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
Isolated RS-485 and RS-422
Many RS-485 and RS-422 networks require isolation for safety, noise reduction, or ground loop elimination. A conventional circuit is shown in Figure 1. Unfortunately, optocoupler isolation is slow, complicated, and unreliable. Although RTS does not require the same speed as TXD and RXD, the optocouplers require a Schmitt trigger before the...
RS232 cable modem
First of all you have to build one cable adapter to connect the female 9pins connector of the modem, with female 9pins connector of the base of E-10G HPC. To build the null modem cable you will need: 2 male connectors with 9 pins. 15cm cable with 7 wires. The schematic at the left , its show how to connect the wires. When you finish it, you can...
PC thermometer schematic
This incredibly simple thermometer plugs on any free serial port. Does not make use of any programmable components as microcontrollers. It gives temperature readings accurate to 0.5°C with no calibration. It's cheap, so I've put one on any PC I use. And it is so nice to have the temperature shown on the Windows taskbar, that a million friends...
IR remote control for PC
This simple circuit allows you to record any IR remote control signal on your PC, and then play it back. This is particularly useful if you want to control appliances such as TVs, VCRs, CDs etc. from your computer. The device simply connects to the parallel port of your PC. You can also use this circuit to analyze the waveform from any IR remote...
Stand alone CDROM audio driver
Most of the CDROMS available have an Audio-Out Output to either plug in the headphones or connect it to an amplifier. This circuit enables one to use the CDROM as a stand alone Audio CD player without the computer. This circuit is nothing but a power supply which supplies +5v, +12V and Ground to the CDROM drive and hence can be used without...
Equipment controller with PC
Here is a circuit for using the printer port of a PC, for control application using software and some interface hardware. The interface circuit along with the given software can be used with the printer port of any PC for controlling up to eight equipment . The interface circuit shown in the figure is drawn for only one device, being...
i2c interface to USB interface
The i2c-tiny-usb project is an open source/open hardware project. The goal of i2c-tiny-usb is to provide a cheap generic i2c interface to be attached to the usb. It is meant as a replacement for those simple and cheap printer port to i2c adapters. A USB solution has several advantages incl. the built-in power supply and a more future proof...
Acceleration sensing USB interface
The TiltStick is a small acceleration sensing device in form of a USB stick. It's using a two axis acceleration sensor to measure acceleration (caused e.g. by motion and tilt). The device is emulating a USB joystick and can thus be used in conjunction with any USB equipped host (e.g. a standard PC or the Nokia N8XX family) without any special...
Ethernet board for C64 and SX-64
Once i had my SX-64 repaired i wanted to do something cool with it. I learned about people who added ethernet interfaces to their C64 and since i had some spare ones of the required ethernet chips, i decided to build the net64 cartridge. See the image above for my SX-64 with the net64 cartridge installed. The net64 cartridge is compatible to the...
Wireless Lan for AVR microcontrollers
The page is about equipping an Atmel AVR microcontroller based system with a Prism WLAN interface. This document is intended for people that already have experiences with the AVR microcontrollers and teaches them how to add a cheap but flexible WLAN interface to your AVR projects. At least two other approaches exist to accomplish this. Both of...
AVR Compiler toolchain for MAC
If you want a powerful, free and portable compiler for the AVR you'll end up with gcc. Fortunately, gcc is supporting the AVR cpu for quite some time now and e.g. the WinAVR toolchain for AVR development under windows is based on this compiler. Many people have already ported these compilers to MacOS X incl. the fink project and others....
PC parallel port Null Printer Adapter
This circuit is a simple adapter for PC parallel port to think that there is a printer connected to computer. This adapter is useful for testing printing speed with different software and as a part of your own designs. You can use this circuit to connect your simple circuits to the parallel port. Usually many home-made circuits use parallel port...
Digital Compass for PC
The digital navigation PC board may be configured for a number of navigation functions, see figure 1. It may be made into a simple visual digital compass, or a microcontroller based compass. The microcontroller based compass can be used for mobile robotics or a PC based compass. The sensor used on the PC Board is the 1490 digital compass...
PC Microphone Preamplifier
Soundblaster soundcard series (SB16, SB32, AWE32 and AWE64) have all a microphone input designed to be used with the electret microphones which come with the soundcard package (some packages) or with separate microphone designed to be used with SoundBlaster soundcards (there are separate microphones and some monitors have built-in microphones...
Power from PC's RS-232 circuit
The following circuit is an example how to get power from RS-232 serial port. It gives regulated +5V power for logic circuits and also unregulated positive and negative power supplies for RS-232 transmitting circuit. The circuit gives only few milliampres power output because the power available from serial port is limited (and resistors R1, R2...
RS-232 data buffer
This is a simple serial port buffer circuit I designed for a friend to speed up his SLIP connection in campus computer network "TRINET" of Helsinki University of Technology. The problem in the network was that the RS232 commections from rooms to terminal server were long and made of bad quality wiring. The circuit is a simple buffer which adds...
Overvoltage protection for RS232
RS-232C serial port lines are quite prone to be damaged by overvoltages. The damaged to computer serial ports have become more and more expensive to replace because of higher intergaration: usually you have to buy new motherboard if one serial port in it gets broken. So it is wise to use some extra protection in situations where overvoltages...
4x15Watt 12volt power audio amplifier
While I would have liked a 4 channel chip with about 20 Watt per channel, the local parts store didn't have any yet, so I opted for two TA8215AH stereo chips, selected by their low price in this particular store. The design? Oh well, there isn't much to it. The circuit I used is almost an exact copy of the circuit suggested in the Toshiba data...
PC terminal using a TV
When you use microcontrollers in your designs, sometime you face a problem how to show user required data. Several LEDs, 7 segment display or LCD module can be solution. But if you must show a lot of information simultaneously, it can be difficulty. Large LCD modules are expensive and graphic modules require complicated control. You can solve it...
SmartCard adapter / interface for PC
This smartcard adapter follow exactly the specification ISO 7816. Also, the protocol is the "asynchronous half duplex T=0 protocol" with "active low reset" and "inverse convention" as defined in this standard. The following description may be used in order to connect computers to ISO 7816 compatible chip card systems (e.g. GSM mobile phones or...
LED output from SB Live! Value
Many modern audio recorders is now compatible with digital input S / PDIF (Sony / Philips Digital Interface). Devices like CD Changers, MiniDisc recorders, computer sound cards and the like. working with digital signal just with protocol S / PDIF. Digital connection of two devices, for example. sound card with MiniDisc avoiding D / A converter...
PIC Programmer schematic RS232
In the article you will find a description of the universal PIC programmer, which suggested the involvement of Jens Madsen Dyekjar [ http://www.jdm.homepage.dk/newpic.htm ]. Program allows districts PIC12C5XX, 12C67X, 16C55X, 16C61, 16C62X, 16C71, 16C71X, 16C8X, 16F8X, serial EEPROM 24Cxx. It allows to program the microcontroller directly...
Variable Fan Controller
When the fan seized up in my source and I changed it to a type with much less noise, turned on my computer, the largest source of noise CPU cooler fan. The computer I have a boxed Pentium III processor in slot 1, which is practically dismountable and fan replacement would be difficult. "Boxing" is a type of fan with ball bearings and replacement...
RS232 reciever schematic
This circuit was designed to control a 32 channel Christmas light show from the PC serial port. Originally designed with TTL logic, it has been simplified using CMOS circuits to reduce component count. It is a fairly simple, reliable circuit that requires only 4 common CMOS chips (for 8 outputs), an optical isolator, and a few discrete...
Simple RS 232 Level Converter
When you need connect your Microcontroller Project to COM port in PC you need RS 232 converter. There are many chip to solve the problem like MAX232, DS275 etc. But if you need simple and chep for RS 232 converter, i though this circuit will be usefull for you. The design made by Wichit Sirichote. "A circuit diagram shown above was used two small
Db15 Vga Diagram Schematic And Pinout Schematic The Db15 Vga
MotherboardCircuit Free Download
rs232 to rs485 circuit
The new archetypal of RS485 advocate overcomes the RTS controlled botheration accomplished by our chargeless design. However, to do that requires a microprocessor, so there is a greater complication to the design. We advertise this unit, although currently we are attached our sales to barter who can pay by coffer alteration which in absolutene
High quality pc audio amplifier
High quality audio amplifier for computer circuit diagram. The electrical circuit of the amplifier is shown in Fig. 1. For its production is chosen in a typical IC TA8205AN inclusion. Usually it is applied to a Hi-Fi class due to low harmonic distortion. Suitable as a similar but more powerful: TA8210AN TA8215AN and (wiring diagram in this case do
Serial COM port using ATmega8
Many times, I have written code for UART communication and when it came to testing, my laptop does not have a serial port. I bought a USB to serial port converter but it didnt worked. I felt frustated and finally thought of buying a Serial to Com port module in an electronics hobby store. After seeing that I got the idea of making one myself. I ha
Radio Control a two wheel robot from your PC
Well, it took some time and a few failed attempt, but here it is. A neat project that lets you control two wheels or tracks from your PC serial port with no wires attached. I have it working at 2400 baud and that is about as fast as I can think. We assume you have a PC, so what else do you need First a Basic Stamp. I am using the Stamp I, but a B
Laptop Notebook Schematic
Laptop Schematic Circuit Diagram for Laptop Repair, Laptop Bios Password Remove.
USB Interface Circuits
Computer Interface 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