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Computer Interface Circuits
Computer Interface Circuits
Recording circuit of phone conversations using PC
This circuit is used to record telephone conversations on your landline telephone. All you will need is this small circuit and subscription of your PC. There are few times when we forget what we said or told us. So we need recording. Sometime, not many years ago, recording of this kind of conversation was done with a small tape recorder. The...
DAC0832 single - bipolar voltage output interface circuit
DAC0832 is a memory device having two input engrave a D/A converter chip, can be connected directly to the computer bus. Its main properties are as follows: 8-bit resolution; s
DAC0832 interface circuit with the 8-bit CPU
DAC0832 shown in Figure 27-13 cushion in the form of a single-phase circuit connected with 8086CPU. Since DAC0832 internal 8-bit data input must be set between the CPU and D/A
Face Recognition Attendance Machine interface circuit
Face through attendance as the worlds first embedded facial recognition machine, the error rate is less than one hundred thousandth of the rejection rate of less than one perce
FM24C256 interface circuit
FM24C256 as shown 27-54 slave interface circuit I2C bus, the address format shown in Table 27-3. A2, Al, AO is set to low (when extended storage capacity, the need to change A2
The data separator is intended for use with 8" flexible diskettes with IBM 3870 soft sectored format. The circuit delivers data and clock (B) and clock pulses (D). These two signals must be in such a sequence that the negative edge of the clock pulse is at the middle of a data cell. Unseparated data (A) from the floppy unit is shaped with one...
An op amp is used to interface between a fiberoptic system and the MOS SCR to multi-cycle, half-wave control of a load. This receiver has two complementary outputs, one at a quiescent level of about 0.6 V and the second at 3 V. By adding a 4.7 V zener in series with the return bus, the effective VqC becomes 5.3 V and also the 0.6 V output level...
This circuit draws only 4 mA from a 5-V supply while driving a standard RS-232C receiver. The system clock drives a de-de converter that produces -3.4 V. The frequency can range from 0.5 to 8 MHz, but a range of 0.5 to 1 MHz will minimize power dissipation. The circuit output withstands direct shorts to ground or to either of the supplies (...
When driving MOSPOWER in a totem-pole output configuration, it is necessary to have the gate voltage 10 to 15 V positive with respect to the source in order to handle load currents near the MOSPOWER maximum ratings. The D169 lends itself to bootstrapping because of its high-voltage ratings. In the circuit shown, the voltage on the 2000-pF...
The circuit illustrates a method of interfacing a HEDS-1000 emitter-detector pair with a HA-5144 for use as a bar-code scanner circuit. The HA-5144 is used as an amplifier system which converts the bar and space widths of the printed bar code into a pulse-width modulated digital signal. Amplifier A1 is used to amplify the current output of...
I/O Line Protectors
A 5.1-V zener diode clamps positive-going transients, and a Schottky rectifier clamps negative-going transients. Th
Versatile One-Shot Cpu Interface
Process-control applications often require a monostable multivibrator (one-shot) with a pulse width that c
Keyboard Matrix Interface
Keyboards can be slotted into two categories, at least as far as the manner that the switches are connected is co
Microcomputer-To-Triac Interface Circuit
A microcomputer-to-triac interface uses a phototriac optoisolator to Jet safety-isolated logic signals directly control high-power loads. Depending on the input waveforms and the load, this circuit can be used in either an on/off switch or a proportional phase control.
Mp pulse width control
Differential multiplexers are generally used in process control applications to eliminate errors due to common mode signals. In this circuit however, advantage is taken of the dual multiplexing capability of the switch. This is achieved by using the multiplexer to select pairs of RC networks to control the pulse width of the multivibrator.
Fast data aquisition 2
a low cost, high-speed monolithic analog multiplexer. The system works as follows: Selects a channel and initiates a conversion at G = 1 and then looks at the MSB of the conversion result. If the MSB = 1, the ?? will store the value. If the MSB = 0, the ?? will select G = 2. The ?? will repeat the cycle of gain incrementing, comparison, and...
High speed paper tape reader
When computer peripheral equipment is interfaced, it is convenient to work with logic signal levels. With a nominal 4 V at the output dropping to - 0.6 V on illumination, this circuit reflects the requirements of a high-speed, paper tape optical reader system. The circuit operates at rates of up to 1000 bits per second. It will also operate at...
Data acquisition system
Charge redistribution to achieve A/D conversion. In typical applications, as a ratiometric conversion system for a microprocessor, V^p, will be connected to ground and VREF+ will be connected to Vcc.
Fast data aquisition 1
This diagram shows a high speed data acquisition system with 8 differential inputs and 12-bit resolution using the AM-543. If the control logic is timed so that the Sample-Hold-ADC section is converting one analog value while the mux-amplifier section is allowed to settle to the next input value, throughout rates greater than 156 KHz can be...
Host computer automatic temperature control circuit
Computer when you run large-scale software or games machine in the heat will increase the temperature inside the machine so that, especially in the hot summer when more obvious.
8-bit parallel input serial output interface circuit
8 parallel input/serial output interface circuit as follows:
Based on AT89C52 minimum system interface circuit
American Atmel AT89C52 is produced by low-voltage, high-performance CMOS 8-bit microcontroller chip contains 8KB of rewritable program memory and 256B of random access data mem
DK04 monitoring module with the computer communications interface circuits
As shown in FIG, D187 is a universal asynchronous receiver transmitter (UART), its RX/TX signal received optocoupler N21, the N22 and N29, so put the RS-485 communication inter
Computerize Your Room/House
So you`ve read about my Computerized Room or have seen those nifty home automation products advertised in the back of electronics magazines? Or perhaps someone you know has done something similar. At any rate, you have decided to try it yourself. The first thing I will say, however is that it is not cheap.
Pic-Plot : a GPIB to RS-232 converter
This adaptor will capture plots or prints of your GPIB instrument to your PC through the serial port. It fills the need of anybody who has a test instrument with the GPIB port and likes to get the screen dump on his PC without any GPIB card. Project based on a PIC16F628A microcontroller.
7 segment rolling display using PC
It is very interesting and convenient to be able to control everything while sitting at your PC terminal. Here, a simple hardware circuit and software is used to interface a 7-segment based rolling display. The printer port of a PC provides a set of points with some acting as input lines and some others as output lines. Some lines are open...
Yet Another ICOM CI-V Interface
This page describes my home-built ICOM CI-V interface. In order to connect most all ICOM radios to a computer, an additional interface is required. The interface bridges the gap between the RS-232 electrical levels used by the computer serial port, and the open collector shared bus used by the ICOM radios. The interface, therefore, is not much...
Microprocessor RS-232 Reset
This circuit allows a remote microprocessor to be reset by a controlling host over a remote RS-232 or similar protocol serial line. With the use of a program loader on the remote host, a program may be downloaded and run. This allows a target processor to run different code in RAM, thus getting rid of the need to burn multiple EPROMs. The...
MIDI Controller Footpedal
Here`s a simple project that sends continuous or switch controller MIDI messages that correspond to the position of a potentiometer. Given a few parts and a cannibalized volume or wah-wah pedal, you can build this MIDI controller pedal and have the ultimate source of controller data in the Universe. This pedal is especially useful in live...
MIDI Drum Machine Project
The MIDI Drum Machine began in the Fall of 1991 as a project for a microprocessor system design course, shortly after I wrote PAULMON1, the 8051 monitor/debugger. A friend, Rod Seely, both a musician and electronics hobbiest suggested I design something using the Musical Instrument Device Interface, MIDI, that would be COOL and would work...
18-bit ADC uses PC`s serial port
A PC usually requires a plug-in ADC card to process analog signals. However, with the circuitry in Figure 1, a PC can communicate with an 18-bit ADC through its serial port. The port provides both positive and negative power supplies as well as control signals. IC1 is an 18-bit MAX132 ADC with a serial interface. It requires three input control...
Control Electrical Appliances Using PC Circuit
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 controlled...
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...
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