E-Mail: csn@telkom.net
Phone: (0355)398952
Fax :    (0355)398736

Dirgantara Telecomunications
Jln. Brantas 23 LK IX Ngunut
Tulungagung 66292
Indonesia
 
 
 
 
 
 
 
 
 


 		  

 

Alarms and security related schematics

  • Intermittent alarm generator
  • Burglar alarm
  • Moisture alarm
  • Fridge door alarm
  • Ultrasonic remote control & alarm system
  • Proximity alarm
  • Electronic lock
  • Door knob alarm (PDF)
  • Water seepage alarm (PDF)
  • Micro-power over temperature alarm (PDF)
  • Personal silent alarm system
  • 5 Zone alarm circuit
  • Miniature loop alarm
  • Gate alarm circuit
  • Perimeter monitor
  • Digital combination lock
  • Touch activated alarm system

    Audio filter schematics

  • Active 2nd Order Filters
  • RC Notch Filter (Twin T)
  • 3KHz low-pass filter plus audio amp (PDF)
  • "A" Weighting Filter For Audio Measurements
  • Multiple Feedback Bandpass Filter

    Audio power amplifier schematics

  • 100W Amplifier
  • 18W Audio amplifier
  • 25W MOSFET amplifier
  • Headphone amplifier
  • Portable headphone amplifier
  • 2W amplifier
  • 8 watt audio amp
  • 20W Amplifier
  • 50W Amplifier
  • Two transistor audio amplifier
  • Personal stereo audio amp
  • Headphone amplifier
  • 1.5W Audio amplifier
  • Low-level audio amp
  • 10W amplifier
  • 80W amplifier
  • LM383 12V Amplifier
  • 100W Audio amplifier
  • 100W RMS Amplifier
  • 2-Channel Power Amplifier
  • Push-Pull Class A Amp using type 5687 dual triodes
  • Push-Pull Class A 2A3 Stereo Amp
  • Single Ended Class A2 SV811-10 Stereo Amp
  • Audio amplifier output relay delay
  • HeadBanger Headphone Amp
  • 2W Amplifier
  • TDA2030 8 Watt amplifier
  • 16 Watt amplifier
  • 8 Watt amplifier
  • 20 Watt Class-A Power Amplifier
  • El-Cheapo - A Really Simple Power Amplifier
  • Single Chip 50 Watt / 8 Ohm Power Amplifier
  • Hi-Fi Headphone Amplifier
  • 100W Guitar Amplifier
  • Death of Zen (DoZ) - A New Class-A Power Amp
  • Soft-Start Circuit For Power Amps
  • Thermo-Fan To Keep Your Amp Cool
  • Audio Amp Output Power Limiter
  • 55W (Originally 75W) Power Amplifier
  • 300W Subwoofer Power Amplifier
  • 20 Watt / Channel Stereo Power Amplifier

    Audio preamp circuits

  • Phono preamp
  • Microphone amplifier
  • RIAA phono amplifier
  • Simple microphone preamplifier
  • Phono Preamp
  • Simple microphone preamplifier
  • ECM Mic preamp
  • Hi Fi preamp
  • Electret mic amplifier
  • Audio preamplifier
  • Audio preamp
  • Low impedance microphone amplifier

    Automative, car and motorcycle schematics

  • Analog Tachometer for Gasoline Engines
  • Headlight On reminder with Light
  • Flashing High Intensity LED 3rd Brake Light
  • Car clock
  • Car message display
  • Car interval wiper
  • Safety indicator light
  • Speed limit alert
  • Portable CD Player Adapter For Car
  • Car battery charger
  • Wireless Auto Tachometer
  • Electronic auto stethoscope
  • Turn signal alarm
  • Motorcycle turn-signal system
  • Cigarette lighter 9V adaptor
  • Headlight reminder
  • Breath Alcohol Tester controlling a car ignition system
  • Parking sonar
  • Simple Car Preamplifier and Artificial Earth
  • Interface between GM's 5 Volt 8192 baud ALDL data stream and a PC serial port
  • 3rd brake light
  • 12V to 9V car coverter
  • Car Nicad charger
  • Economy radar detector

    Data acquisition and data logging schematics

  • TempSentry temperature sensor technical info and schematics
  • Datalogger based on 68HC11
  • Analog input section based on AD9220
  • Light direction sensor
  • 12-Bit ADC interface
  • Digital thermometer
  • Compost temperature and moisture monitor
  • Rain detector
  • Air flow detector
  • Air flow detector
  • Strain gauge sensor
  • Web-based thermometer project
  • Honey Bee counter (PDF)
  • Capacitance type liquid level measurement (PDF)
  • Digital PC Oscilloscope
  • Serial Port A/D-converter
  • Centronics port D/A converters and low-pass filter
  • Water-level sensor

    Games and fun stuff (schematics)

  • Big Mouth
  • GameBoy Camera Parallel Port Interface
  • PSX controler to PC MIDI converter
  • GameBoy Cart Programmer
  • Memory game
  • Project: NES to Atari 2600 controller interface
  • Pine Racecar Victory Judge
  • Electronic coin tosser
  • Electronic craps game
  • First response monitor
  • PowerGlove Interface
  • GameBoy Schematic
  • GameBoy LCD schematic
  • GameBoy Power & Cartridge schematic
  • GameBoy ROM+RAM+MBC1 Cart Schematic
  • GameBoy MBC1 circuit equivalent
  • Super GameBoy schematic
  • Quiz show indicator
  • Bingo!!! (on your tv)
  • Slot car TV cronograph
  • DIT shutterglasses controller

    Infrared based schematics

  • IR remote control system for PC
  • IR Receiver (Amplitude Modulated IR)
  • IR Transmitter for Audio (Amplitude Modulated IR)
  • Universal IR-Remote Lamp Controller
  • IR remote control
  • Infrared body heat detector
  • Stereo IR audio receiver
  • General purpose IR receiver
  • Wireless IR headphone transmitter
  • Wireless IR headphone receiver
  • 40KHz light receiver (PDF)
  • 40KHz TV-VCR repeater (PDF)
  • Infrared remote transponder
  • Build an Infrared night scope
  • Decoding IR Remote Controls
  • IR detector
  • PC IR Remote Control
  • An Ambient-Light-Ignoring Infrared Active Motion Detector
  • IR Ranging
  • Pyroelectric Infrared Sensor
  • Simple IR transmitter circuit
  • Simple infra-red detector
  • IR remote control extender
  • IR remote control tester
  • Infrared repeater
  • 40khz IR Tester
  • 555 timer 40khz IR Oscillator
  • IR detector / emitter
  • Implementing Infrared Object Detection
  • Infrared gate detector
  • Infrared relay with relay output

    Laser related power supplies and data transmission

  • Laser power supply
  • Laser transmitter/receiver
  • Pulsed double-heterostructure laser driver
  • IR Laser light detector
  • Light beam receiver for laser pistols
  • 12V supply for He-Ne laser
  • Laser diode transmitter
  • 20MHz VCSEL 3mW laser test circuit (PDF)
  • 10MHz to 20MHz laser light detector (PDF)
  • Micro-power 40KHz burst laser diode driver (PDF)
  • 40KHz laser burst detector (PDF)
  • Modulated laser diode tester (PDF)
  • Experimental laser data link

    LED related schematics

  • Winking LEDs
  • LED flashing light
  • LED initials
  • 1.5 Volt LED Flashers
  • AC Line Powered LEDs
  • Astable Multivibrator
  • 9 Second Digital Readout Timer
  • 9 Second LED Relay Timer
  • 16 Stage Bi-Directional LED Sequencer, other sequencer and flaser circuits
  • 10 Stage LED Sequencer
  • 28 LED Clock Timer
  • Fading Red Eyes
  • Two Transistor LED Flasher
  • 16 Stage Bi-Directional LED Sequencer
  • Expandable 16 Stage LED Sequencer
  • LED Photo Sensor Circuit
  • LED chaser
  • 7 Segment LED Counter
  • LED Flasher
  • LED pulser with audible output
  • IR Illuminator
  • Flashing Christmas LED display
  • ICL7660 LED flasher
  • 1.5V LED flasher B (PDF)
  • Low current LED flasher (PDF)
  • 1.5V LED flasher A (PDF)
  • Flashing LED advertising badge (PDF)
  • Pulsed LED test circuit (PDF)
  • Low battery voltage flasher (PDF)
  • Adjustable flashing LED
  • LED Mood Light
  • LED Audio VU Meter
  • LM3909 LED flasher
  • Picxie 2 - 8x8 Animated LED Signboard

    Lighting schematics

  • Disco style Strobe Light
  • Varying Brightness AC Lamp
  • 12 Volt Lamp Dimmer
  • 120VAC Lamp Chaser Using Solid State Relays
  • Flashing Neons (NE-51 / NE-2)
  • Sequencing Neons (NE-51 / NE-2)
  • Touch Activated Lamp
  • 220V Flashing lights
  • Coutesy lamp
  • Bedside lamp timer
  • TRIAC light dimmer
  • 12VDC Fluorescent Lamp Driver
  • Strobe light
  • Adjustable Strobe Light
  • 5W Fluorescent light intensity modulator (PDF)
  • 1W Fluorescent lamp night light (PDF)
  • Electronic night light
  • LED Mood Light
  • LX-800 Lighting system
  • Xenon Strobe Light
  • Lamp flasher/dimmer
  • PWM light bulb regulator

    Medical and health related schematics

  • Radiation Dosage-Rate Meter
  • Heartbeat monitor
  • Cranial Electrotherapy Stimulator
  • Automated crib lights
  • Joigging timer
  • Tan timer
  • Muscular Bio-stimulator
  • Pedometer
  • Simple lie detector
  • Heartbeat transducer
  • ECG Amplifier
  • The ESP SIM (Sound Impairment Monitor)

    Microcontroller based schematics

  • Z80 core #1- Z80 CPU and memory (PDF)
  • Z80 core #2- Z80 CTC and SIO
  • Z80 core #3- RS-232 drivers for the SIO
  • RS485-Version of the SAB80C535-Microcontrollerboard
  • PC IR receiver based on PIC16F84
  • AT89C2051/4051scanning 7-segment display and keypad
  • AT89C2051/4051 Driving dot LED
  • AT89C2051/4051stepper motor interface
  • AT89C2051/4051connecting dumb terminal
  • Simple RS232C Level Converter using Transistors
  • C-52 EVB Robot Controller
  • Mains clock controller using AT89C2051
  • AT89C2051/4051 Easy-Downloader
  • AT89C51/52/55 Easy-Downloader
  • PIC16F84 programmer
  • PIC16F84 miniature real-time controller
  • Isolated RS232 for PIC16F84
  • PIC16F84 debugging terminal
  • MiniLOGGER V1.0
  • Atmel 89C Series Flash Microcontroller Programmer
  • AT89C2051 real-time controller
  • PIC12C508 Night-light saver
  • AT89C2051 Night light saver
  • Atmel 8051 Flash Based-Microcontroller Programmer
  • AT89C2051 Digital thermometer and clock
  • 12C508 Smart Lock
  • Build a PIC controlled DDS VFO, 0 to 6 MHz
  • PIC controlled DDS VFO, 0 to 6 MHz
  • TCP/IP stack and WWW server in a PIC16F84
  • PIC16F84 line following robot
  • 50 MHz frequency counter, voltage meter & SWR/PWR indicator
  • Embedded controller based on MC68HC11F1
  • RDS Encoder - digital part
  • Freign vocabulary recollector
  • Embedded system to send e-mails (small TCP/IP stack)
  • Speaking clock using PIC & ISD device
  • Speaking doorbell using PIC & ISD device
  • Whistle detector using 8-pin PIC
  • PIXpand
  • PIC16F84 mechanically scanned clock
  • 68HC11 stepper motor control
  • Serial to parallel converter using the AT89C2051
  • AT89C2051 serial COMs to LED driver
  • 101 AT Keyboard to ASCII Decoder using 68HC705J1A MCU
  • DTMF tone decoder using Basic Stamp
  • A Scenix (and PIC) Programmer
  • Long-period watchdog timer
  • PIC16F84 Range Finder Project
  • Generate video signals in real-time using a PIC16F84
  • PIC Project #1 - RS232 to I2C Interface
  • Dual PIC16C84 prototype board
  • Talking YODA project (PIC16C84)
  • PIC16F84/PIC16F87x-In-System-Programmer
  • Microcontroller interface for 5KW microwave oven
  • PIC16F84 Based Morse Code Reader
  • Interfacing piezo elements to a microcontroller
  • PICADC - a free, PIC based "intelligent" A/D converter
  • AT89C2051 line-follower robot
  • PIC16F84 sound controlled Christmas lights
  • Convenient PIC module
  • Spread spectrum transceiver controlled by PIC
  • 68HC11 based RDS decoder
  • PIC16C84 VT-52 Emulator for Linux
  • Temperature controlled based on AT89CX051
  • 2-wire LCD interface using PIC16CF84
  • PIC16F84 Serial I/O-expander with PicBasic
  • PIC R/C Servo Controller
  • Microprocessor RS-232 Reset
  • A PIC-Based Keyboard Emulator
  • ScanMate audio activated recorded
  • Remote control encoder/decoder with PIC16C620 & PIC12C508
  • Electronic door codelock with PIC16F84
  • Automatic door opener with PIC12C508
  • Infra/radio remote control transmitter/receiver with PIC
  • http://www.vekoll.vein.hu/~jap/electronic/codelock.html
  • Automatic door opener (PIC)
  • Picxie 2 - 8x8 Animated LED Signboard (PIC16F84) Picxie 2 - 8x8 Animated LED Signboard
  • PIC-FC1 Frequency Counter
  • 10 tricks for interfacing to the PIC16C508
  • Interfacing the PIC16C508
  • PIC 5x7 display
  • Analog to digital conversion notes
  • Multi-chip programmer

    Misc audio (also see Music, Amplifiers, Preamp)

  • A Schottky-based Saw-to-Tri converter
  • Saw to triangle converter
  • Improved saw to triangle converter
  • Voltage controllable LFO
  • White noise generator
  • Horror movies sound effects
  • Sound amplifier
  • Temperature sensitive oscillator
  • Old-fashioned siren effect
  • Simple VOX circuit
  • Low Power Op-Amp - Audio Amp (Intercom)
  • 555 Tone Generator (8 Ohm Speaker)
  • 3 Transistor Audio Amp (50 milliwatt)
  • Low Frequency Sinewave Generator
  • Audio level indicator
  • Room noise detector
  • Amplifier timer
  • Bell ring generator
  • Amplified ear
  • Precision audio millivoltmeter
  • A Stereo Digital Volume Control based on the CS3310
  • Voice record/playback using ISD 1000A
  • Audio Graphic Equaliser
  • Analog VU meter
  • Voltage controlled amplifier
  • Audio graphic equaliser
  • Intercom preamp
  • FET audio mixer
  • Microphone mixer
  • Tone control
  • Digital volume control
  • Sound level meter
  • CMOS IC audio oscillator
  • Electronic siren
  • Two-tone siren
  • Underwater microphone
  • Code practice oscillator
  • Noise generator
  • Electronic whistle
  • Very loud beeper (PDF)
  • Digital noise generator (PDF)
  • Condenser microphone hookup
  • Phase shifter
  • Paradoxical Sound Syntheizer
  • Audio line isolator
  • Dynamic microphone to electret microphone input
  • Line level signal to microphone input adapter
  • Simple two line output combiner
  • Electret microphone powering circuits
  • Use amplifier phono input as line level input
  • Speaker signals to line level inputs
  • Spring reverb unit
  • Sine wave generator
  • 3-Band equalizer
  • 6-Input mixer
  • Doorphone intercom
  • Stereo line driver
  • Audio notch filer
  • Peak reading audio level meter
  • Tone control
  • Electronic canary
  • Improved PL tone decoder
  • Magnetic cartridge amplifier
  • LM358 preamp
  • Sound detector
  • Tone detector
  • Tone generator
  • Warbler
  • Voltage Controlled Panner
  • Low Noise Microphone Preamplifier
  • Bridging Adapter For Power Amplifiers
  • Simple Surround Sound Decoder
  • Simplest Ever Amplifier Bridging
  • Stereo Width Controllers
  • Power Amplifier Clipping Indicator
  • Phono Preamps For All
  • Digital Delay Unit For Surround Sound
  • Parametric And Sub-Woofer Equaliser
  • High Quality Sound Mixer
  • Loudspeaker Protection and Muting
  • Direct Injection Box for Recording & PA Systems
  • Minimalist Discrete Hi-Fi Preamp
  • Signal Detecting Auto Power-On Unit
  • Load Sensing Automatic Switch
  • Amplifier thermal protection
  • Active Sub-Woofer and Controller
  • Balanced Line Driver & Receiver
  • VU And PPM Audio Metering
  • Variable Amplifier Impedance
  • Linkwitz Cosine Burst Generator
  • Low Noise Balanced Microphone Preamp
  • Fast Audio Peak Limiter
  • Subwoofer Equaliser
  • Audio output level meter

    Miscellaneous schematics

  • Chaos generator
  • Simple BFO metal detector
  • Electromagnetic Levitator
  • Build Your Own Digital Setting Circles For Your Astronomical Telescope
  • Electric field disturbance monitor
  • Discrete Set/Reset Flip Flop
  • Monostable Flip Flops (one shot)
  • Discrete Bistable Flip Flop
  • Plant watering watcher
  • Capacitance sensor
  • Whistle responder
  • Nocturnal animals whisker
  • 12V DC electronic door chime
  • Random noise generator
  • Hardware random bit generator
  • Analog pulse counter
  • Analog opto-isolator
  • Pulse width modulators (PWM)
  • Pulse width to voltage converter
  • Fantastic Atom Expander
  • Black Light
  • Computerize Your Room/Home
  • Flash slave trigger
  • A Visual CW Zero Beating Aid
  • A two-way Morse practice set
  • Tesla power receiver
  • Basic op-amp circuits
  • Electronic fish lure
  • Ultrasonic sound receiver
  • Experimental data transmitter for fiber optics
  • Experimental fiber optic receiver
  • Ion detector
  • Darkness monitor
  • Electroscope
  • Simple event counter
  • Geiger counter
  • Light detector
  • Short-circuit beeper
  • LM 1800 FM stereo decoder
  • Glitch detector
  • MAX924 bar-graph level gauge
  • Ultrasonic generator
  • Negative ion generator
  • ELF Monitor
  • Supervisory Control And Data Aquisition project (for Home Automation and Security)
  • Ion detector
  • 1uS light pulse descriminator plus F to V converter (PDF)
  • Broadband 2MHz optical fiber receiver (PDF)
  • Modulated light received (PDF)
  • 1uS light pulse receiver plus post amp (MISC)
  • Broadband 5MHz optical fiber receiver (PDF)
  • High-speed light receiver (PDF)
  • Basement doorbell beeper (PDF)
  • Time to dust indicator (PDF)
  • Low-power optical interrupter (PDF)
  • Simple nitrogen spark generator (PDF)
  • Ultrasonic transducer oscillator circuit
  • Build logic gates using discrete parts
  • Jacob's Ladder
  • Variety of quick designs
  • Fogger smoke machine
  • Electric field disturbance monitor
  • Dual comparator forms temperature-compensated proximity detector
  • Electromagnetic field detector
  • Ultrasonic dog whistle
  • An Inexpensive X-ray Machine
  • Magnetic levitation circuit
  • Ultrasonic switch
  • Very basic circuits
  • Bat detector
  • FCTS Project
  • Morse Code Beacon Keyer
  • Lightning Activated Camera Shutter Trigger
  • Electronic Dazer
  • Morse Code Practice Keyer 1
  • Morse Code Practice Keyer 2
  • 741 Light Sensor
  • Fluid level detector
  • Full-duplex doorphone
  • Scaling ADXL50 accelerometer output

    Model and remote control schematics

  • R/C Receiver <-> Joystick Port Interface for Flight Simulators
  • LED traffic lights
  • Two-tone siren
  • HEXBOT robot
  • Alf: The Robotic Matchbox car
  • A Low Cost Thermal Peak Detection Charger
  • A Miniature High-Rate Speed Control with Brake
  • An On/Off Motor Control with Brake
  • 0-10V control for RC servos
  • Simple flashing light circuit
  • Simple flashing light circuit
  • A dual alternating flashing light circuit
  • Simple flashing light circuit
  • A dual tandem flashing light circuit powered by a 9 volt battery
  • Simulate the Gyralite (dual flashing headlights).
  • Simple train detector using ambient light and a photocell
  • Simple charge rate monitor
  • Deluxe charge rate monitor
  • "CLONEPAC" memory module for Futaba 8UAF/8UAP
  • Battery pack discharger
  • Plane locator
  • Plane locator 2
  • Battery low voltage alarm
  • Battery low voltage alarm 2
  • Ultimate battery low voltage alarm
  • Building an RF Remote Control System
  • Two tone train horn
  • Radio Control Battery Backup
  • Glow Plug driver for model engines

    Motor and general control schematics

  • Electronic Thermostat Relay Circuit
  • Interfacing 5 volt CMOS to 12 volt loads
  • Light Activated Relay
  • CMOS Toggle Flip Flop With Relay(CD4013)
  • 555 Timer Monostable Circuit Using Pushbutton
  • Current loop interface
  • Switching solenoid driver
  • Modular relay system
  • Light/dark detector
  • Pulse Width Modulation DC Motor Control
  • Stepper motor controller
  • Touch switch
  • 12V Sump Pump Control
  • Transistor relay driver
  • Latching relay driver
  • Relay delay circuit
  • Touch switch
  • Low voltage DC motor speed controller
  • Flashing neon christmas lights
  • Three input first response monitor
  • Switch-on delay circuit
  • Electronic thermostat
  • LM3911 temperature controller
  • Programmable light-activated relay
  • Pushbutton one-shot and latch (PDF)
  • Charge coupled bi-directional power MOSFET relay (PDF)
  • Finger touch activated switch (PDF)
  • Machine vibration triggers hour meter (PDF)
  • Solid state relay (PDF)
  • Line-powered Xenon flash transmitter (PDF)
  • 9V Xenon photoflash controller (PDF)
  • AC switching with TRIAC from TTL
  • Control 120VAC relay with TTL
  • Driving a relay with a CPU
  • Power-line Appliance Controller
  • Combination-controlled, fully customizable RF remote control
  • Thermoelectic controller (scriptable thermometer)
  • Stepper motor positioner
  • SN754410 Dual Motor Driver Board
  • Temperature monitor
  • Cold activated switch
  • Voltage comparator switch
  • Dark activated switch
  • DC Push Button Motor Control Circuit
  • Light detector
  • Sound operated switch
  • Touch Switches
  • Detect fan failure with a single transistor
  • http://www.rentron.com/SerialServo.htm
  • Constant Temperature Circuit
  • PWM DC Motor Speed Control
  • Solenoid starter
  • CO2 controller for planted tanks
  • Light activated relay

    Music related schematics (also see Audio)

  • Drum machine
  • Simple MIDI-to-CV converter
  • Sounds effects unit
  • ETI 603 Sequencer
  • Synthesizer schematics
  • Peak-reading meters
  • Octave screamer
  • Optical Theremin - electronic musical instrument
  • Spring reverb unit
  • Metronome and pitch generator
  • Mini metronome
  • Simple colour organ
  • Guitar fuzz effect
  • 8 note tune player
  • Colour (Sound) Organ
  • Transisor organ
  • Audible metronome
  • Visual metronome
  • Simple line mixer
  • Simple MIDI tester
  • Electronic metronome
  • Guitar Reverb Pedal
  • Guitar Tremolo Unit
  • Spring Reverb Unit For Guitar
  • Ultra Simple Bass Guitar Compressor
  • Vox AC30 Guitar Amplifier Simulator
  • Guitar Vibrato Unit
  • Musical Instrument (Expandable) Graphic Equaliser
  • D.C. Mixer for music synthesizers

    PC related schematics

  • I2C printer port adaptor
  • RS232C Level Converter
  • Isolated Full Duplex RS232C Interface
  • ISA 8-bit output card
  • PC based 7-segment rolling display
  • Parallel print capture system
  • Modem Rockwell RCV336/ACF model V1433VQR ext.
  • Genius Mouse schematics
  • PC serial port receiver
  • Parallel port relay interface
  • ISA 48 I/O digital card
  • Parallel (Printer) Port Interface
  • RS-232 line monitor and loopback cables
  • A Serial Infrared Remote Controller
  • Interfacing 16x2 character :LCD to parallel port
  • 8254 Timer and Counter Board
  • Serial to ECP interface
  • A PC-Based LowFER Frequency Synthesizer
  • General purpose 48-bit ISA parallel I/O card
  • 4-channel 8-bit analog-to-digital converter for PC
  • Printer port ADC
  • Parallel port ADC based on MAX147
  • Analog Signal Acquisition for PC Printer Port
  • More accurate PC/AT clock
  • Getting power from RS-232 interface
  • Barcode scanner
  • PC thermometer
  • Parallel port servo controller
  • Connect two CD-ROM drives to one soundcard
  • Headphone driving circuit for soundcards
  • Get power out of PC parallel port
  • Null Printer Adapter
  • PC speaker volume control circuit
  • How to get power from PC to your circuits
  • RS-232 surge protection
  • Simple RS-232 serial port buffer circuit
  • Get power out of PC RS-232 port
  • Sound Blaster Microphone Preamplifier
  • Sega 3D glass interfacing circuits
  • Convert Atari-style joystick to PC joystick port
  • Fake Joystick circuit
  • Using the joystick port as general purpose input
  • Connect other circuits to PC joystick port
  • Schematic of a standard PC joystick
  • Simple PC SmartCard reader
  • Fax to modem interface
  • DC-DC Power Supply from car 12V battery to PC motherboard
  • Linux Infra-red Remote Control (LIRC)
  • Compter microphone
  • Laptop Computer Serial Port Power Booster
  • HamComm Interface
  • Hi-Fi PC Speaker System
  • IDE hard-disk interface for Amiga 500
  • Parallel port ADC/DAC
  • Parallel port ADC using ADC0804
  • High speed 20MSPS ADC interface
  • 9-pin null modem cable
  • 24-bit parallel port interface with 8255 for Commodore computer
  • 24-line PC digital interface (PDF)
  • SPDIF-interface to AudioPCI

    PDA interfaces and related schematics

  • SHARP palm-top/hand-held to RS232 serial converter
  • Casio organiser hardware
  • Casio datalogger

    Power supplies and control schematics

  • Power supply provides +5VDC regulated, +10VDC unregulated and 7.5VAC
  • Basic increase in DC voltage
  • Power Tool Torque Control
  • Generating Negative 5 Volts from 9 Volt Battery
  • LED Battery Condition Indicator
  • LM317 Variable Voltage Regulator
  • LM317 Regulator With Pass Transistor
  • High Current Regulated Power Supply
  • Simple Variable Voltage Source
  • Variable 3 - 24 Volt / 3 Amp Power Supply
  • 2 watt switching power supply
  • Variable Voltage and Current Power Supply
  • Low Power DC to DC Converter
  • Constant Current Battery Charger
  • Variable DC power supply
  • Using the 78xx Series Voltage Regulators
  • 6V to 12V Converter
  • Tesla coil / HV generator
  • 12VDC To 120VAC Inverter
  • High Current Power Supply
  • Dual Polarity Power Supply
  • High Voltage High Current Power Supply
  • Transformerless Power Supply
  • Fixed Voltage Power Supply
  • Voltage Inverter
  • Voltage Inverter
  • 1A Variable Regulated Power Supply
  • Negative voltage generator
  • 12V battery capacity tester
  • NE555 Low Voltage Battery Disconnect Circuit
  • 13.5KV power supply
  • Kirlian device supply
  • LM317 adjustable power supply
  • LTC1265 Nicad charger
  • Single cell lithium battery charger
  • Smart battery charger
  • Battery charge indicator
  • Lead acid trickle charger
  • 12B Battery condition indicator
  • Power reminder beeper (PDF)
  • Unplugged power cord alarm
  • Machine power loss beepter (PDF)
  • HV supply: 12VDC in, 12KV out
  • Generating -5VDC from +5VDC
  • Filtering PC bus POWER
  • Bidirectionall power inverter
  • Adjustable power supply using LM317
  • Simple +5V power supply circuit
  • 12V 30A power supply
  • Dual regulated power supply
  • Fuse blown indicator
  • Gyrator circuit
  • Variable power supply
  • Nicad battery charger
  • Regulated 12V supply
  • Unregulated power supply
  • 12 volt battery monitor
  • 12 volt power supply
  • 5 volt power supply
  • Battery voltage monitor
  • LM3914 battery monitor
  • Multiple voltage power supply
  • Voltage doubler
  • Voltage inverter
  • PWM Motor Speed Controller / DC Light Dimmer
  • PWM Motor/Light Controller
  • Low Power LED Voltmeter
  • PWM Motor/Light Controller
  • PWM Motor/Light Controller variants
  • Low Power LED Voltmeter
  • Temperature Controlled NICD Charger
  • Simple Capacitance Multiplier Power Supply For Class-A Amplifiers
  • Simple DC Adapter Power Supply
  • Variable Dual Lab Power Supply
  • Charger for gel lead acid batteries
  • 12V to 120VAC inverter
  • Nicad Battery Discharger/Capacity Indicator

    Radio-frequency schematics (also see Transmitters)

  • CW RECEIVER 40/80 meter CW receiver
  • TRF AM Receiver circuit
  • Receiver building blocks
  • Crystal radio
  • Automatic message sender for CB
  • RF Sensing relay driver
  • Vibrating pocket bug detector
  • 2MHz RF Oscillator
  • 50-150MHz Overtone Oscillator
  • Simple Op-Amp Radio
  • NASA TURFTS - TDRSS User RF Test Set
  • HF Linear RF power amplifier
  • 100W HF Linear AMP
  • 3W FM Transmitter
  • Crystal radio
  • Op-Amp Radio
  • Car radio tunes the Amateur Bands
  • Crystal set that requires no antenna
  • 80m Direct Conversion Receiver
  • A compact L-match ATU for portable use
  • Morse Adaptor for your VHF/UHF FM rig
  • An end-fed antenna, L-match coupler and resistive bridge for HF
  • AM Broadcast Band Regenerative Receiver
  • 50 MHz to 146 MHz Converter
  • Hear Amateurs on your Shortwave Radio!
  • Compact 20 14 MHz direct conversion receiver
  • Hear Amateurs on your FM Radio!
  • RF actuated CW monitor
  • LF to HF Converter
  • Super 80 ultra-simple SSB receiver for 3.5 MHz
  • The MRX-40 Mini Receiver
  • Phase Shift Radio Direction Finder
  • UHF oscillator
  • Economoy short-wave radio
  • Linearized RF detector
  • Two-band radio
  • Shortwave conveter for scanners
  • FM Bug
  • AM Radio
  • Toroidal coil RF shortwave receiver
  • Crystal radio
  • Bug detector
  • 175KHz inductive pulse receiver (PDF)
  • 200-400 MHz voltage controlled oscillator
  • Icom CT-17 Logging & Control Interface Level Converter
  • AM/FM/SW active antenna
  • RF Sniffer <.5 to >500 MHz
  • Frequency Synthesizer
  • Four Channel Wireless Transmitter and Receiver
  • Wireless event receiver
  • Talking receiver
  • Wireless motion detector
  • 418MHz Control RX/TX
  • 2N2222 40 Meter CW/DSB Transceiver
  • AM receiver
  • Field strength meter
  • MW preamplifier
  • Simple field strength meter
  • 4 band double-tuned preselector
  • ZN414 AM receiver
  • ZN414 shortwave receiver
  • Phased lock loop schematic
  • SOP direct conversion receiver
  • Simple UHF dummy load
  • Receiver
  • 30m direct conversion receiver
  • Popcorn direct conversion receiver
  • 40m direct conversion receiver
  • 80m direct conversion receiver
  • R-399-A Communications Receiver
  • 136 kHz direct conversion receiver
  • How to Build a 300MHz AM, RF Remote Control System
  • RF Modem Robotics Project
  • Smooth Tone Clickless CW Sidetone Generator
  • Variety of receiver converter projects
  • One transistor FM receiver
  • 42 Mc Band to 88 Mc Band (retrofit converter) Project
  • 50MHz Assistant (Preamp & Power Amp.)
  • Bug detector
  • Basic RF oscillator
  • Superregenerative 27MHz receiver
  • Radio Control Electric Switch
  • 56K RF Modem
  • 80M ARDF direction finder

    Solar-powered schematics

  • Sun tracking circuit for solar arrays
  • Solar power recharger
  • Solar power supply
  • AA battery solar charger
  • Solar Panel Charge Controller / Low Voltage Disconnect Circuit
  • Solar Panel Current Meter
  • Solar Charged LED Flashlight
  • AA battery solar charger
  • Solar Panel Charge Controller / Low Voltage Disconnect Circuit
  • Solar Panel Current Meter
  • Solar cell Nicad charger

    Telephone and intercom related schematics

  • Phone in use circuit
  • Digisound ring modulator
  • Incoming call indicator
  • Telephone Ring Generator Using 60Hz Power Transformer
  • Telephone Ring Generator Using Switching Power Supply
  • Telephone In-Use LED Indicator
  • Telephone In-Use Relay Circuit
  • Telephone Audio Interface
  • Ringing Phone Light Flasher
  • Phone Busy Indicator
  • FM Telephone Bug
  • Cut Phone Line Detector
  • Simple Phone Tap
  • Telephone Hold Button
  • Telephone Recorder
  • Telephone recording circuit
  • 1-line telephone status indicator (PDF)
  • Line in use indicator (PDF)
  • 4-line telephone status indicator (PDF)
  • Caller ID decoder
  • Telephone in use light
  • Detecting a telephone RING
  • Phone In-Use Light
  • Phone to audio interface
  • Phone Off-Hook Indicator
  • 'phone rang' indicator light
  • Phone Line to Audio
  • Phone in-use
  • Telephone Line Monitor
  • Use old phones as an intercom
  • Phone-In-Use indicator
  • Hold function for Telephone
  • Digital/Standard Phone Line Tester
  • Universal telephone hold
  • Talking phone dial monitor
  • Telephone line simulator
  • Telephone privacy adapter
  • Telephone ringing circuits
  • Simple circuit to connect telephone equipment to audio mixer
  • Cut phone line detector

    Test equipment schematics

  • Tri-Waveform Generator
  • JFET crystal testing oscillator
  • ESR Meter
  • Line Output / Flyback transformer tester
  • AC Line Current Detector
  • Triangle and Squarewave Generator
  • Voltage probe
  • Live line detector
  • Electric field & leakage detector
  • Simple polarity detector
  • RCM710 Electronic Scale
  • 3 - 12 MHz Signal Generator
  • Some simple test equipment to build
  • RF Power Meter for the QRPer
  • Dip Oscillator for HF
  • Two Tone Audio Oscillator (use for SSB tests)
  • Audible continuity tester
  • Wire tracer
  • Signal generator for signal tracer
  • Electronic level
  • Digital volt meter
  • Adjustable continuity tested
  • Simple pH meter
  • Temperature compensated pH meter
  • pH meter with calibration
  • LASER/LED light output intensity meter (PDF)
  • Frequency and capacitance meter
  • Simple light sensor adapter for oscilloscope
  • Time Domain Reflectometer (TDR)
  • EMF field probe
  • Function generator
  • Logic probe
  • Zener diode tester
  • Signal tracer & injector
  • Pulse Reading Logic Probe
  • Pink Noise Generator for Audio Testing
  • Audio Millivoltmeter
  • Audio Test Oscillator
  • Full Featured Transistor Tester
  • Opamp Design and Test Board
  • Microphone Circuit Test Oscillator
  • Distortion Analyser
  • Self Oscillating Amplifier for Distortion Testing
  • Build a Magnetic Field Immunity Tester
  • 555 Timer IC Tester
  • 555 go / no-go tester
  • 12V Lead-Acid Battery Monitor
  • Continuity tester 2
  • Continuity tester
  • Logic probe
  • 220V wiring detector
  • In-circuit electrolytic tester
  • PIC logic probe with pulser

    Timing, oscillators etc. (schematics)

  • Staircase wave generator
  • 1 Second Time Base From Crystal Osc.
  • Power-On Time Delay Relay Circuit
  • Low Voltage , High Current Time Delay Circuit
  • Power-Off Time Delay Relay Circuit
  • Generating a Delayed Pulse With a dual 555 Timer
  • 1KHz Sinewave generator
  • Timed beeper
  • Weign Bridge generator
  • Time Delay Relay
  • Time Delay Relay
  • Wide-swing Variable Crystal Oscillator
  • Circuit that momentarily closes a pair of contacts at long intervals
  • Long period timer
  • 555 time delay circuit
  • Low frequency clock
  • Line powered 60Hz clock generator (PDF)
  • Micro-power pulse generator (PDF)
  • Darkroom camera shutter timer
  • Divide by 1.5 counter (PFD)
  • High-output square wave generator (PDF)
  • D Flip-flot one-shot circuits (PDF)
  • Clock divider
  • Clock doubler
  • CMOS oscillator
  • Crystal 32.768KHz CMOS Oscillator
  • Crystal oscillator
  • Cheap 40KHz clock
  • Stable 40KHz clock
  • 'Rounding Off' a square wave
  • Switch debounce using 555
  • Square wave to sine wave converter
  • Micropower pulse generator (PDF)
  • Push Button Switch Debouncer
  • Square wave oscillator
  • Clock generator
  • 555 Timer Tutorial + Circuits

    Transmitter schematics (also see RF)

  • Portable 40W CW transmitter
  • Spark-gap transmitter
  • Wireless microphone
  • A 3m (100 MHz) small bug
  • Basic FM Transmitter
  • Micro Power AM Broadcast Transmitter
  • FM Beacon Transmitter (88-108 MHz)
  • FM transmitter
  • Two Valve 40m CW Transmitter
  • Frequency agile 80m CW QRP transmitter
  • 80 metre DSB transmitter
  • One Valve CW transmitter
  • Wireless microphone
  • XTAL locked tone transmitter
  • AM oscillator for wireless microphones
  • Wireless microphone
  • 1W CW Transmitter
  • 175KHz inductive pulse transmitter (PDF)
  • Small Radio Transmitter
  • FM Telephone Transmitter
  • Micropower Event Transmitter
  • FM transmitter
  • 4 transistor transmitter
  • FM transmitter
  • Op-amp based FM transmitter
  • Miniature FM transmitter
  • Sensitive FM transmitter
  • Simple RF transmitter
  • 1.5 volt tracking transmitter
  • Tracking transmitter
  • Micro Power FM Broadcasting Circuits
  • Low Power FM Transmitter
  • 30-Meter QRP Transmitter for Morse Code
  • Miniature FM Transmitter #1
  • Miniature FM Transmitter #2
  • Miniature FM Transmitter #3
  • Light sensing RF transmitter
  • Micro-Spy with FETs
  • Micro-Spy with USW
  • Micro-Spy with TTL

    Video related schematics

  • Audio / video distribution amplifier
  • Driver for multiple VGA monitors
  • Closed-Caption Decoder
  • PIC-Tock video clock
  • Video signal amplifier
  • MC1374 based TV transmitter
  • TV transmitter
  • Simple TV transmitter
  • Video signal edge enhancement
  • Video amplifier
  • Digital volt meter with video output
  • Video switcher (PDF)
  • Video switcher
  • TV/Radio antenna cable galvanic isolator
  • S-video to composite video adapter
  • VGA converter for video projectors and fixed frequency monitors
  • VGA to TV converter
  • VGA to PAL and NTSC converter
  • Do-it-Yourself VGA ro PPrPb Cable
  • Many video amplifier circuits includiing transmission over UTP (PDF)
  • Mark II video digitiser
  • Video digitiser
  • Audio-video switch