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8051 / 8052
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Computer Interface Circuits
Computer Interface Circuits
Fax to Modem interface
The circuit can be easily built to a small plastic box with telephone connectors in both ends. The circuit takes about 10-20 mA current, so if the circuit is not in use all the time it is best to use batteries. You can also use small wall transformer to power the circuit. Remeber to take a wall transformer which gives good quality output...
This circuit conditions different signals of frequency below 1 kHz and displays their waveforms on the PC’s screen. The hardware is used to condition the input waveform and convert it to the digital format for interfacing to the PC. The software for acquiring the data into the PC and displaying the same on its screen is written in Turbo C. The...
Simple PC smartcard reader
This simple PC Smartcard reader was shown in Electronics Design magazine February 17, 1997 issue on page 172 in the ideas for design section. The circuit is designed by Jose Carlos Cossio and is based on simple smartcard reader design shown on the same magazine July 8, 1996.
PC Printer Port Controls I-V Curve Tracer
This article describes an I-V curve tracer circuit that uses a computer for display and control. The circuit is controlled via the PC parallel port. Software is provided, written in BASIC, to control the measurement and display the results on the monitor. When connected to the printer port of a PC, the circuit shown in Figure 1 enables you to...
circuits and programs to show how to use PC parallel port output
PC parallel port can be very useful I/O channel for connecting your own circuits to PC. The PC`s parallel port can be used to perform some very amusing hardware interfacing experiments. The port is very easy to use when you first understand some basic tricks. This document tries to show those tricks in easy to understand way.
PC controls light dimmer
Using the simple circuit in Figure 1, you can control the light intensity in your room or work area from your PC. The heart of the circuit is a low-power D/A converter that converts digital words from a computer's parallel port to analog-voltage signals. To isolate the dc low-voltage part of the circuit from the high-voltage part, the circuit...
PC Controlled Voltage or Current Source
This project was begun as a means to charge and cycle NiCad batteries but has become a versatile tool for experiments requiring either a controlled voltage up to +30V and/or a current of +/- 2.5 Amps. If all you want to do is charge and recycle NiCad batteries, then, with hindsight, I`d advise you to buy one of the commerical units available....
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...
Parallel port provides high-resolution temperature sensing
The Dallas Semiconductor (www.dalsemi.com) DS1722 digital thermometer allows measurement resolution as fine as 0.0625°C in digital form and with linear response. The accuracy specification is only 2°C, but you can improve this figure by careful calibration. Moreover, the accuracy spec is unimportant in applications in which you measure only...
Parallel port controls arbitrary-waveform generator
You can use the parallel port of your PC and a few additional components to generate a powerful, easy-to-use arbitrary-waveform generator. By using a Visual Basic program with the circuit in Figure 1, you can generate any waveform (for example, sinusoid, triangle, amplitude- or frequency-modulated, or exponential decay) by simply entering its...
Controlling Devices Through a Computer`s Parallel Port
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...
Control a processor`s power supply in real time
In battery-powered applications in which power management is key, a microprocessor may adjust its core voltage corresponding to an increase or a decrease in clock speed, allowing full processing power when necessary but not wasting excess power when idle. The circuit of Figure 1 shows how an embedded processor can control its own supply voltage...
Single Supply RS232 Interface for Bipolar AD converters
The LT®1180 RS232 transceiver includes a charge pump which produces low ripple supplies with suffi - cient surplus current to drive a CMOS A to D converter and precision voltage reference. The circuit in Figure 1 operates from a single 5V supply, and draws a total quiescent current of only 37mA. These features make the circuit ideal for...
24-bit parallel port interface with 8255
If you are searching for the 8255 datasheet, click here. Another project describing the 8255 interface to PC is here.
PC 8Way Relay Board
This board is designed specifically to control the 5-motor Robot Arm sold by Baycom Technologies. It has no input facilities, but it is less expensive than combining the I/O Board with the Relay sub-Board. If you need lots of relays and no input, this is the way to go.
LCD Display printer cable with HD44780
Connecting a LCD display to your personal computer is an easy job. Displaying data from your PC to a LCD can be proven very exiting, so give it a try and build your own today! In this article we will use a 2 lines x 16 characters LCD display with Hitachi HD44780 onboard controller. You can use any size of LCD like 1x16, 2x40, 4x20 e.t.c but keep...
RS-232 to TTL cable with MAX232
Here is a diagram of the internals of the MAX232A. It shows a double charge pump voltage doubler and a +10v to -10v voltage inverter. The voltages output are used to generate the RS-232 compliant signals. The MAX232A has provisions for two serial ports on the same physical package. Most people only connect one of them. You can get a data sheet...
Casio cable for PC
Clean the surface to be glued components to the printed circuit. Use a sheet of very fine sandpaper to smooth bumps fortunes. First attach the resistors and diodes. Pay attention to the polarity of the diodes! Then glue the two finished watching the first position of the pin. Finally you can glue the two capacitors paying attention to the...
LCD to LPT board
The "LCD2LPT with Lirc" circuit is the compilation of two circuits found on the net on a single board. The first is LCD to LPT interface and the second an IR remote control interface using http://www.lirc.org program. The main circuit for LCD connection to LPT was modified adding a backlight and contrast control using 4 push buttons. Responsible...
A serial cradle
This project is aimed at building a small circuit that fits into a standard USB Visor cradle and that adds RS-232 capabilities. Note that Handspring sells a serial cradle but if you have more time than money, do it yourself and you will have a 2 in 1 cradle !
RS-232 surge protection
The following circuit are provded here to give your idea how the overvoltage protecton circuits really work and how you can easily add some protection to your circuits. To make theose circuit really effective need careful component choosing and good construction. For best performace I recommend using commercial units from realiable data...
PIC to RS232 Interface
The circuit shown will convert logic level voltages to and from RS232 serial voltages levels. For basic serial comms between a Microchip PIC and a PC or other device you generally only need to connect the Gnd, Txd and Rxd lines. This little circuit will work with a supply voltage of 3.3v to 5v making it ideal for interfacing with a PIC
Simple Parallel (Printer) Port Interface
This is the basic interface I used as part of my Computerized Room project. This is the parallel interface only. The 8 bit input card can be found, along with the rest of the project, at Computerize Your Room/House. This interface, as well as the other two interfaces, came from the book "The Robot Builders Bonanza", by Gordan McComb. This...
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...
Wireless Coupler Terminal Interface
The purpose of the terminal interface is to allow my computer to communicate with Minimum Mass Wireless Coupler equipped devices using a terminal emulator program. Consequently, the Base Unit is basically an RS-232 interface and Minimum Mass Wireless Coupler. The Base Unit is the larger enclosure in Photo 1. The RS-232 interface to the...
Serial port Infrared Receiver
This is a general purpose serial port infrared receiver. With the help of appropriate software (see below) you can control different functions of your pc from a distance. For example you can control your home cinema settings (volume, play, pause, stop etc), your winamp etc. It uses for receiver TSOP 1738 (38 KHz) but it worked well with TSOP...
8 Channel software controlled for PC fan
This article is about a software controlled, parallel port-interfacing 8-channel Pulse-Width-Modulated fan controller. I'll admit that the electronic part of it isn't very advanced, but hopefully the idea of "interfacing" might be interesting. My old partner and I were working on an improved version, using an ULN2803A instead of the many...
PC Infrared Receiver
This is the latest version of the Improved Infrared Receiver with Status LED which can control any desktop PC with an ordinary remote control. The project comes along with a small PCB in order to save space. It connects to the serial port as stated in the schematic and uses the freeware Girder (www.girder.nl) software together with Igor?s Plugin...
Cold Atom Control System for PC
We have developed a powerful yet inexpensive and easy to construct experiment control system. The construction of the system together with the control software is described here. All circuits and software are free to download and use for nonprofit. The system was developed for the BEC (Bose-Einstein condensation) experiments in the group of Mark...
8 Channel LPT relay board
Channel Relay Board is a simple and convenient way to interface 8 relays for switching application in your project. Input - 12 VDC @ 336 mA. Output - eight SPDT relay. Relay specification - 5 A @ 230 VAC. Trigger level - 2 ~ 5 VDC. Berg pins for connecting power and trigger voltage. LED on each channel indicates relay status. Power Battery...
Ethernet Controller with PIC18F452
This circuit is an ETHERNET controller I use the PIC18F452 and the mikroC C Compiler. I use also the JAVA SCRIPT information you can get from www.w3school.com I Control 8 outputs throw the WEB and transfer time information also. I use 3 timer and 3 buffers each one has it?s own time Start ? Stop and the outputs will take the buffer BIN value....
Data Transfer interface
The DS protocol was designed to provide firmware-based bidirectional host-to-slave inter processor communications for situations in which no hardware solution is available and the host and/or the slave in incapable of tending the interface in real time. The only specialized hardware required is two bidirectional I/O ports on each chip...
USB 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...
Digital Signal Integrity
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