controller for TekBot robot Angelfire rocket GPS payload Audible Train Approach Warning Circuit Automatic - Railway Grade Crossing Circuit (2008 design) Automatic Railway Grade Crossing Flashers Automatic Reversing Circuit for Model Trains autopilot: Do it yourself UAV AVR Line Following Robot Balancing robot (PDF) Basic DC controller for model trains (PDF) Beam robot / insect based on a PIC16F818 microcontroller Bi-Ped Project 2 Bi-Ped robot project Block Occupancy Detector For DCC Build A Roomba Bluetooth Adapter Building an RF Remote Control System Charger board for TekBot robot Circuit diagram for connecting the SRF08/10/235 sonar modules to the BS2p Basic Stamp Circuit for three axis robot arm based on stepper motors out of 5 1/4" drives Collection of BEAM robot circuits Connecting Multiple SRF08 Sonar Modules to a BS2 (Basic Stamp 2) DCC - Zero Stretching Simulator (LM555) DCC Ammeter for Model Railways DCC Circuit Breakers DCC To DC - Accessory Power Supplies Deriving power from Lego NXT motor port A Discharger for Receiver Battery Packs Distance Sensing - devices for wireless distance and position determination Doppler radar based gesture measurement system capable of delivering positional information Downed model locator Downed model locator Mark 2 Electronic millipede robot External power supply for Lego NXT FailureBot 5 - A Line Following Robot Fast Electronic Circuit Breaker for Model Railways First Across The Line Race Scorer Circuits Glowplug driver for radio control models GP2D12 distance sensor Grade Crossing Bell Ringer (LM555) Grouped DCC Block Occupancy Detectors Hexbot robot based on a PIC including source code and circuit diagram Incline Railway Control Circuit Java Bot - Simple line follower robot Launch controller for multiple rockets LED Out Circuit For Tortoise Switch Machines Lego compatible, compact rotation sensor Locomotive signal braking module Making a FRED photopopper Miniature bipedal robot that starts to walk when you clap your hands Miniature line follower robot Model Railroad - Infrared Proximity Switch Model Railroad Odometer Car Model rocket launch controller Model rocket launch controller Model Train Diesel & Horn Sound Module Moderately complex train detector using an infrared LED and an infrared detector Motor controller board for TekBot robot Motor walker circuit Multi Rocket Launcher Pad launch controller for model rockets PC Controlled RC Car PIC-Bot II using Microchip PIC16LF84 Precision Receiver Battery Low Voltage Alarm R/C digital camera controller R/C Emergency locator alarm R/C helicopter camera Rail Crossing Diamond Protection Circuit RC Receiver Battery Low Voltage Alarm RC Receiver for airplane (35MHz) RC Servo Controller with preset RF Modem Robotics Project Robotic microcontroller board Roomba robotic vaccum cleaner serial interface School Bus Signals Circuit Signal braking module Simple flashing light circuit Simple flashing light circuit Simple flashing light circuit Simple Traffic Light Controller Simple train detector using ambient light and a photocell Simplest R/C circuit Simulate the Gyralite (dual flashing headlights). Single Traffic Light Driver Circuit Slot car TV cronograph displays the lap times of your model cars on a regular TV Snuf simple autonomous mobile robot Sonar and PIR Sensor Board for TekBot / general robotics Tactile whisker for TekBot robot The Coat Hanger Walker - Simple BEAM robot Three Terminal Regulator Type Throttle (LM350K) Timed DC Throttle Timed Uncoupling Ramp Driver (LM555) Toy car hack to turn it into a synthetic rodent Traffic light controller with 20-output sequencing Train Mounted Camera Battery Charger Trooper - miniaturized Scout Walker 2 robot Turnout Anti-Derail Protection Circuits Two tone train horn Various radio control schematics Various Transistor Throttles Cicuit Schematics Walking robot Walking robot (PDF) Wire guidance sensor Motor and general control schematics 12 Volt Differential Temperature Controller 35KHz Magnetic-Radiation Remote-Control 4 Digit Keypad Switch 4-bit receiver for DC motor control 555 Based Simple Servo Controller 556 Timer Stall-Motor Switch Machine Drivers 5A H-bridge motor driver based on TIP122 / TIP127 power transistors 6090 digital decoder schematics 9V Xenon photoflash controller (PDF) A Simple Repeater Fan Controller (PDF) AC Motor Speed Controller AC switching with TRIAC from TTL Arduindo based Appliance Remote Control Assorted relay control circuits Audio Signal Detecting Auto Power-On Unit Bipolar stepper motor driver based on 74194 chip Bridge head Brushless DC electric motor control by CPLD Charge coupled bi-directional power MOSFET relay (PDF) Circuit for soft start module for induction motor Clap activated remote control CMOS control voltage for firing Crydom Soft-Start Motor Module CO2 controller for planted tanks Constant Temperature Circuit Constant Temperature Circuit Control 120VAC relay with TTL Current loop interface Dark activated switch DAS1 - 12 Volt 10 Amp Dark Activated Switch DC Motor Control Circuit DC Motor Controller using 74 series chips DC Motor Driver with L6203 DC Motor Reversing Circuit DC Motor-Driver H-Bridge Circuit DC Push Button Motor Control Circuit Delayed Power Circuit using an SCR Digital logic controller DIY Power Pulse Controller Dremel drill speed controller Driving a relay with a CPU DS1821 programmable thermostat Dual fan controller using ATTiny45 microcontroller Dual stepper motor drivers using UDN2540 Dual Stepping motor drivers using UDN2540 Electric heater thermostat Electronic circuit diagram of cell phone SMS remote control device Electronic Control for DC Motors Using Discrete Bridge Circuits (PDF) Fan control based on a TL082 opamp and IRF510 power MOSFET FAN Thermostat controlled by IR remote controller Finger touch activated switch (PDF) GSM SMS javljalnik ALSMS-01 (page in slovenian )SMS remote control project H Bridge controller for DC motors H Bridge Motor Control Circuits H-Bridge Circuit H-Bridge Motor Driver Using Bipolar Transistors Heating System Thermostat High And Low Voltage Cut Off With Time Delay High and Low Voltage Cutout with delay and Music High current PWM controller based around a 555 timer HIGH or LOW Power Switch For Lights or Small Motors Home Automation Over Internet Homemade Water Drain Pump controller Hot Water Tank Level Indicator How to Make a PWM Circuit without a Microcontroller LDR light/dark activated relay switch Light / dark activated relay Light detector Light Operated Switch Light switch using LDR Light/dark detector Light/Dark Detector drives a relay Line-powered Xenon flash transmitter (PDF) Machine vibration triggers hour meter (PDF) Mains Power Load Sensing Automatic Switch Micro-step driver - connect a bipolar steppe motor to a PC through the parallel port Microstepping with PBM3960 and TEA3718 Modular relay system MOSFET H-BRIDGE schematic and theory Motor speed controllers MotorDriver V1.0 - Dual DC Motor Driver Board (LMD18200T based, 55V 3A, 6A peak) - PDF No-Hum Fan Controller NPN transistor circuit for relay control (relay driver) One component stepper motor driver Op Amp based PID Controller circuit with SPICE simulation Optically isolated stepper motor controller Optically isolated TRIAC driver Over / Under Voltage Cut-Out PA fan temperature controlled speed motor speed controller Pulse width modudulator using 555 timer IC Pulse Width Modulation DC Motor Control Pulse Width Modulation DC Motor Controller Push Button Motor Control Circuits Pushbutton one-shot and latch (PDF) PWM DC motor control with SG3525 PWM DC motor driver and control with SG3525 PWM DC Motor Speed Control PWM Heater fan controller based on PIC12F675 PWM motor controller PWM Motor Speed Controller / DC Light Dimmer PWM Motor Speed Controller / DC Light Dimmer PWM Motor/Light Controller circuit diagrams Radio Remote Control using DTMF Relatively simple thermostat circuit diagram Relay circuit for relay control via an RS232 port Relay circuit using 74LS573 to driver 5V DC relays Relay controller based on Microchip PIC16F84 (PDF) Remote Motor Controller Rolling code 4-channel UHF remote control Safe Universal Mains Switching Box Selection of PWM driver circuits for electric DC motors Serial servo controller Several stepper motorol control circuits Shadow activated (or hand wave) motion detector Simple 120 VAC motor speed controller based on a TRIAC Simple keypad operated switch Simple Servo Controller using 555 Timer Simple temperature regulated FAN speed controller Simple Two Speed Contactor DC Motor Controller Smart switch, short press for on, longer press to turn off Solenoid starter Solid state relay (PDF) Solid-state power controller Sound operated switch Stepper motor controller Stepper motor controller Stepper Motor Controller using 4027 flip-flop and 4070 XOR gate Stepper Motor Driver using L298 and L297 Stepper motor driver using PIC12F675 Stepper motor driver using PIC12F675 that offers serial port command interface Stepper Motor Driver using TEA3718/3717 Stepper motor positioner Switching solenoid driver Temperature monitor using 741 opamp Thermal cooling fan controller Thermo-Fan to keep your amplifier or other equipment cool Three electronic circuit diagrams for thermal controllers including linear and PWM control Time Delay Relay Time Delay Relay II Touch switch Touch switch based on CD4011 flip-flop Touch Switch using 4011 CMOS NAND Gate IC Touch Switches Unipolar stepper motor driver based on 74194 chip Variety of simple motor control circuit diagrams using SCR or TRIAC Various CNC mill circuit diagrams and other DIY CNC mill information Voice activated switch using MC2830 Voltage comparator switch Water Detector With Sump/Bilge Pump Controller Water system controller (PDF) Wireless RF PWM dual motor controller Music related schematics (also see Audio) 100W Guitar Amplifier Mk II 2 Note Ribbon Controller 25-pin PC serial port to MIDI synthesizer interface cable 3 Channel Color Organ 8 Note Tune Player 8 note tune player 9-pin PC serial port to MIDI synthesizer interface cable A refined Fuzz Face. Schematic and PCB layout. Amiga MIDI interface Ampeg SB-12 Portaflex adapted for use as a bass overdrive stompbox An ultra-flexible tonestack with clean boost. Schematic, photo, and PCB/perfboard layouts. Apple Mac to MIDI synthesizer interface cable Apple Macintosh MIDI interface schematic (basic version) Apple Macintosh MIDI interface schematic (deluxe version) Arduino MIDI interface (Arduino MIDI Drum Kit and Spooky Sound Trigger) B. Blender: Blends an effects chain with the input signal. Works well with bass guitar Bassline synthesizer/sequencer Big Muff Pi variant using Bazz Fuss as clipping stage. Schematic and and PCB/perfboard layouts. Boogie MkI adapted for use as a distortion stompbox Build A Stereo Synthesizer CD4049 based distortion. Schematic, PCB/perfboard layout, and photos. Closer look at the FET booster based on a vintage Fender 12AX7 input stage. Colour (Sound) Organ Colour (Sound) Organ Colour Organ based on a PIC16F84 microcontroller including schematics and source code Compact DJ station Daisy MP3 player project Digital Delay Unit For Surround Sound Digital Guitar Tuner Distortion effects using an LM386 audio amplifier IC DIY Serial MIDI Interface (80C51/80C31 Version) Drawdio - A very simple musical synthesizer that uses the conductive properties of pencil graphite Drum percussion sensor schematics Drum Tone Oscillators Dual parallel buffered effect loops with blend control. Schematic and perfboard/PCB layouts Electronic metronome Faux-phaser circuit with LFO and manual (wah pedal) modes. Schematic and and PCB layout. Fender Princeton adapted for use as a distortion stompbox FET overdrive developed as a Tube Screamer alternative. Schematic and perfboard layout. Guitar Fuzz Effect Guitar fuzz effect Guitar Reverb Effect Version 2 Guitar Reverb Pedal Guitar Reverb Pedal Guitar Tremolo Unit Guitar Vibrato Unit Guitar Vibrato Unit Circuit Diagram Homebuilt MP3 Player Improved Silicon Fuzz Face. Schematic, build notes, photo, and PCB/perfboard layouts. Infinite melody for music synthesizers JT-11P-1 in 4-Way Active "Guitar Splitter" (PDF) Liquidator Tube Phaser/Chorus Effect Lossless portable digital audio player using the Microchip PIC32 Marshall 100W Super Lead adapted for use as a distortion stompbox. Schematic and PCB layout. Marshall 18W adapted for use as a distortion stompbox Matchless DC/30 adapted for use as a distortion stompbox Metronome Circuit Microcontroller MIDI interface MIDI Controller Footpedal MIDI Drum Machine Analog Input Schematic MIDI drum machine project MIDI interface / cable tester MIDI keyboard circuit diagram MIDI merger schematic MIDI Pedalboard Encoder midi2cv8 to Drum Tone Board Connections Midibox 64 Miniature metronome MP3 Player circuit schematic Mr Smooth is a clean boost to mild overdrive effect Mr. EQ - a simple, yet potent DIY equalizer Music player built on microcontroller AT91SAM7S256 with ARM core Musical Instrument (Expandable) Graphic Equaliser New clipper circuit diagram (based on TL071 opamp) Octave screamer Peppermill overdrive - A simple, transparent overdrive. Schematic and PCB/perfboard layouts. Percussion generator circuits Portable Mixer with high-quality modular design (9V battery powered) Portable MP3 music player Practical MS Decoder Circuit Real-world MIDI interface platform project including circuit diagram and PCB design files Schematic of a Rockman-like distortion. Schematic and PCB/perfboard layouts. Selection of solid state and tube guitar amplifier and effects circuits Serial MIDI interface Simple Colour Organ Simple colour organ Simple line mixer Simple metronome using LM1458 Simple MIDI switcher Simple MIDI tester Simple open source MP3 player with SD/MMC memory card support Simple Transistor Organ Sound Effects Generator Sound Effects Generator 2 Sound Lab Mini-Synth analog music synthesizer Spring reverb Spring reverb unit Spring Reverb Unit For Guitar Spring Reverb Unit For Guitar or Keyboards Stage center reverb unit circuit schematic Standard MIDI to MIDI interface cable diagram Stereo Width Controllers Supro 16T adapted for use as a distortion stompbox The 203 Theremin - A Battery-Operated Version of the Wien-Bridge Theremin Theremax Theramic Circuit Schematic Theremin Theremin controller Tone Filters for Electronic Organs (PDF) Transistor organ Treble Booster/Overdrive including a perf board circuit layout Tube Screamer-based overdrive. Schematic and PCB/perfboard layouts. Two channel distortion circuit Ultra Simple Bass Guitar Compressor Umble - A distortion stompbox, inspired by Dumble amplifiers. Schematic and PCB/perfboard layouts. Using the Hot Springs Reverb reverberation unit Versatile FET booster engine. Schematic and perfboard/PCB layouts. Vocal zapper Vox AC-30 Top Boost adapted for use as a distortion stompbox Wave Multiplier for music synthesizers Zonk Machine and Treble Booster PC related schematics 160 Baud ALDL Hardware Interface 300/1200 baud BAYCOM MODEM (revision and improved) 3-axis stepper motor controller for PC parallel port 7 segment rolling display using PC 8-way relay interface board for PC parallel printer port 9-pin null modem cable A Serial Infrared Remote Controller ADMS programming Cable for the Yaesu FT50, VX1 and VX5 Analog Signal Acquisition for PC Printer Port Apple II/II+/IIe IDE Drive Interface Assorted computer interface circuits Basic Stamp I & PC Relay Controller Bell 202 and CCITT V23 Compatible FSK Modem Circuit Build your own iRDA SIR Transceiver (Dongle) using MCP2120 Build your own MARES dive computer IRIS interface for RS232 Building an Infrared Transmitter for Your PC CCD linear image sensor to PC parallel interface Circuit for interfacing a relay / solenoid to a PC based on a 2N7000 FET Circuits to computerize your room/house CNC controller that interfaces directly to a PC parallel port without using a microcontroller Commodore 64 24-bit parallel port interface with 8255 Computer Controlled Frequency Counter/Logic Probe Computer microphone Connect other circuits to PC joystick port Connect two CD-ROM drives to one soundcard Convert Atari-style joystick to PC joystick port Dallas DS1620 based USB Digital Thermometer DB-9 Connector to DB-25 (both RS-232) DCF77 receiver to PC RS232 serial port interface Ericsson phone to PC serial port interface Ethernet interface for Commodore 64 computer Extremely simple ADC for the PC (parallel port interface) Fake Joystick circuit Fax to modem interface FM radio for a PIC (uses TDA7000 IC which is now obsolete) FM radio with PC parallel port interface Game boy camera PC serial interface General purpose ISA interface card for PC Get power out of PC parallel port Get power out of PC RS-232 port Getting power from RS-232 interface GPS receiver (Gamin, Eagle etc) to PC interface cables HAMCOM & SoundCard MODEM using serial- or soundcard audio HAMCOM (SSTV, RTTY, FAX...) modem using PC-speaker for TX HAMCOM (SSTV, RTTY, FAX...) modem using serial audio for TX Headphone driving circuit for soundcards Hi-Fi PC Speaker System Homebuilt RS232 LCD Interface Homemade Serial to Nokia MBus Interface on a PCB, without using Zener diodes How to construct Garmin GPS receiver interface cables How to get power from PC to your circuits i2c-tiny-usb, a simple i2c interface for the usb port iLINK Interface Interfacing 16x2 character :LCD to parallel port Interfacing PC sound card to SSB rig iRDA interface for motherboard using Vishay TFDS4500 Isolated Full Duplex RS232C Interface Isolated Full Duplex RS232C Interface for a PC Isolated RS422 adapter for PC serial port Jasmin floppy disk controller schematics Laptop Computer Serial Port Power Booster LCD2LPT with LIRC (LCD to LPT printer port) interface LCD2USB, cheap open source text LCD interface Linux Infra-red Remote Control (LIRC) Mac Serial Port (RS-422 DIN-8) to RS-232 DB-25 Mac to HP48 cable pinout Machine Independent Parallel Interface Magnetic card reader to PC RS-232 port interface based on a PIC12F675 micro MIDI cable for Sound Blaster cards More accurate PC/AT clock MS-DOS EEPROM Programmer New and Improved Sound Card Packet Interface tested with PSK31 and APRS Null Printer Adapter Parallel (Printer) Port Interface PC based digital thermometer based around a Dallas Semiconductor DS1621 PC based Frequency Meter PC based thermometer based on Dallas DS1621 PC electrically isolated RS422 interface using SN75176B or MAX485 PC electrically isolated RS485 interface using MAX487 or SN75176B PC interface for point controller PC ISA board containing a Z80 microprocessor (coprocessor card) PC ISA Card Random Number Generator PC parallel port eight DC power switch cam driver two unipolar stepper motors, lights etc PC Power Reboot Circuit for ATX power supplies PC serial port parastic mode interface for 1-wire DS18S20 and similar 1-wire temperature sensors PC speaker volume control circuit PC thermometer using PC game (joystick) port PC-based ISA data acquisition and control board PG31 GPS RS232 GPS development board PG31 GPS RS232 USB development board PG4S programming Cable for the Kenwood TM-V7 and TM-G707 Pic-Plot GPIB to RS-232 converter Pic-Plot2 GPIB to USB converter PS/2 Keyboard Or Mouse based on an Arduino PTT and soundcard interface for the TM255/455 PTT and/or soundcard interface Radio clock for PC's Radio Interface Box for the Motorola Radius GP300 Relay interface add-on board for PC RFID evaluation kit for PC serial port (PDF) RS232 - Lowe HF-225 interface RS232 DB-9 switch to flip between two serial ports RS-232 line monitor and loopback cables RS-232 Protocol Analyser RS232 RS485 USB Converter Board RS232 serial to USB converter cable circuit schematic RS-232 surge protection RS232 to RS485 converter schematic to connect PC to RS485 network RS-232 to TTL cable RS-232 to TTL level translator RS232C Level Converter Sanyo 20EZ monitor circuit diagram SB-Bus Drivers Introduction and Circuit Diagrams Schematic of a standard PC joystick Sega 3D glasses interface circuit diagrams Serial port temperature datalogger Serial servo controller for interfacing hobby servos via RS232 to a PC Serial to parallel converter - connect a large number of digital outputs to a PC parallel port Short circuit protected power supply from PC 12V supply Simple and easy build RS232C-RS485 converter Simple Hankel USB oscilloscope for a PC Simple music synthesizer for an ATARI Simple Parallel (Printer) Port Interface Simple PC SmartCard reader Simple PC thermometer for serial port but using R/C network for measurement Simple RS232 Level Converter based on a MAX232 including Eagle PCB and schematic files Simple RS-232 serial port buffer circuit Simple RS232C Level Converter using Transistors Simple stepper motor driver for PC parallel port Small circuit and PCB layout for recording to PC Sound Monitor / Pre-amp SmartCard PC Emulator Sound Blaster Microphone Preamplifier SPDIF RCA to (Optical + RCA) Adapter Stepper motor controller for PC parallel port SWTP PR-40 Printer Interface Schematics The Great Z80 Computer Project The KD2BD Pacsat Modem Thermal fan control circuit designed for overclocked PCs TiltStick, a motion sensing device (USB interface to accelerometer) TM-441 9600bps packet modification Transceiver to PC interface with a hardware DTMF detector and galvanic isolation (PDF) Transceiver to PC soundblaster interface for digital operating modes (PSK-31, RTTY, SSTV etc) USB camera circuit USB LCD/VFD Controller Hardware USB to parallel port converter using Cypress CY7C68013A-56PVXC Using a PC power supply as a benchtop power supply Using the joystick port as general purpose input Various sound card interfacing circuit diagrams Virtual USB Keyboard based on an Arduino Yaesu FT-897 - PC interface (PDF) Yaesu VX-7 / VX-7R to PC interface Z80 Computer PDA / music player interfaces and schematics 1.5V iPod Microphone (PDF) Aladin interface Apple iPod and iPhone dock pinout Casio calculator interface schematic Casio datalogger Design and build your own iPod docking station DIY iPhone 3G Charger circuit DIY iPhone Charger circuit DIY Microphone Cable for iPod Touch (2nd Gen) Fitting a JTAG interface to an iPAQ 3600 Gameboy MIDI interface circuit schematic and notes on Linux development for Gameboy Interfacing ADXL202 accelerometer to PalmPilot iPod / USB MP3 charger using MC34063 switchmode regulator Mass storage and printer interface for the FX-700P calculator Palm Keyboard interface board Palm PDA based datalogger Palm Pilot, Palm III, V, VII, VIIx, Handera interface port pinout PalmPilot turbo boost guage interface Portable iPod charger Serial interface adapter for iPod Linux SHARP palm-top/hand-held to RS232 serial converter SHARP palm-top/hand-held to RS232 serial converter TomTom One V3 connector pinout USB charger for iPod using 7805 linear regulator Wireless local network for PalmPilot (large PDF) Photography related electronic circuits A DIY Arduino Intervalometer (shot timer) for your Canon SLR with circuit and source code A home-made light-operated camera trigger using the stamp microprocessor A simple home-made light-operated camera trigger AI-1 ("All-in-one") Remote - photographic accessory that you can build Arduino based laser trigger for a DSLR camera using an LDR to detect when the beam is broken Arduino based motion triggered camera using a PIR sensor Arduino based photography intervalometer including circuit schematic and source code Arduino based Time-Lapse Camera Controller Beam-break Detector For Camera Shutter or Flash Control Building a Digital Intervalometer - includes circuit diagram and suggested layout Camera Axe open hardware and open software project for camera triggering Camera remote control system using Basic Stamp CamTrig - A home-made light-operated camera trigger Canon DSLR cable shutter release usin 4N25 for optical isolation Computer controlled EOS camera shutter trigger Computer Sound Port Shutter Tester Computerized Shutter Control of Canon DSLRs Control your camera (Canon DSLR) with your Palm PDA Controlling your SLR Camera from an Ipod Darkroom camera shutter timer Densitometer & Intervalometer projects Densitometer & Intervalometer projects including hand-drawn block diagrams only Digital cameras (AGFA, Olympus) to PC (COM) cable pinout DIY Intervalometer for a Canon SLR camera Dual cable (serial + USB) for Nikon Coolpix cameras Electronic shutter release with ultrasonic remote control Flash Slave Trigger Flash slave trigger Flash Slave Trigger for Digital Camera High speed flash photography for amateur photographers High-speed flash photography for amateur photographers (includes several circuit diagrams) Homebrew Wired Remote for Canon EOS 350D Camera How to Build Your Own Light Meter (PDF) Infrared remote control with intervalometer function for Nikon cameras IR Remote Control for Nikon cameras, standard version Kodak DC-20 camera interface (PIC12C509) Kodak DC-20 camera interface (PIC16F84) kShutter: Simple remote shutter for Nikon Coolpix camera kShutter2: Advanced remote shutter for Nikon Coolpix cameras Large collection of strobe / photoflash circuit diagrams Lightning Activated Camera Shutter Trigger Lightning Activated Camera Shutter Trigger Lightning activated camera shutter trigger Lightning shutter trigger for a camera using an Arduino Making your own RS-60E3 Remote Control for Canon EOS cameras Nikon Coolpix 950 / 990 / 995 Flash-adapter Nikon IR-Remote Control based on Atmel ATtiny13 Nikon programmable memote / intervalometer Programmable Hi Speed Flash & Camera Trigger Programmable Optical Slave Flash Trigger for Digital Cameras using PIC12F675 Remote shutter (or 'cable release') for SLR and DSLR cameras Sea & Sea TTL (Motormarine II, SX-1000) Flash Interface (underwater photography flash) Serial cable for Casio QV-200 digital camera Simple sound syncronizer / sound activated shutter trigger for amateur photography Slave flash trigger Slave Flash Trigger Circuit Slave flash trigger with counting logic (Silicon Chip Mazine article) Stop Action 3D-Photography using an audio flash trigger Timelapse photography with the Canon 10D using a 555 timer based circuit Universal Exposure Timer and Event Counter Universal sound and optical slave flash trigger Using an Apple II+ Computer as a Flash Intervalometer (PDF) Power supplies and control schematics +9V *and* -9V from one battery 0-14 volt, 0-2 amp current limited variable power supply regulator 12 Vdc - 120 Vac Inverter Schematic 12 volt battery monitor 12 Volt Gel Cell Charger 12 volt power supply 12 Volt Switching Power Supply circuit diagram and PCB layout 12V 30A power supply 12V Lead-Acid Battery Monitor using LM3914 12V to 120V Inverter 12V, 4-AA Cell Differential Temperature Charger 13.8V 30-40A Power Supply (PDF) 1A Variable Regulated Power Supply 200 Watt Modified PC Power Supply 13.5 Volt 14 Amp 3.3V / 5V Regulated Power Supply Circuit 3rd harmonic distortion meter for measuring the quality of AC supply 5 volt power supply 500W low cost 12V to 220V inverter 6V to 12V Converter 6V to 12V Converter AC Power Meter Active Power Zener Adjustable power supply using LM317 Adjustable Voltage Regulator using a 7805 or other fixed linear voltage regulator instead on LM317 Advanced High Voltage PSU circuit Alkaline battery charger Alternative power source for Magellan GPS receivers Amplified zener regulator Assorted power source and control circuits Automatic 12V Lead Acid Battery Charger Automatic 9V NiCad battery charger Back And Forth - Bidirectional Bipolar Stepper Motor Driver Basic 78xx series regulator mains power supply circuit diagram Basic Power Supply Basic Solid State Relays Basic UPS Power Supply Battery Characterizer Battery Charger Ideas Battery Charger, Current and Voltage Regulated for Sealed Lead Acid batteries Battery Low Voltage Beeper Battery Low Voltage Beeper Battery voltage monitor Bench power supply that allows a number of varying output voltages to be preset. Includes PCB layout Breadboard supply - very low dropout adjustable power supply Build A 10 Amp 13.8 Volt Power Supply Build a breadboard power module for integrated circuits Build A High Performance Voltage Regulator From Discrete Components Build A Simple Rechargeable CMOS Battery Car Ignition Coil Driver from 110V AC Car Ignition Coil Driver from 12V DC - Can be used as an electric fence Charge Monitor for 12V lead acid battery Charger for gel lead acid batteries Cockcroft-Walton voltage multipliers (PDF) Compressor-mate power protection for refrigerators, freezers and air conditioners Controller for hybrid (photovoltaic- wind turbine and diesel engine) power plant Current booster for 78nn series voltage regulators DC to AC inverter using a 555 timer DC Voltage and Current Source Digital bench power supply based on a PIC16F870 Dual (postive and negative) 12V power supply Dual Polarity Power Supply Dual Polarity Power Supply Dual Polarity Unregulated PSU For High-End Audio Amps Dual power supply Dual regulated power supply Dynamo Current and Voltage Regulator Efficient unipolar stepper motor driver (only uses power when it makes a step) Emergency power system Expanded Scale Battery Volt Meter Expanded Scale Battery Volt Meter Fast NiMH / NiCd Battery charger Filtering PC bus POWER Fixed Voltage Power Supply Fixed Voltage Power Supply Flyback transformer driver Fuse blown indicator Fuse monitor / alarm General purpose portable DC power supply using rechargeable C cells Generating -5VDC from +5VDC Gyrator circuit High Current Power Supply High Current Power Supply High current regulated power supply High Side Current Monitors (LM358, Zetex - ZXCT-1009) High Voltage Converter: 90V From 1.5V High voltage DC generator High Voltage High Current Power Supply High Voltage High Current Power Supply High-Voltage Pulse Generator HV supply: 12VDC in, 12KV out Inverter, 12 volt unit, MOSFET design Inverter, A 12 volt unit, Very Basic type Lead acid battery charger with float Lead/acid battery charger Lead-Acid Battery Monitor LED battery voltage monitor. A fuel gage for your gel cell battery. Lithium Battery Rejuvinator Lithium Ion Battery Charger based on a PIC micro including circuit diagram and source code LM311 Thermostat circuit diagrams LM317 Regulator Circuit LM3914 battery monitor Low Battery Voltage Cutout Circuits Low Power LED Voltmeter Low Power LED Voltmeter Low Voltage Alarm for batteries and other volatile DC power sources Low-dropout 12V regulator (LM324) Machine power loss beepter (PDF) Multiple voltage power supply N.O. Magnetic Reed Switch ON /OFF Circuit (SCR equivalent) Nagative voltage generation using 555 timer Negative Supply from single positive Supply using 555 timer Negative voltage generator Nicad battery charger NiCad Discharger for Tx & Rx Packs NiCd Cell Charger Nine Volt Battery Eliminator One 9V battery gives +18, +25, +33V Op-Amp Current Source with Floating Load including SPICE simulation Power reminder beeper (PDF) Power supply metering circuits for measuring both voltage and current Power supply provides +5VDC regulated, +10VDC unregulated and 7.5VAC Preselect Twin Coil Switch Machine Circuit Pulse Charger for reviving tired Lead Acid batteries PWM DC Motor Speed Control PWM Motor Speed Controller / DC Light Dimmer PWM Motor/Light Controller PWM Motor/Light Controller PWM Motor/Light Controller variants Regulated 12V supply Regulated Power Supply Circuits Simple +5V power supply circuit Simple Capacitance Multiplier Power Supply For Class-A Amplifiers Simple constant current source Simple DC Adapter Power Supply Simple NiCad battery charger using LM317 Simple switching power supply Simple switching power supply (mains operated) Simple switching regulator (experimental) Simple voltage booster based on Linear Technologies LT1372, includes PCB design Single to 3-phase power conversion Small battery-powered USB charger including circuit diagram and PCB layout Snowmobile GPS power adapter Solid state relay circuit Solid State Tesla Coil/High Voltage Generator Student DC power supply Team digital - SCR16 - Twin Coil Switch Machine Adapter Temperature Controlled Nicad Charger Temperature Controlled NICD Charger Tesla coil / HV generator Transformer Secondary Voltage Reduction Transformerless Power Supply Transformerless Power Supply TTL power supply with crowbar protection Unplugged power cord alarm Unregulated power supply USB charger Using Pass Transistors Beef Up Voltage Regulator current output Variable Dual Lab Power Supply Variable power supply Voltage and current regulated power supply Voltage doubler Voltage Inverter Voltage Inverter Voltage inverter Voltage Inverter using 555 Timer Voltage Inverter using LM380 audio amplifier IC Voltage Monitor using UA741 operational amplifier Voltage monitor with LED indicator Radio-frequency schematics (also see Transmitters) 1 Watt 2.3 GHz RF Amplifier Using a MRF2001 1.5 W RF Power Amplifier type class-C 10 meter (28MHz) band RF amplifier 10 MHz WWV Receiver 115200 RS232 QPSK RF modem project 118MHz to 136MHz aircraft receiver circuit diagram 1300MHz - 1500MHz antenna with amplifier based on two MAR-8 RF amplifiers 136 kHz direct conversion receiver 14MHz SSB 10mW Transceiver 15M CW Transceiver Design 160m mini portable End Fed Half Wave Tuner - MkII 175KHz inductive pulse receiver (PDF) 17M to 6M transveter 18 dB LT1253 DDS Amplifier 2.3 GHz Power Amplifiers 20 Meter CW Transceiver 20 meters CW QRP Transceiver (PDF) 20 Watt GaAaFET Power on 2.3 GHz 200-400 MHz voltage controlled oscillator (PDF) 20dB VHF Amplifier 222 MHz Transverter 23 dB Bipolar DDS Amplifier 2304 and 3456 MHz Power Amplifiers 2m (144MHz) Dual Gate FET Low Noise Amplifier 2N2222 40 Meter CW/DSB Transceiver 30 Meter, Discrete Component CW Transceiver Built Manhattan-style 30 W Digital Wattmeter for RF (0-500MHz) 30 watt FM linear amplifier 300 baud RF modem circuit schematic 30M Direct Conversion Receiver Project 30M PSK31 Transceiver 4 channel 433MHz remote control transmitter / receiver based on SM5162 and SM5172 chips 40 Meter Band Direct Conversion experimental receiver 40 Meter Popcorn Superhet Receiver 40 Segment LED S-Meter 40 to 6 Meter "No Tune" Transverter 40m band direct conversion receiver 42 Mc Band to 88 Mc Band (retrofit converter) Project 450-2000KHz AM receiver (ZN414) 455 Khz MF to AF converter used for DRM reception in a Yaesu FRG-100 receiver 45-860MHz Radio receiver based on UV916-tuner 49MHz walkie-talkie 5 tubes SSB QRP Transceiver for 20m Ham band 5 watt, 80 meter QRP CW Transceiver 50 MHz Receiver based on MC3372 50 MHz to 10 MHz receive converter 50MHz converter project based on a NE602/SA602/NE612 50MHz RF Power Amplifier using BFG97 555 Time-Difference-Of-Arrival RDF 56K RF Modem 6 Meter SSB transceiver 60-120MHz FM receiver with AFC 60W Linear amplifier using IRF840 power MOSFET 60W RF linear amplifier using IRF840 6m SSB & CW QRP transceiver 73MHz remote controller hallogen light 75 Meter QRP SSB Transceiver 78-80 MHz Superfast Scanner using a DDS (direct digital sythesizer) 7MHz SSB Transceiver 80 Meter CW ARDF receiver 80 meter direct conversion receiver 80m band direct conversion receiver 80m SSB & CW QRP superhet transceiver A compact L-match ATU for portable use A Multimode Phasing Exciter for 1 to 500 MHz from ARRL (PDF) Active antenna 1 to 20dB, 1-30 MHz range Active Antenna AA-7 HF/VHF/UHF, 3-3000MHz Active Antenna Experiments Active Antenna for AM-FM-SW Active RF antennuator Advanced VHF power meter (PDF) Aircraft Radio Communications Receiver AM BCB radio receiver AM receiver circuit diagram AM receiver for aircraft communications AM Short Wave Broadcast Receiver circuit diagram AM to FM conveter AM/FM/SW active antenna AM-Receiver for Aircraft communication (118.250MHz) An end-fed antenna, L-match coupler and resistive bridge for HF An Inexpensive Tone Encoder Assorted RF circuits Audible S-Meter Aviation band receiver Basic 10GHz / 24GHz gunplexer / gunn diode control circuit (PDF) Basic RF oscillator Basic Vox Circuit Bi-Directional 2.4 GHz One Watt Amplifier Bi-Directional 900Mhz One Watt Amplifier Bipolar transistor RF mixer Bootstrapping a Phase Locked Loop for Better Performance Broadcast-Band RF Amplifier Bug detector / countersurveillance monitor Bug detector with beep using 7413 or 74LS13 Build a COS Detector to detect the presence of a carrier on a receiver Build a good GaAs FET preamp for 2 meters, 222MHz or 440MHz Car radio tunes the amateur bands Cascode 7 Experimental Receiver Cascode Hybrid-Based WWV Receiver for 5 MHz CB (27MHz citizens band) 2.5W transmitter CB (27MHz citizens band) receiver Class B series modulator Class E Power Amplifier Design (136KHz operating frequency) Compact 20 - A 14 MHz Direct Conversion Receiver Convert 2m VHF FM PMR transceiver Motorola Radius M110 into an amateur radio Converter to Hear Amateurs on your FM Radio Converter to yune six metres on your two metre receiver COR Carrier Delay timer / Hang Timer Crystal Radio Crystal radio circuits including diode performance comparison DC40 - 40M Direct Conversion receiver Deluxe Direct Conversion Reciever Demodulator Schematic/Design using Gilbert Cell Mixer Digital display and VFO stabiliser using a PIC microcontroller and LCD Digitally tuned radio board to create an embedded FM radio controlled by a Mega128 Direct Crystal radio receiver examples Dopler RDF (radio direction finder) circuit DSP-RDF Doppler Radio Direction Finder circuit schematic - complete kit available Electroluminescent Receiver Kit includes circuit diagram Electronic Eavesdropping Devices Detector Electronic Eavesdropping Devices Detector (bug detector) Experimental DSB/CW QRP rig for 20 and 40 meter bands (PDF) External antenna for the GPS-38, Magellan 2000, or Eagle Explorer GPS receivers FM radio active antenna Four channel RF remote control Four Channel Wireless Transmitter and Receiver using RF modules (PDF) FPGA Based ADS-B Receiver and Decoder Galvanic isolated CAT & audio interface for amateur radio GPS jammer HF 10 watt amplifier for 18MHz using a 2SC1969/2SC1944 transistor HF/6M Antenna Tuner Preselector and Antenna Switcher HF/VHF mini portable antenna tuner HF/VHF portable antenna tuner High quality AM through your FM stereo High-Performance Direct-Conversion Receivers from ARRL (PDF) High-Performance, Single-Signal Direct-Conversion Receivers for ARRL (PDF) Homebrew 20m CW Transceiver Homebrew 30m CW Transceiver Homebrew 40m CW Transceiver Homebrew 6m DSB Transceiver Homebrew 6m SSB/CW Transceiver How to Build a 300MHz AM, RF Remote Control System ICOM CI-V interface with RS232 RTS to PTT Improved AM-Receiver for Aircraft communication Improved FM Stereo Modulator inexpensive high speed microwave data link using an Alpha Gunnplexer for 10 Mbps data rate Junk Box NDB Low Pass Filter K8IQY's Original 2N2/40 CW Transceiver Rig Kenwood TR-7950 manual & schematics (PDF) KL 400 RF linear amplifier LF to HF Converter Linear FM 50 watt amplifier with BLY90 Linear FM 50Watt with BLY90 Low Frequency Circulator/Isolator Uses No Ferrite or Magnet (PDF) Low Power RF ID Transponder (PDF) MC13136 based narrow band receiver Medium Frequency TRF Receiver metre receiver MF and HF Receive Antenna Splitter Montreal Doppler 3 DF (direction finder) unit Morse Code Beacon Keyer Multi band SSB transceiver construction project Multiplier Generates Odd Harmonics (PDF) MW Enhanced Crystal Receiver using 741 IC MW/SW Radio receiver Novel crystal set requires no antenna, earth One transistor FM receiver One Watt 2.45 GHz Linear Amplifier using RF Micro Devices RF2126 One watt class-C RF amplifier (PDF) Op Amp Radio Op-amp based radio receiver Op-Amp Radio Passive grid (tube based) linear amplifier Phase Locking and Tuning Phase-Locking ULNs for Optimum Performance PLL synthesized FM radio that can decode DTMF Pocket sized 20m (30m) CW QRP transceiver Popcorn Direct Conversion Main Frame PSK Transceiver - Unique transceiver design does not use a SSB transmitter QRP - Circuits for measuring RF Voltage, RF Current, RF Power, SWR QRP Antenna Tuner R2T2 Haywire Home Station Radio Wave Alarm Receive Loop Preamplifier for LF reception Receiver based on NE602 Receiver building blocks Regenerative receiver for the AM broadcast band using two transistors Regenerative Short Wave Radio Regenerative shortwave receiver RF Actuated Keying Monitor RF front-end for triple conversion GPS receiver (PDF) RF Isolator Uses Differential Amplifiers RF noise bridge for HF RF Power Amplifier Module using Toshiba S-AV10H RF Power meter / dummy load RF preamp circuit diagrams RF Sniffer under 0.5MHz to above 500MHz RX3302 receiver module schematic SA602, SA612 RF Mixer SCA Adapter - listen to advertisement free background music on FM broadcast radio SCA Subcarrier Demodulator for FM broadcast stations Send Morse on your VHF Rig Sensitive LW/MW/SW Shortwave general coverage receiver Shortwave received circuit diagram Simple 40 meters CW QRP Transceiver (PDF) Simple ADS-B aircraft transponder decoder based on a PIC18F2550 microcontroller Simple CW identifier for a FM repeater (PDF) Simple Dual Band SSB Transceiver (20/40 meters) Simple home made ADS-B receiver that takes IF from a modified receiver Simple RIT circuit based on a 2N7000 FET Simple Time-Difference-Of-Arrival RDF Simple wireless radio data link Single transistor receiver for SSB, CW, AM using a VHF dual gate MOSFET Smooth Tone Clickless CW Sidetone Generator Some experiments with active or voltage probe antennas (VPA) SOP direct conversion receiver SOP receiver (PDF) SSB linear amplifier made from a bunch of 2N2218 transistors SSB Receiver / Exciter and Linear amp SSB transceiver for 80M Stacked Torroid VFO Experiments 2008 Subcarrier adapter to listen to hidden subcarrier signals on FM radio Super 80 ultra-simple SSB receiver for 3.5 MHz a basic superhet Super improved AM-Receiver for Aircraft Super Scanner 45-860MHz with 0.01Hz stepsize Superior TV-tuner receiver 45-860MHz in 2500Hz step Superregenerative 27MHz receiver SW30+ 30 Meter CW Transceiver Switching Diode Frequency Doublers (PDF) SWR bridge covering HF to VHF The MRX-40 Mini Receiver (PDF) T-Match ATU (antenna tuning unit) TR1001 868.35 MHz Hybrid transceiver schematic Transverter for Converting SSB CB to LF for Thru-the-Earth Voice Communications Two Diode Odd-Order Multiplier Two Transistor Reflex Radio TX Module Combiners (copied from commercial circuits) UHF Preamplifier covers 450MHz - 800MHz based on MPSH10 / BF180 / BCY90 Universal USB digimode interface supports CAT (Yaesu), CI/V (Icom) and RS-232 (Kenwood) units (PDF) USB / CAT (CI-V) adapter tested with FT-8900, FTB-9800, VX-7R, VX-7, FT-817 and IC-706MkIIG Variable Bandwidth CW Filter Variety of receiver converter projects Very Simple ADSB Receiver using a TV tunder to allow reception of aircraft transponders VFO from 2001 ARRL Handbook, page 14.20 VFO from 2001 ARRL Handbook, page 17.74 VHF 6 Meterband RF amplifier VHF receiver converterer VLF radio receiver schematic VLF Upconverter for Shortwave Receiver Wave Bubble - A design for a self-tuning portable RF jammer Wave Bubble self-tuning portable RF jammer Wee Willy 75 Meter DSB Transceiver Project Wideband SWR meter Wideband VHF/UHF/SHF 22dB RF preamp with MAR-6 or MAR-8 (MSA-0885) WLW 500KW Transmitter Schematic Yaesu band decoder schematic Yaesu FT-736R doppler compensation Solar-power schematics 12 Volt 20 Amp Solar Charge Controller 1381 solar engine AA Battery Solar Charger AA battery solar charger Buck Mode Switching Regulator for Solar Applications Build a DIY solar iPod charger Converter that enables long cable wiring for pyranometer LED7 solar tracker Measure solar radiation on an Ubuntu Server Photovoltaic Solar Battery Regulator and Load Controller Portable solar battery charger Remote Solar LED light SCC2 10 Amp Solar Charge Controller SCC2 10 Amp Solar Charge Controller Self Powered Solar Box Furnace Sensor Electronic Tracker with H-Bridge Drive Sensor Electronic Tracker with Simple Solar Charge Controller Shunt-mode Solar/Wind Charge Controller Solar cell battery charger circuit diagram Solar cell Nicad charger using Maxim MAX639 Solar charge controller Solar charge controller based on a PIC microcontroller including schematic and source code Solar Charged LED Flashlight Solar energy meter Solar Panel Charge Controller / Low Voltage Disconnect Circuit Solar Panel Charge Controller / Low Voltage Disconnect Circuit Solar Panel Charge Controller / Low Voltage Disconnect Circuit (SPC1) Solar Panel Current Meter Solar Panel Current Meter Solar Powered Garden Light with PCB layout Solar Powered Night Light Solar Powered Reading Lamp Solar robots Solar station for insolation measurement with Ubuntu server 7.10 and a 24-bit Delta-sigma converter Solar switching regulator as published in Silicon Chip Magazine January 1994 Part 1/2 (PDF) Solar switching regulator as published in Silicon Chip Magazine January 1994 Part 2/2 (PDF) Solar Tracker Solar tracker Solar tracking control system SPC2 6 Amp Solar Power Center SPC2 6 Amp Solar Power Center SPC3 9 Amp in / 10 Amp out Solar Power Center Zener-based solar engine Telephone and intercom related schematics 1-line telephone status indicator powered from a 3V battery (PDF) 4-line telephone status indicator that is polarity independent (PDF) 8-line intercom system using 89C51 microcontroller 900MHz cordless phone bug Assorted telephone circuits (ring generator, in-use indicator, audio interface) Audio Visual Indicator for Telephones Build your own radio controlled switch from a cordless telephone Caller ID decoder (requied Postscript file viewer and/or Ordcad schematic capture) Cellular Phone calling Detector Cellular Phone calling Detector Cellular Phone calling Detector Cellular Phone calling detector (detects RF field) Cellular Phone Jammer RF Amplifier circuit diagram Cellular Phone Jammer. Ver 2 circuit diagram Cordless phone backup power source using LM317L Cut Phone Line Detector Cut Phone Line Detector Cut Phone Line Detector Cut phone line detector Cut telephone line detector Detecting a telephone ring signal Digisound ring modulator Digital/Standard Phone Line Tester DSL / ADSL phone line filter FM Telephone Bug FM Telephone Bug FM Telephone Bug FM telephone line bug transmitter (88MHz to 94MHz) GBPPR Cellular Phone Jammer Exciter schematic diagram Greek telecard reader GSM-900 Mobile Jammer Book (PDF compressed with WinRAR) High Power 800 MHz/AMPS Cellular Phone Jammer High Quality Intercom using LM380 amplifier IC Hold function for Telephone Home made PBX / PABX Homebrew P2JBZ-style cellular / mobile phone jammer circuit Incoming call indicator (ZIP file) Isolated Telephone Interface Isolated Telephone Interface (phone tap) for tape recorder, PC sound card etc Line in use indicator that handles two independent phone lines (PDF) Low cost intercom using transistors Off line Telephone tester PCS Cellular Phone Jammer circuit schematic PCS Phone Jammer circuit diagram Phone "Hold" With Music Phone Broadcaster / telehone bugging device circuit diagram Phone Busy Indicator Phone Busy Indicator Phone Busy Indicator Phone call interceptor to stop unsolicited phone calls Phone In Use Indicator circuit diagram Phone in-use (manually activated) Phone In-Use Light Phone line in use indicator Phone line indicator Phone line to audio interface Phone Off-Hook Indicator using CD4049 hex inverter 'phone rang' indicator light Phone to audio interface for SSI202 input Phone-In-Use indicator Portable AMPS Cellular Phone Jammer Portable AMPS Cellular Phone Jammer - Dual Purpose Portable GSM900 Cellular Phone Jammer Portable PCS Cellular Phone Jammer circuit schematic Remote Telephone Bell Ringer Ringing Phone Light Flasher Ringing Phone Light Flasher Ringing Phone Light Flasher using optocoupler and relay Self-powered phone messenger based on a PIC16C819 microcontroller Simple alarm with telephone dialler interface Simple circuit to connect telephone equipment to audio mixer Simple intercom Simple Phone Tap Simple Phone Tap Circuit Simple Phone Tap circuit diagram Simple Skype VoIP analog adapter Simple speakerphone Simple telephone line tap for intercepting telephone calls Single-Wire-Telephones for caves and mines Smart Phone light Soft Musical Telephone Ringer Soft musical telephone ringer Talking phone dial monitor (PDF) Taxi phone automatic dialler Telephone amplifier Telephone amplifier Telephone auto-dialler (useful for an alarm dialler) Telephone call screener with voice Telephone Hold Button Telephone Hold Button Telephone Hold Button circuit Telephone in use light Telephone Line Filter / Protector Telephone Line Monitor Telephone line monitor Telephone line monitor Telephone line simulator Telephone line simulator ideal for testing phone interface projects Telephone music on hold interface Telephone privacy adapter Telephone Record Control using 2N4360, 2N2222 and 2N2102 Telephone Recorder Telephone Recorder Telephone recorder to record phone conversations automatically Telephone ringing circuits The 89C51 PABX The Link 4+0 - Internal Intercom (Doesn't offer external line access) The Link A2B+1 (the Link Telephone Intercom - DTMF version) The Original 2 Phone Intercom Link Design Universal telephone hold Use old telephones as an intercom Wireless Telephone Bug Test equipment circuit diagrams 10Hz - 100KHz D.D.S. Function Generator 2.5 GHz Frequency counter -20 dB Couplers for use with a with a spectrum analyzer or other sensitive detector -20 dBm, 14.060 MHz Precision Signal Source 20kV Digital High Voltage Meter 220V live wire-in-wall scanner 250MHz RF Generator with 1kHz display resolution 3 in one tester (audio, tone generator, diode/circuit tester) 555 go / no-go tester 555 Timer IC Tester 5Hz to 500KHz frequency meter AD9850 DDS daughterboard Alarm circuit to remind you to turn off your DMM (digital multimeter) Amplified field strength meter / RF sniffer Audible Logic Probe based on LM339 operational amplifier Audio Millivoltmeter Audio Millivoltmeter Audio Test Oscillator Automatic heat limiter for soldering iron Battery Tester for 1.5 and 9V BCD readout frequency counter Beeper to find short circuits Beeper to find short circuits (continuity tester) Build an inexpensive Hall effect Gaussmeter Capacitance meter Capacitance meter - precision meter for small capacitors Connection tester for checking solder joints and other connections Conrad Electronics MM3610D multimeter cable pinout Contactless Mains Voltage Indicator Contactless Mains Voltage Indicator Continuity tester Continuity tester 2 Continuity Tester based on 4 x 2N3904 and 1 x 2N3905 transistors Continuity tester using transistors Crystal tester Crystal tester that covers a range of 32kHz to 24MHz DCC Ammeter using ZXCT1009 current monitor DDS from 1-60 MHz with built-in amplifier and variable output level using Analog Devices AD9851 Design for a slightly more expensive Gaussmeter Digital SWR / Power Meter Digital voltmeter (DVM) Digital Voltmeter using ICL7107 Digital Wattmeter, measures from nanowatts to kilowatts using AD8307, PIC16F876, LCD Display Dip Oscillator for HF Distortion Analyser Distortion Analyser Elecraft XG2 receiver test oscillator (PDF) Electric field & leakage detector Electronic Circuit for Crystal Parameter Measurement EMF field probe (electromagnetic field probe) covering up to 100kHz ESR Meter Exclusive 2.5 GHz Frequency Counter with Blue 2x16 LCD display Field Strength Meter (FSM) covers 2Mhz - 1Ghz with peak reception at 3-200Mhz Field strength meter for the 137 kHz band Fixed Frequency "Tuner Dipper" Fluke 8010 / 8012 Interface Frequency and capacitance meter Frequency Counter / Timer / Logic Tester Frequency counter based on PIC16F628 and LCD display Frequency counter measures to 2.5 GHz and offers LCD display Full Featured Transistor Tester Function generator based on 555 timer and three 2N2222 transistors Function generator based on 8038PCD function generator IC Function generator based upon 8038 waveform generator IC Ground Fault Indicator Heathkit signal generator user manual and circuit diagram High Impedance Voltmeter High Resistance Voltmeter Highly sensitive and selective Field Strength Meter system Homebrew signal generator tunable from 3 to 30 Mhz Improved DCC Ammeter (2009) using Zetex ZXCT1009 current monitor In-circuit electrolytic capacitor checker In-circuit electrolytic capacitor tester Inductive meter adapter to measure inductance using a frequency counter Isolated oscilloscope probe Latching Continuity Tester to help find intermittent faults, has quite a few innovative features Latching continuity tester using 4093 LC meter with LCD display for readout LCD Frequency Counter LCD frequency counter (PIC16F84) Led display digital Voltmeter using ICL7107 Line Output / Flyback transformer tester Linear Resistance Meter Linear Resistance Meter Linear scale analog watt meter / RF power meter Linkwitz Cosine Burst Generator Live line detector Logic probe Logic probe Logic probe based on CMOS 4001 chip Logic probe with 7-segment display based on 74LS00 and 74LS47 Logic probe with pulser Low Power Antenna Analyzer and ATU Tuning Aid Low-Cost Phase Noise Measurement Microphone Circuit Test Oscillator Microphone Circuit Test Oscillator Microphone polarity tester circuit diagran Mini DDS (direct digital synthesizer) using an Analog Devices AD9832 (12MHz maximum frequency) Mini oscilloscope based on PIC18F4620 and standard 16x2 text LCD display module Mini tester: Handles continuity testing, resistor testing, capacitor testing and diode testing Miniscope - simple all-valve 1-inch CRT oscilloscope MOSFET tester for N-type MOSFET transistors MOSFET transistor tester Multi wire cable tester that handles up to eight conductors Multi-trace scope display that allows up to 4 channels to be viewed on a single oscilloscope channel Opamp Design and Test Board Optical ballistic chronograph for measuring projectile velocity Oscillopscope triggering circuit for recording long transients at fast sweep speeds (PDF) Oscilloscope / Logic Analyzer based on an Arduino Oscilloscope testing module (huntron circuit) Oscilloscope testing module (Huntron circuit) that shows Lissajous patterns Panel Mounting Radio Frequency Counter PCB board tester and RF detector circuir diagrams Philips SB-6668 frequency counter upgrade PIC based frequency counter PIC logic probe with pulser PIC16F84 based diode tester Picoammeter circuit schematic with 4 ranges using CA3420 Pink Noise Generator for Audio Testing Poor man's frequency counter Precision audio millivoltmeter Precision Frequency Marker Precision VXO for Crystal Characterization & Matching Pulse Reading Logic Probe Pulse Reading Logic Probe Quickie servo tester for testing servo motors (based on Atmel AT90S2343) RCM710 electronic scale, technical manual including schematic Resistor decade box Return Loss Bridge RF field strength meter RF Power Meter for the QRP measures up to 25 watts RF probe circuit diagram and Autotrax PCB layout Schematics and C code for a 0-5V PIC LCD volt meter Schematics and C code for a PIC frequency counter operating up to about 50 MHz (7 segment) Schematics and C code for a PIC frequency counter operating up to about 50 MHz (LCD) Self Oscillating Amplifier for Distortion Testing Self-powered Fast Battery-Tester - Tests 1.5 to 15 Volt cells Sensor to display, built with thermistor, 12-bit ADC, 89S52 and LED display Service monitor / deviation meter circuit Servo Motor Test Circuit (LM555) Signal Tracer and Injector Simple diagnostic tool for use on repeaters in the field Simple electronic S meter Simple Frequency Counter Simple Ground Loss bridge for Ground Loss Measurement at LF Simple Inductance Meter Simple light sensor adapter for oscilloscope Simple Ph Meter Simple pH Meter Circuit, A Low Cost Adapter for Your Digital Voltmeter Simple polarity detector Simple Polarity Tester Simple test equipment to build Simplified Measurement of Output Impedance for Audio Circuits Single chip digital voltmeter using ICL7129 Soft Power On Tester for Amplifiers Sound pressure level meter Spectrum analyzer Mk 1 Spectrum analyzer Mk 2 Standalone LED tester Stereo Test Tone Generator Stereo Test Tone Generator Superprobe handheld test device based on a PIC16F870 SWR Bridge 1 to 1000 Mhz (1GHz) TDR cable reflection tester (Time Domain Reflectometer) TDS/PPM Meter for measuring of the amount of salts in a solution The ESP SIM (Sound Impairment Monitor) The u-counter, a PIC based programmable frequency meter (PDF) Thermistor Thermometer: LCD version Time Domain Reflectometer (TDR) TinyScope - simple all-valve 1-inch CRT oscilloscope Transistor Tester Transistor tester using 555 timer and 4027 Triple Stroboscope True RMS Watt Meter TTL pulse counter/logic probe TTL Pulse Reading Logic Probe TXTVb - 70cm ATV Test Generator (PDF) UHF signal generator Ultra-simple Voltage Probe Ultra-simple voltage probe Universal frequency counter & voltage meter UTP Cable Tester VCR Tuner Based RF Spectrum Analyzer Schematic VHF signal generator Wide dynamic range Field Strength Meter mark I Wide dynamic range Field Strength Meter mark II Wire tracer Wire Tracer (Receiver) Wire Tracer (Transmitter) Wireless Frequency counter XTal Tester for testing quartz crystals based on a pair of BC550C PNP transistors Z80 controlled Viscometer project Zener diode tester based on a 555 timer Timing and oscillator circuits 10MHz GPS disciplined frequency standard 24" Wall Clock 28 LED clock timer 3 - 12 MHz Signal Generator 5 to 30 Minute Timer 555 Timer Tutorial + Circuits A GPS receiver based frequency standard AD9852 DDS schematic AF variable frequency generator using 555 IC Alarm clock based on Atmel AT89C2051 and Dallas DS1307 RTC chip Astable 40KHz clock Astable Multivibrator Astable Multivibrator Projects / Circuit diagrams Audible timer that can be used as a cooking timer for roasting peanuts for example Bedside lamp timer Binary clock Binary clock using LED matrix to display a binary clock with 6 digits of 4 binary bits each Build A 100Khz Crystal Calibrator Build a synchronous clock locked to the mains frequency CA4060B Timer Circuits Cheap 40KHz clock using one gate of a 74C14 Clock divider Clock doubler Clock generator CMOS oscillator using 74C14 inverting Schmitt trigger Collection of timer circuit diagrams to generate very long delays Constant Reactance Voltage Controlled Oscillator (PDF) Continuous Coverage V.F.O. for H.F. (PDF) Countdown timer with relay Crystal 32.768KHz CMOS Oscillator Crystal heater / temperature stablization circuit (TXCO) Crystal oscillator using a CMOS or HCMOS inverter Crystal switcher using diodes D Flip-flot one-shot circuits (PDF) D.I.Y. Clock Oscillator based on 555 timer DCF-77 PIC LED clock (DCF77 is the name of a German radio station on 77.5 KHz) DCF77 PIC16F84A Single-Nixie clock (DCF77 is the name of a German radio station on 77.5 KHz) DDS oscillator based on an Analog Devices AD9859 and an Atmel ATmega16 microco (Microsoft Word) DDS using AD9835 DDS/PLL based VFO synthesizer Decimal DDS Signal Generator Digital clock based on 74 series logic Digital clock that receives and displays the time from the Rugby MSF radio transmission (PIC16F877) Digital Clock with Alarm Using DS1307 Digital Stopwatch 0-60sec Digital Stopwatch 0-99sec Digital timer with 7-segment display and pushbuttons Direct Digital Synthesis VFO for HF Bands - based on Analog Devices AD7009 DDS (PDF) Divide by 1.5 counter (PFD) Egg timer Equivalent circuit and SPICE model of 555 timer Experimental Base Bias Tuned VFO Experimental DDS frequency synthesizer uses the AD9851 Extended counter using CD4017 Frequency Tripler using the CA3028 (PDF) Function Generator Sine / Triangle / Square / Saw / Burst Sweep Noise based on PIC16F870 Giant nixie clock GPS-based universal clock generator HCMOS Gates Make Frequency multipliers (PDF) High Precision GPS/TV controlled Reference Oscillator High-output square wave generator (PDF) Homemade scope clock using a DG7 tube and a Microchip PIC16F876 IC oscillator 1...30MHz using 74LS04 chip Ice Tube Clock - Vacuum fluorescent display (VFD) clock LED matrix clock Line powered 60Hz clock generator (PDF) Long duration timer using 4060 12-stage binary ripple counter Low Distortion Crystal Oscillator (PDF) Micropower pulse generator (PDF) Micro-power pulse generator (PDF) Mixer VXO circuit diagram Monostable multivibrator NE555 Basic Monostable Op Amp Triangle-Wave Generator circuit diagram and SPICE simulation files Oscilloscope CRT Clock Panel-mounting clock PCB exposure countdown timer based on an Atmel ATtiny2313 Photo timer circuit using NE555 PTT Delay Circuit Push Button Switch Debouncer 'Rounding Off' a square wave Selection of 14 oscillator circuits include sinewave, audio, logic and LED flashers Sidereal clock project with circuit diagrams Signal Frequency Beat Frequency Oscillator Simple AF-oscillator / signal generator using pair on 2N2222 transistors Simple Divide-By-N using 161 series chip (PDF) Simple Function Generator using TL084 or other opamp Simple GPS Stabilised 10 MHz Oscillator Simple Sine Wave Oscillator including a PCB layout Single-digit Nixie clock Sleep Timer Special Function Timer Circuits (LM555) Square wave oscillator using CMOS 4011 NAND chip Square wave to sine wave converter Sun tanning timer Super VXO Switch debounce using 555 Time Delay Relay using 4011 CMOS NAND gate Time Delay Relay using 555 timer Timer circuit based on a 14536 and 4011 CMOS chips that can be calibrated using a frequency counter Tiny Crystal Oscillator using LP2980 (PDF) Triangle / Square wave generator Triangle / Squarewave Generator using a 1458 dual opamp Tuning VFOs With A PN-Junction TV based Receiver for a Standard Frequency Generator Two nixie display clock Unusual frequency dividers (PDF) VCO - Voltage Controlled Oscillator covers around 70-210 MHz VCO covers 300MHz to 500MHz based on Maxim MAX2608 VCO VFD (vacuum flourescent display) clock Weston Voltmeter Clock Wide-swing Variable Crystal Oscillator Wien Bridge Oscillator with SPICE simulation Transmitter schematics (also see RF) 1 Watt AM transmitter for the 10 meter band (28MHz) 1.5 volt FM transmitter 1.5 volt tracking transmitter 1.5V tracking transmitter 10W 2M CW transmitter 12-meterband QRP AM oscillator transmitter using a 2N2219 transistor 1300MHz - 1500MHz transmitter with 20 - 50mW output power 144.000 Mhz CW Transmitter 15 watt FM transmitter 15 watt FM transmitter 175KHz inductive pulse transmitter (PDF) 2 Transistor FM Voice Transmitter 3 Watt FM Transmitter 30-Meter QRP Transmitter for Morse Code 3-3.5 Watt FM Transmitter 4 Transistor Tracking Transmitter 4 Watt FM Transmitter 4 watt FM transmitter 4 watt FM transmitter 40 Meter, 5 Watt QRP Transmitter 433MHz super remote control using a PIC12F683 to boost range 433MHz transmitter using SAW resonator 4-transistor transmitter 50 MHz crystal controlled audio bugging device 500kHz Transmitter design 500mW AM transmitter for the 20 meter band (14MHz) 500mW FM PLL transmitter 88-108MHz 5W Chinese PLL FM Transmitter With LCD Printed Circuit Board (PCB) 7MHz QRP transmitter 80 Metre CW beacon / transmitter circuit diagram 80 Metre DSB Transmitter 80m ceramic resonator VXO CW transmitter 88-108Mhz FM Radio Transmitter with 3 transistor stages A 3m (100 MHz) small bug (ZIP file) AM FM Simultaneous Transmitter Using Digital IC (CD4001) AM transmitter AM Transmitter AM Transmitter AM transmitter using no power supply AM/FM Simultaneous Transmitter Using Digital IC BC547 80M SSB QRP Transceiver Coilless FM transmitter using CD4069 CMOS hex interverter chip Cordless telephone bug Crystal controlled transmitter (46.515MHz, 1 transistor FM) Crystal controlled transmitter (46.515MHz, 3 transistor FM) Digitally controlled FM transmitter with 2 line LCD display Europa30, a 10MHz QRP TX FM audio bug using BC817 and BRF92 FM Beacon Broadcast Transmitter (88-108 MHz) FM Microphone micro-transmitter that is small and sensitive FM Microphone transmitter / FM buf circuit diagram FM telephone transmitter FM transmitter FM transmitter based on Colpitts oscillator design FM transmitter bug FM transmitter for bird listening FM Transmitter using two transistors FM Transmitter with range of about 300 feet FM Voice Transmitter FOX BOX - Transmitter controller Ipod Stereo FM transmitter with 1W output power KMDTA Wireless Motion Detector Transmitter Kit Light sensing RF transmitter Long range FM transmitter using 2N3866 for output stage Low Power FM Transmitter Low Power FM Transmitter Low Power PLL FM Transmitter based on LMX1601 and Atmel ATtiny2313 or AT90S2313 microcontroller Medium range transmitter circuit Medium range transmitter using pair of 2N3904 transistors Micro Power FM Broadcasting Circuits Micro-Spy with FETs Micro-Spy with TTL Micro-Spy with USW Miniature FM Transmitter Miniature FM transmitter Miniature FM Transmitter #1 Miniature FM Transmitter #2 Miniature FM Transmitter #3 Miniature tracking transmitter MW Transmitter can be used as an inter-room radio telephone One transistor FM transmitter / FM bugging device One Valve CW transmitter PLL based bug transmitter Pocket APRS (GPS Position) transmitter Pocket Transmitter that can cover 20 to 25 meters with a telescopic antenna Powerful AM transmitter QRP transmitter circuit diagrams Remote RF transmitter based on PIC12F675 or PIC12F629 RF/SS Handie Hopper Transmitter Schematic Sensitive FM Transmitter Sensitive FM transmitter simple 430MHz band FM transmitter uses only 2 FETtransistors Simple CW transmitter for 80M Simple RF transmitter Single transistor FM transmitter Small FM Transmitter Small FM transmitter using SMD components Small radio transmitter Small Radio Transmitter THE FOX - 250mw transmitter with timer THE FOX - 40 milliwatt transmitter THE FOX 750 - 750 milliwatt transmitter Tiny FM transmitter using SMD (surface mount devices) Tracking transmitter Tube Transmitter with 5763 power amplifier Two transistor FM transmitter / FM bug Two transistor FM transmitter circuit diagram and PCB layout Two Valve 40m CW Transmitter Wireless FM Transmitter Wireless microphone Wireless transmitter for PIR using Holtek HT12E Video related circuit schematics 23cm FM ATV Platinum Receiver (PDF) 8 x 8 Audio-video switch An automated, self-recording surveillance camera using an SD memory card for recording digital video Apple IIe RGB to CGA AVR (AT90S2313) composite PAL colour bar generator Camera switching circuit to run multiple cameras with one monitor Circuits to transmit and demoludate RF / video signals over fibre optic cable Closed-Caption Decoder Commodore 64 Video Modulator 251025 Schematics Commodore 64 Video Modulator 251696 Schematics Commodore RF modulator Decoder for encoded transmissions in Videocrypt and D2MAC Generate composite color video signals in software using an SX microcontroller Generate video signals in software using PIC Homebuilt video digitizer Mark I Homebuilt video digitizer Mark II LH0032 video amplifier LM359N video amplifier Low cost video motion detection using a PIC16F819 and an LM339 Macrovision removal Motorized Video Camera Mount Motorized Video Camera Mount PIC micro frame grabber (TDA8708) PIC PAL Video Library including source code and circuit schematics Pico OSD, a PIC video superimposer PIC-Tock video clock RGB pattern generator based on an Atmel ATtiny2313 running at 20MHz Run video and camera power up to 2000 feet over ordinary four conductor telephone wire (PDF) Simple AV (audio / video) wireless transmitter S-video to composite video adapter S-Video to RCA adapter Television signal amplifier TV RGB signal output from a SVGA graphics card TV Signal Amplifier covers frequencies from 40MHz to 900 MHz TV Transmitter - VHF band TV transmitter using negative sound modulation and PAL video modulation TV video transmitter using LM1889 TV/Radio antenna cable galvanic isolator VGA converter for video projectors and fixed frequency monitors VGA to BNC Adapter (Converter) VGA to PAL and NTSC converter VGA to RGB + composite sync -converter VGA to SCART adapter VGA to TV conversion circuit VGA to TV converter VHF/UHF TV modulator Video Activated Relay Video amplifier Video Clock Superimposer Video clock superimposer using PIC16C711 Video DVM - Display voltage on a TV - based on Atmel AT90S1200 and generates vid signal in software Video Signal Amplifier Video signal amplifier circuit Video signal edge enhancement Video Stabilizer/MacroVision Removal Video switcher - run up to four cameras into one video monitor (PDF) Video switcher to allow monitoring of multiple video cameras using a single monitor Video/Audio Wireless Transmitter YBox2 - DIY networked set-top box that connects to a TV to deliver Internet content