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
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Big Trak Motor Driver Schematic
Schematic of Big Trak`s motor driver circuit. The toy includes 9112 and 9113 transistors (and sometimes 2N6715) because the 75494 chip can`t supply enough current to run the Big Trak`s motors by itself..
Bipolar Transistor HBridge Motor Driver
Schematic, breadboard photo, parts list, and results of several transistor variations on the classic bipolar hbridge motor driver circuit..
Debounced Counter Made From Off-The-Shelf Chips
The real usefulness of the SR latch comes during input switch transitions. Let`s assume the input switch is a break-before-make and the switch starts in the up position. From the prior analysis, the inputs values when the switch is up are low, low, high, high, and the output is high. As the switch is toggled, it breaks the first input, changing it
Dual Fan Controller
Describes reading a thermistor using an Atmel ATtiny45 or ATMega168 microcontroller to drive two fans to cool a PC installed in a kitchen cabinet. Include a table for converting the BC1482 resistance to Fahrenheit..
Simple Robot That Drives Forward and Back
The Flip-Flop Robot drives forward until it hits an obstacle, and then reverses until it hits another obstacle. This back-and-forth process continues indefinitely. By limiting the functionality to this very rudimentary behavior, it can be generated from an off-the-shelf chip instead of requiring a fancy microcontroller. Thus, this is a good robot
Atari Joystick Wired Remote Control for Robots
The simplest solution for implementing joystick control for a robot would be to program the actions in software in a microcontroller. But, since many readers prefer off-the-shelf parts, this circuit is going to be made with diodes, resistors, transistors, and one FAN8200 motor driver chip. The downside is that the circuit is more complex. D10: A S
Constant Current LED Tester
Most of my circuits still use 5 V regulated power for the chips, because 8-bit microcontrollers run faster and some sensors require 5 V. Since 5 V is more than enough for even a white LED, I`m not concerned with the voltage needed by a particular LED in use. However, since my robots are battery powered, I am concerned with the current usage,...
Laser Pointer Remote Control Robot Room
Laser Pointer Remote Control Circuit
The laser-pointer detection circuitry is able to determine when a laser light is aimed at a particular photosensor. If the laser is aimed at the top sensor, the comparator chip outputs on . If the laser is aimed at the bottom sensor, the comparator chip outputs off . The circuit could be considered complete if you wanted somethi
68HC08 PLL Clock Generator
PWM - Pulse Width Modulation for DC Motor Speed and LED Brightness 1
PWM - Pulse Width Modulation for DC Motor Speed and LED Brightness 2
To understand how the 74AC14 PWM circuit works, let`s zoom in on the section of the schematic containing the trimpot, diodes, capacitor, and the first inverter logic gate. The capacitor is empty (discharged) when the power is first applied to the circuit. Because the capacitor is low, and because the capacitor is connected to the input pin of the
PWM - Pulse Width Modulation for DC Motor Speed and LED Brightness 4
PWM - Pulse Width Modulation for DC Motor Speed and LED Brightness 5
LED Pumpkin Candles for Colorful Halloween Jack-O-Lanterns
Discrete blinking LEDs are convenient, but the blink rate and blink duration are not configurable. I tried goofing around with using transistors, resistors, and capacitors to alter the blinking LED. In the end, I had so many extra electronic components that I figured it would be easier to simply program the lighting effect with software. As soon a
Color Sensor from a Reversed LED and Op Amp
One of the first lessons that an electronics student learns is that an LED provides light from current flow. But, did you know that an LED put in backwards provides current flow from light Yes! It`s true. Hook up a high-quality ultra-bright red LED by itself (no battery or other circuitry) to a multimeter in voltage measurement mode. Put the...
Safe Sync to Adapt Digital Camera to Higher Voltage Flash
This circuit adds a datasheet-compliant trigger signal, reversed polarity protection, optional test button, and optional battery operation. U1 L601E3 or MAC97A8 triac. 400 V, 1 A. When U1 is enabled, the + and - wires of the flash are electrically connected, just as though the camera hot shoe had done so. A triac is a semiconductor switch,...
Circuit to Measure Power Supply Voltages
To obtain the power supply graphs on the previous page, I didn`t stand outside for two days straight measuring the power sources with a voltmeter. Instead, the circuit itself is able to independently monitor the power sources with the addition of a few resistors. Although diode D3 allows the solar panel voltage to charge the batteries, measuring t
Building a FRED Photopopper
Building An Infrared Proximity Detector
PICmicro Processor Unit version 2
pololu high current motor driver
Need more current If you`ve got a larger motor waiting to be used, the Pololu High Current Motor Driver Board 14A 6V-16V is just what you need. Connect three digital lines to your microcontroller (five if you want error condition feedback), and you`re ready to go! The Pololu High Current motor driver board is a compact solution for using the...
Build a Light-Tracking Robot Critter
Build a Light-Tracking Robot Critter
LIGHT SEEKING ROBOT
The circuit is light seeking; it will follow a flashlight around a darkened room. A pair of photocells determine the direction in which the robot will move. Each photocell is connected to an op amp configured as a comparator. When sufficient light falls on photocell R2, the voltage at the inverting input (pin 6) of ICl-a will fall below the voltag
Robot control circuit composed of transistor and NE555
Figure 2-33 (a) is the action schematic diagram of the robot closing to the object. When there is no objects in front of the robot, it will go forward in the straight line; when there is an object in left or right side of the robot,it will turn left or right to close to the object. Figure 2-33 (b) is the block diagram to achieve this action....
Remote control robot circuit
The remote control robot circuit is as shown in the figure. The figure 2-36(a) is the circuit diagram, the figure 2-36(b) is the operating timing diagram. The rotation process of the rebot is: in the circuit, the ultrasonic launching circuit is composed of the 40kHz oscillating circuit and driving circuit. The two sensors receive the ultrasonic...
Solar Top Robot
The UART, or Universal Asynchronous Receiver / Transmitter, is a feature of your microcontroller useful for communicating serial data (text, numbers, etc. ) to your PC. The device changes incoming parallel information (within the microcontroller/PC) to serial data which can be sent on a communication line. Adding UART functionality is extremely use
Robot Tutorials power regulation
The most important schematic to know, one that is almost always required for every robot whether you`re a beginner or advanced, is a circuit to control your robots` power source. You cannot just hook up a battery directly to everything and expect it to work. Instead, there are three things that your power regulation circuit must do - regulate at a
Robot Tutorials current sensor
Current sensing is as it says - sensing the amount of current in use by a particular circuit or device. If you want to know the amount of power being used for any robot component, current sensing is the way to go. Current sensing is not a typical application in robotics. Most robots would never need a current sensing ability. Current sensing is a
Robot Train Cruise Control
Stepper Motor Circuits
Remote Control Circuits
Direction Finder Circuits
Power Control Circuits
Motor Control 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...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial