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
Digital Voice Recorder/Playback (UM5100)
This Circuit is based on the UM5100 which can record speech into a digital memory and then play it back. The device is designed to be used directly with static RAM's up to 256K bits, or with EPROM 's or ROM's for playback only. High quality voice reproduction is possible and note that it is not a "computer voice", it is the original speaker's...
Real-time speech recognition system application circuit in family care robot
Circuit diagram in the research and design features, are applied on the mobile robot. Therefore the study design systems to take into account small size, low power, easy to mov
Lego Double Rotation Sensor
An opto-interrupter made with Lego beams, regular parts, a 6 hole pulley wheel and an axle.
Control 32 DAC channels via a parallel port
The circuit in Figure 1 controls 32 voltage-output channels from the parallel port of a PC. The circuit comprises eight DAC7615 quad voltage-output, serial-data programmable, 12-bit DACs. The controlling PC individually programs each of the 32 DAC channels, and all DAC outputs simultaneously update. The parallel port's eight data-output lines...
AVR Robot Board
The Atmel AVR series are very good microcontrollers with quite a rich instruction set, rich enough that lots of folks have good compilers for them so we don`t have to learn their assembler. A very rich compiler available is the BASCOM/AVR compiler from MCS Electronics. I`ve used this compiler for prototyping the software on my 90S2313 robot...
The LDR`s were hand-picked. Got two packages of them from Radio Shack, looking for at least two pairs of similar parts. Then added wire-wrap pin sockets, to the circuit, so that the LDR`s could be plugged in. Currently, the 0.33UF cap is not being used on my B-Head`s. I made a long J-hook from "Jumbo Paper Clips", attached it to the motor shaft,...
Code provides adjustable differential drive for robots
Intelligently modifying the motor-drive commands to a robot can give you control finesse during competitions. Moving a joystick hard right, for example, might have different effects, depending on the robot`s speed and direction. Software running on an inexpensive microcontroller (in this case, an NEC (www.nec.com) PD78F9814) manages this control...
DC Motor-Driver H-Bridge Circuit
A very popular circuit for driving DC motors (ordinary or gearhead) is called an H-bridge. It`s called that because it looks like the capital letter `H` on classic schematics. The great ability of an H-bridge circuit is that the motor can be driven forward or backward at any speed, optionally using a completely independent power source.
Dual dc-motor-speed controllers navigate robots
Mobile robots need simple and lightweight dc-motor-speed-control hardware that can work with low-power batteries. Flip-flop type navigation systems allow only one motor to operate at a time while the other motor remains off. Navigation direction changes alternatively even when the robot has to navigate through a straight path. Line-tracker...
Me and a friend are both trying to build a millipede. Because of obvious reasons, the millipede is NOT going to have 1000 feet!!! Instead, it`s going to have 16 pager motors as feet. It will also have 3 MicroMotors to ``bend`` towards light, and a backup sensor.
Handy Cricket Hardware Description
This document presents an overview of the hardware design of the Handy Cricket.
Desktop Line Following Robot
Recently many kind of robot contests have being opened and some interesting reports of the challenge are found on the web. The Line Following is a kind of the robot contests to vie running speed on the line. I build a tiny line following robot which can run on the desk, moving the key board aside will do. It is for only a personal toy reduced...
Magnetic proximity sensors Circuit
Here is an interesting circuit for a magnetic proximity switch which can be used in various applications. The magnetic proximity switch circuit, in principle, consists of a reed switch at its heart. When a magnet is brought in the vicinity of the sensor (reed switch), it operates and controls the rest of the switching circuit. In place of the...
Trimming the Internal Clock Generator on the 68HC908KX8 Microcontroller
One of the nicest features of the 8-bit KX8 microcontroller (manufactured by Freescale Semiconductor) is that it includes an internal clock generator (ICG). This allows the chip to run without the trouble and expense of an external crystal or canned oscillator.
Bugdozer is an autonomous mini-Sumo robot. Her main board consists of a MC68HC908GP32 microcontroller along with input/output support chips, a voltage regulator, a crystal oscillator, and the usual assortment of resistors, capacitors, and switches. All chips are socket mounted. I`m not experienced at soldering, so soldering the sockets avoided...
The microcontroller is able to make about 7000 complete line-following decisions per second, which is almost 7 decisions per millimeter when the robot is going full speed. By upping the clock, unrolling loops, and removing my wireless debugging and extraneous code, I could increase the number of decisions per second.
RF Modem Robotics Project
RF is just way too cool not to use in your designs. But if you`re a newbie like me it is difficult to successfully build solid RF transmitters and receivers. When I started out I didn`t realize that the larger breadboard I was working off of was causing a lot of the signal deviance because the metal traces on the breadboard worked like small...
Inertial-navigation system uses silicon sensors
A strap-down inertial-navigation system uses silicon sensors to measure displacement without entailing the bulk and expense of moving parts or GPS receivers. For example, a three-axis accelerometer and three angular-rate sensors can determine the position and velocity of a vehicle such as a robot or radio-controlled aircraft.
Dual 8-bit ADCs provide pseudo high resolution
By using two 8-bit ADC channels for the same signal, the technique in Figure 1 can accommodate both conditions. One channel, which the controller uses for fast motion, reads the input directly and adds four 0 LSBs for a 12-bit result. The second channel reads the signal amplified by 16 with four 0 MSBs. The amplification gives this channel the...
Ultrasonic range finder
An ultrasonic, or sonar, range finder is a common sensor in robotic systems and industrial environments. Even home and automotive uses are possible. A novel sensor design consists of a WC, a few peripheral components, and a pair of ultrasonic transducers (Figure 1). The range-finder module consists of a WC, a transmitter, a receiver, a...
ALPHANUMERIC LED DISPLAY PROJECT
A tiny sandwich flag connected perpendicular to the motor spindle aids observation of how long it takes to complete one full rotation. This worked initially, as each burst from the capacitor barely moved the flag 1/4 of a rotation. As the circuit variations became more efficient and powerful (the capacitors values became larger), a single burst...
Infrared Detection with 74HC04
The two basic parts for working with IR are the emitter and the detector. The emitter is typically an LED that emits near-infrared light. A typical wavelength is 880nm, which is just beyond the human eyes ability to see. Many suppliers, new and surplus, can provide you with sources of LED emitters. A typical IR detection system will use two...
Audio Detector with LM324N
Here is one that uses a single IC (LM324 quad op amp) and a handful of parts. This circuit is for detecting one of those 3.6khz
Laser Range Finding for robots
The author's articles of months past focus on the application of 32-bit high-powered processors to amateur robotics and more recently applying CPLD technologies to the same. Continuing on this high-tech trend, this article will cover the concepts and implementation of a Real-time Laser Range Finder based on CPLD Processing of NTSC Video for use...
Well the most common use is in a solaroller which is a small wheeled car that charges up and then moves in a quick burst of speed. Since you can only use motors and coils with this circuit robots built with this circuit are mainly mechanical such as my artistic butterflies. One other common use is a little thing called a symet which can roam...
Dual Channel Servo Pulse to H-Bridge Interface
The interface uses a PIC16F876 microcontroller and not much else. It performs channel mixing, current limiting, and noise rejection. Push the stick forward, both motors move forward, move the stick to the left and the robot moves left. It makes the robot very driveable. You can use a wheel transmitter meant for cars to control it, in other...
Stepper Motor Controller
I found this circuit in my files. I don`t know where it came from, but it looks like I photocopied it from somewhere years ago. I have been told that it came from "The Robot Builder`s Bonanza", by Gordan McComb. Anyway, I thought that it should be fairly useful, so I decided to post it here. The circuit is very simple and inexpensive. This is...
Switching regulator drives robot motor
The circuit in Figure 1 shows an example of how you can use an integrated switching regulator (ISR) to efficiently vary the speed of a permanent-magnet dc motor. In this application, the rotating head of a robot senses the presence of an oncoming object (perhaps a human). If the robot senses an object, it slows the rotation of its head to...
The purpose of a motor speed controller is to take a signal representing the demanded speed, and to drive a motor at that speed. The controller may or may not actually measure the speed of the motor. If it does, it is called a Feedback Speed Controller or Closed Loop Speed Controller, if not it is called an Open Loop Speed Controller. Feedback...
Binary to Decimal Converter Circuit
The project is designed as a learning toy with a reward for determining the correct answer (see Figure 1). The object is to represent a random number, from 1 to 255, in binary form by using eight LEDs. The user enters the decimal form of the number using a keypad. The users guess is displayed on an LCD as the guess is entered. Once the guess is...
Computer Serial Port interface
Here is an inexpensive way to get slow-moving analog data directly into a spreadsheet on your computer! A simple circuit connects to a serial port and a short Qbasic program gathers and saves 12 bit data to a file. A spreadsheet automatically retrieves the file and displays the data in real time. Once the data is in the spreadsheet, the full...
Church bell Controller with ATmega32
This circuit is a church bell controller. Basic component is an ATmega32 microcontroller. At the circuit 1 24LC32 eeprom memories is being used. As control I created a menu who will be appeared on 4x20 LCD (Liquid Crystal Display). The menu browsing can be done by 6 buttons at the face of the circuit's box (Menu, Up, Down, Enter, Start, Stop)....
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...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity