This is a very easy and fun to build project that will allow you to control up to eight external devices through your computer's parallel port. You may for instance control different appliances such as lamps, computers, printers, tv sets, radios, music systems, air conditioners, air fans, garden sprinklers and anything else you can think of, all through your computer.

Stepper motor driver that will allow you to precisely control a unipolar stepper motor through your computer's parallel port. With a stepper motor you can build a lot of interesting gadgets such as robots, elevator, PCB drilling mill, camera panning system, automatic fish feeder, etc. If you have never worked with stepper motors before you will surely have a lot of fun with this project.

High fidelity external USB Soundcard / USB Headphones project that can be built for your PC or Mac. It is based on the latest PCM2706 IC which functions as a high quality, crystal clear 16-BIT Stereo DAC. It is a single chip digital-to-analog converter that offers two D/A output stereo channels, digital S/PDIF output and requires very few external components. PCM2706 includes integrated USB 1.0 & USB 2.0 compliant interface controller and it is conveniently powered directly from USB connection. PCM2706 is a USB plug-and-play device and does not require any driver installation under Windows XP and Mac OSX.

With this project you can show the temperature on you PC. This thermometer plugs on any free serial port. It gives temperature readings accurate to 0.5°C with no calibration.The project consists of the AVR 2313 Project board and the DS1621 Thermometer board and software for the PC.

Each fan turns off when the temperature drops 5 degrees below its turn-on temperature. For example, if the dial is set to 80 degrees, the fan turns on at 80 degrees and turns off at 75 degrees. This prevents the fan from cycling on and off rapidly, which would occur if the fan turned on at 80, started to cool the cabinet, and then immediately turned off at 79.

PC LED Load is a device and software designed to display many shades of colors from green to red on your computer case LED. Colors are controlled completely by software and can be updated in real-time. The PC LED Load circuit board is connected to one of the internal USB ports found on most newer motherboards. The only actual case modification required is in replacing the two (or more) front panel LEDs with tri-color versions. These are then connected to the PC LED Load circuit board.

This project's purpose is to design a fully automated machine for drilling a printed circuit board, (PCB) blank at a minimum cost and with the minimum amount of custom machining. This low cost philosophy is achieved by adapting the existing mechanical assemblies from readily available computer peripherals and electronic measuring instruments. Drill data is transferred to the PCDrill from an Excellon drill file generated by a PCB CAD program running on a personal computer.

A few time ago I decided to create a media center box to replace my DVD player, satellite receiver, VCR and my kid's Play Station 2, to one device. So, I made a core 2 duo processor system that actually replaced with succeed, all my electronic devices. The only thing that was missing was a remote control to switch On/Off my Media Center. After I searched on the net to buy a complete remote control system, I saw that the price was a little bit high (about 90 euros). I checked my stuff to find my old 7-in-one remote control that I had bought 2 years ago and I started to build my own remote control receiver circuit.

RS232 ports of modern laptops are not always complying with the original RS232 standard. If RS232 levels are expected to be +/- 12 volts, most of the time laptops RS232 ports produce in fact +/- 5 volts levels. For most peripherals, this is not an issue and they are responding as expected.

This article shows how to use the PIC16F84 microcontroller with PicBasic to design a quick & effective, serially controlled, I/O-Expander. Using PicBasic makes developing handy single-chip devices like this extremely simple.

There are a few different ways of doing this but basically you have to make the heatsinks NOT live and you have to provide better cooling for the transistors. The heatsinks used in PSUs are generally soldered to the PCB via little metal tabs and current usually flows through them, ie they are live with voltage and act as part of the circuit. What you have to do is cut the tabs which takes the heatsinks out of the circuit and them use wire to replace them in part of the circuit.

This is a very simple design of digital oscilloscope. The original project comes from EP 8/2004. The only difference I've made was adding RS232 to USB converter to use it with my laptop. Schematic can by found here: analogue and digital. There can be seen analogue input section with OPA2350 amplifiers and relays as voltage dividers. ADC is fast television IC, TDA8703. Digital data goes through DS89C420, via USB to PC application showing results. It is harder and harder to find RS232 connector in modern computers. That's why I decided to make this converter. I doubt there is at least one computer without USB.

If you need to add simple data acquisition capabilities to your PC, then look no further than the Analog Interface Unit. The Analog Interface Unit (AIU) is a simple circuit that connects to a PC parallel port, and allows you to sample and output 8-bit analog signals under software control. Here are some of the features : * 8-bit ADC and DAC * Powered from the parallel port * 1Mohm input impedance. * Software selectable +/-1.25V or +/-2.5V input and output ranges.

Simple PC Steering Wheel. Jest to schemat prostej kierownicy do PC. Nie jest to najnowszy model kierownicy z pełnym wyposażeniem i dodatkami typu obsługa wstrząsów, ale proste i tanie urządzenie nie wymagające dużej wiedzy do jej budowy. Naszą kierownicę należy obudować najlepiej w jakąś wytrzymałą i estetyczną obudowę. Potencjometry BRAKE i GAS należy obudować w jakieś pedały (popatrz jak wygląda pedał do regulacji prędkości przy maszynie do szycia). Po poprawnym i dokładnym zmontowaniu kierownica powinna działać bez zarzutów.

This small realization, based on one of the most common IC (MAX232) is designed to create a small and convenient TTL to RS232 and vice versa converter. All you need is 4 caps, one IC and 2 connectors. If you want to add a small regulator on the board (already foreseen on the PCB) you just need to add a 78L05 regulator and a cap.

The UBW board is a small board that contains a Microchip PIC USB-capable microcontroller, headers to bring out all of the PICs signal lines (to a breadboard for example), only costs about $15-$20 to build and is powered from the USB connection. I designed this board to be a simple parallel port replacement tool for Bruce Shapiro for use in his bits-to-bytes-to-bots class. Apologies to all other 'Whacker' projects like EDTP's Packet Whacker for stealing a great name . All tools used to design this project are free, and the design is open to anyone to use for whatever they wish. Please build your own and improve upon it!

The circuit's pretty simple, basicly it's just a voltage regulator. Both the LM317 and the REG1117A (LDO) fit the PCB, maybe there are even more types that I'm aware of that can be used on it. I did add one extra thing: a LED that shows if the connected device is consuming power. To do this I used a shunt resistor and a current converter. I choose 0.2 ohm for the shunt, since it's not hard to come by and should only drop 0.1V @ 500mA. Either an INA168 (current output) or an INA193-198 (INA194 is best in this case) (voltage output) will fit as current converter. The trip point at which the LED should start to burn can easily be adjusted by one resistor (in case of the INA168) or by two (in case of the INA193-198). In the schematic it is set at 100mA using an INA168 using a 950k resistor. The Schmit buffer is a Texas Instruments Little Logic chip (1G17).

USB switch is used to share USB devices such as printers, scanners, hard drivers, etc. between two computers. Just connect the two computers on a network device and say the printer as shared. This method however requires the continued operation of the computer we plugged the printer. Solution to above problem is to give the circuit that we present, and has the potential to be transferred to the printer on whichever computer we want, because the printer is connected to one of two computers, but in construction.

USB to Serial Adapter RS-232 Serial Port to USB The USB to Serial adapter (converter) lets you use a serial PDA, GPS, cell, etc. with a standard USB port. This adapter is the easiest way to add a serial port to your computer. Many PDAs, digital cameras, GPS units, barcode scanners, and other equipment require a serial connection, and many newer computers don't have serial ports.

USB to serial interface is based on the powerful FT232 chip from FTDI. It enables very easy connection of the user's application to the PC via the USB port, without necessity of any deep knowledge about the complicated USB problems. FT232 chip is capable to transfer data at speeds up to 1M Baud in RS232 mode and up to 3M Baud in the RS485 mode. Schematic contains the on-board serial EEPROM (93LC46) for storing the ID data (VID, PID, serial number and description strings).

This connector is found on most Intel-PC's. It's quite easy to feed VGA-monitors with Macintosh-signals (or the other way around: attach a Mac-monitor to an Intel-PC). Most modern VGA-monitors are quite tolerant regarding vertical- and horizontal-sync frequencies.