Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
Liquid Sensing Circuits
Light Sensing Circuits
Voltage Detector Circuits
Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
Free Energy Circuits
AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
Analog to Digital
Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
Voltage to Current
voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
DIY HV Variable Cap
DIY PMA alternator
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Bomb Deactivation Game
"Should I cut the blue wire... or the red...?" This is a very common phrase in many movies when the action hero has a bomb in front of him with little time left and he has to choose which wire to cut and stop the bomb from exploding saving millions of people. This game is just that... a count down timer and 4 wires of different colors. The...
Christmas LED lights circuit with 555 timer
This circuit sequence through a pattern of Christmas lights to turn on and off each string of lights, one at a time. After sequencing through all strings, the circuit turns the last string off, then turns all strings on, and then off, before repeating the pattern. Some simple wiring changes will let you set up other patterns. This circuit...
Halloween game with moving sensor (12F683)
Halloween is coming up and it's time to do some pranks. Everyone likes Halloween and I'm no exception. Every year me and my wife decorate the house with lot's of bugs, spider webs, creepy posters and of course lot's of Halloween candy. While making the normal Halloween preparations I came up with the idea of making a circuit that would make some...
Hand Steadiness electronic Game
The Hand Steadiness Tester is a game which tests the steadiness of your hand. The player has to take the ring from one end to another end without touching it to the wire. In this the player gets 4 turns. If the player touches the wire 4 times he has to reset the game & start the whole game from the beginning. This project consists of IC 4017, a...
LED flashing with 3909 IC circuit
This project uses a 3909 IC and a few other parts; power is 1.5 volts DC.
Hover Board Project
The fan, motor controller and batteries are mounted to the bottom board, so that the fan system can be wired up and tested before assembly. Once the fan system is tested the top board and bottom board can be brought together to form the hovercraft plenum chamber. The segmented skirt attaches between the top and bottom board, to channel the air...
Scoring Game Circuit
You can play this game alone or with your friends. The circuit comprises a timer IC, two decade counters and a display driver along with a 7-segment display. The game is simple. As stated above, it is a scoring game and the competitor who scores 100 points rapidly (in short steps) is the winner. For scoring, one has the option of pressing either...
LED DICE circuit
1. Pressing `Roll` switch. When the switch is turned on T1 is turned off (its base is pulled high by the 3M3) and the 555 oscillator is not oscillating. Pressing the ROLL switch immediately charges the 470nF capacitor, T1 is turned ON and the 555 starts to oscillate. The 470nF gradually discharges via the 10M and 3M3 and turns T1 off....
Quiz contests Jam circuit
This jam circuit can be used in quiz contests wherein any participant who presses his button (switch) before the other contestants, gets the first chance to answer a question. The circuit given here permits up to eight contestants with each one allotted a distinct number (1 to 8). The display will show the number of the contestant...
Everybody likes re-discovering something they did years ago. Here`s a game we all played at school. Possibly under the name of HANG THE BUTCHER. The game is quite simple. One player thinks of a word and writes down the number of letters in that word in the form of boxes or dashes. The object of the game is for the opponent to suggest letters of...
Fastest Finger Indicator
Quiz-type game shows are increasingly becoming popular on television these days. In such games, fastest finger first indicators (FFFIs) are used to test the players reaction time. The players designated number is displayed with an audio alarm when the player presses his entry button.
LED Dice schematic
This project has two advantages over previous dice circuits. It produces a realistic readout as well as a `slow-down` feature. These combine to make it one of our most popular games projects. As can been seen in the photo, the 7 LEDs are positioned on the board in the same positions as the spots on a dice (die). When these are activated, they...
LED Zeppelin game circuit
The name of our game, LED Zeppelin, is a play on words. It comes not from the pop group of the same name but from Graf Von Zeppelin, a German who invented the first rigid air ship in 1900. The association fits perfectly. The game consists of six LEDs and an indicator LED that flashes at a rate of about 2 cycles per second. A push button is the...
LOTTO NUMBER SELECTOR
This project is a real winner in more ways than one. When you understand how the circuit works, it is really 4 projects in one. And it has two modes of operation: MANUAL and AUTOMATIC. Everyone likes a little flutter. The introduction of so many outlets in competition for the gambling dollar is positive proof of this. Every week the total prize...
ELECTRONIC QUIZ TABLE
Here is a simple, low-cost quiz table for four game participants. It determines the contestant who first presses the switch (S1 through S4) to answer a question and locks out the remaining three entries. Simultaneously, the respective audio alarm sounds and the bulb glows. The quiz table can be used for more number of contestants simply...
VCR Pong game
The most amazing thing about this project is the small number of parts. My boss joked that it involves 17 cents worth of parts and 1000 dollars worth of programming. But don`t worry -- the code is free to you! That means you can build this TV pong game in a very short time, or adapt the generic "video engine" portion of the program to make your...
NUMBER GUESSING GAME
This number guessing game is quite simple. In this game the player thinks of any number between 1 and 99. Then he scans the eight groups of numbers given in the eight boxes in the table. Each group corresponds to a specific switch (indicated on the top of each group) on an 8-way DIP switch.
Electronic TIC TAC TOE
This project is not to introduce Tic Tac Toe. Everyone knows this game. It`s to introduce two features. Bi-coloured LEDs, microcontrollers and the skill of writing an ALGORITHM. You can use the project to learn the skills of creating the Tic Tac Toe program or create animations on the 3x3 display.
Fastest Finger First project
If 12V relays are used, you can replace the 180R resistors R7,R9,R14,R16,R20,R22,R26 and R28 with a wire link (the resistors are only there to limit current if you use 5V relays, of which I had a load in my parts bin). If the system doesn't reset cleanly on power-up (several lights may come on or the relays may chatter), just solder a 100nF...
memory game using a PIC
The PC board has been designed to accept either a PIC16F84A or PIC16F628. With the introduction of the`628 to the world market, it has taken over from the PIC16F84A and we will be ceasing to design projects for the `F84 and concentrating on the cheaper `F628. The two main improvements with this chip are the lower price and internal 4MHz...
Circuit improves first-event detector
The circuits in Figure 1 have certain advantages over those in a previous Design Idea (Reference 1). The first-event detector with autoreset (Figure 1a) consists of N sets of monostable multivibrators, using 4001 logic circuits with LEDs attached. After any player (1 through N) presses a pushbutton, the corresponding monostable multivibrator...
Arc Welder Simulator
The arc welder simulator is made up from several functional blocks: five oscillators, two gates and the output driver. IC1A, IC1B and IC1C are all wired as square wave oscillators, each operating at a different frequency under 100 Hz. This output is a pulse of semi-random duration and occurring at semi-random intervals. This is used to generate...
Sega 3D glass interfacing
This documents ties to clear out one method for connecting Sega 3D glasses to PC serial port for cheap PC virtual reality. This who do no not know what those Sega 3D glasses are. Sega designed special glasses for it`s video game console to be able to produce 3D video games. Those glasses used LCD shutter method for producing 3D images. In this...
Electronic Candle Blow Out
This design was developed by request of a correspondent having made a sort of LED candle and needing to switch off the LED with a puff. This simple, easy to build gadget can be useful as a prop for Halloween and Christmas season, shows and the like.
This circuit was designed to provide that continuous light lamps already wired into a circuit, become flashing. Simply insert the circuit between existing lamp and negative supply. Especially suited for car or panel pilot lights, this device can drive lamps up to 10W. Ideal to operate 3 to 24V DC existing on-circuit lamps. LED operation is...
RGB LED PWM Driver
The circuit uses (RGB) Red, Green and Blue high brightness LEDs that are pulse width modulated (PWM) to vary the intensity of each colour LED. This allows effectively any colour to be generated with rapid changing strobe effects, fast and slow colour fades as well as static colours. The data used to set and change the colours is held in an...
Upon opening your fridge door the photocell is exposed to light and the piggy oinks. Reverse engineered circuit diagram is of an early commercial design which uses an OP-AMP to make simulated pig sounds. Modern Fridge Pigs sound much better because they store an analog recording of a real pig in a cmos chip.
This box is a set of nine relaxation oscillators. It blinks random patterns and looks cool. When the voltage on the capacitors charge to 65 volts, the neon gas ionizes and discharges the capacitors to 55 volts. The frequency can be simply calculated from the exponential RC function, assuming that the discharge time is neglible to the charging time.
Race Start Lights
This project provides an simple F1 motor racing style 5 light race start sequence with a random delay that you can use on a real race track, kart circuit or even your slot-car circuit. Operation is simple; when the start button is pressed all the LED clusters are off. They then illuminate sequentially at one second intervals until all five...
Morse Code with touch button (555)
This simple CPO is for those who want to practice Morse Code in a different way, ie with out the morse key. It can be also used as a touch operated door bell. The popular timer IC555 is wired as astable multivibrator. The frequency (tone) can be changed by varying the 100 K variable resistor between pin 7 and 6 of timer IC555. The volume can be...
Morse Code teacher
Morse Tutor is a program written in C++. It can be used for learning or sending morse code. Morse code uses long (dash) and short (dot) sounds to communicate. The dot is the basic unit and the dash is equal to the length of three dot's. Morse Code was developed by Samual Morse in 1897. Due to the advantages like overriding noise, static, use of...
Morse Keyer circuit
This is not a sophisticated automatic keyer but it is lot QRP to build and to have fun operating it. When the paddle is connected to the DOT terminal, C1 starts to charge. When C1's charge reaches sufficiently high value, it causes the transistor BC157B to conduct and pulls the relay and key the transmitter. Paddle connection is then...
555 Timer Circuits
RC Model Toy Circuits
H Bridge Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity