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Crossed from: Inside Circuits | Clicks: 6701 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 4
Crystal display (LCD) tester
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Liquid crystal displays are currently available in several versions and various sizes. The wide variety of features, has resulted in there a little chaos in the provision of the pin. So that even when, after much effort, we can find a screen that fits our needs, we are rather difficult to use it. And because most likely we can not find technical manuals to describe all that remains is for us to try to locate the pins by making successive trials. For this work the circuit described below is particularly useful and convenient.
An LCD consists of two thin sheets of glass are few among them. ..
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Crossed from: Thermometer Circuits | Clicks: 35 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Digital Thermometer
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A device designed for measuring time and temperature used in chemistry laboratory. The circuit employs a 89C4051, 20-pin CMOS Microcontroller with built-in 4kB code memory. Temperature was measured by LM35D, National Semiconductor Temperature sensor producing 10mV/°C. The CA3162, 3-digit DVM converts dc output provided by LM35D and sends BCD output to port1 (P1.0-P1.3). The program resided in code memory of 89C4051 was written in ‘C’ language, thermo.c. The program read BCD output from the A/D converter, performs digital filtering,10-point moving average, and sends the output reading to a 16x1 line LCD display. A 10ms cputick was used as a timebase producing 1 s for time counting. The LCD displays time in 1 s and temperature in 0.1°C resolutions...
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| Clicks: 10768 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
LCD to USB interface
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LCD2USB is a open source/open hardware project. The goal of LCD2USB is to connect HD44780 based text LCD displays to various PCs via USB. LCD2USB was meant to be cheap and to be made of easily available parts. It is therefore based on the Atmel AVR Mega8 CPU and does not require any difficult to obtain parts like separate USB controllers and the like. The total cost (without display and pcb) are about 5 to 10 Euros. LCD2USB currently comes with a simple demo application that works under Linux, MacOS X and Windows...
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Crossed from: Voltmeters | Clicks: 1357 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Digital Voltmeter with ICL7129ACPL A/D converter
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This 4 1/2-digit DVM circuit is built around a Maxim ICL7129ACPL A/D converter and LCD driver. An ICL8069 CCZR 1.2-V band-gap reference diode is used for a voltage reference. S2a-b-c select one of four ranges up to 200 V (maximum). The meter also has a piezoelectric buzzer for continuity testing. S3 selects either DVM or continuity. Crystal 1 can be changed to 100 kHz if maximum rejection of 50 Hz is desired. The crystal normally provides 120 kHz for best 60-Hz rejection. This is caused by the dual-slope conversion technique used in IC1...
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Crossed from: Microcontroller Circuit | Clicks: 13575 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
church bell with timer and LCD
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This circuit is a church bell controller. Basic component is an ATmega32 microcontroller. At the circuit 2 24LC32 eeprom memories is being used, the 1st for internal standard melodies and the 2nd one is for user's compositions. This feature will be provided in the future. 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). The all firmware binds about 19Kbytes flash memory and can be increased by adding new features-functions. This program has been writen in C in CVAVR compiler. The idea of this circuit is being given by a friend of mine who has an foundry and he is building bells. I have made the PCB by my self.
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Crossed from: Meters | Clicks: 15118 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
AVR LCD Microcontrolled Oscilloscope
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A few months ago as I was surfing on the net, I saw an oscilloscope based on PIC18F2550 microcontroller and a KS0108 controller based graphical LCD. That was Steven Cholewiak's web site. I had never seen before so amazing microcontroller-only oscilloscope. That was realy impressive circuit, so I decided to design something like that but in C language instead of assembly that I was using all those years. The best solution for me was the WinAVR as it bases on open source AVR-GNU compiler and it works perfect with AVR studio 4. The graphics library that I used, is made by me specific for this project. It's not for general use. If you want to include it to your codes, you have to convet it as you need to. ..
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Crossed from: Various Circuits | Clicks: 5213 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
LCD Car Accelerometer
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The circuit is drawn for measurement of acceleration from 1000 mg until + 1000 mg. It can be placed in kantra'n the car and be supplied from the sheath of electric lighter. The circuit includes one indicative LED and a screen LCD. The measurement of acceleration becomes with the use of IC from Analog Devices, the ADXL202. The particular element contains 2 autonomous vertical between them sensors, for the measurement in two axes. For the particular application becomes use of only it's one. Acceleration meter measures dynamic or static acceleration from 2g until 2g (where g is the acceleration of gravity) and when this is equal to zero, exit is a signal PWM, with Duty Cycle 50%. ..
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Crossed from: AVR Microcontroller | Clicks: 7891 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
AVR terminal for serial port
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The LCD display is represented by the connector X1. It has a HD44780 compatible LCD controller and I'm using the 4-bit interface to send data to the LCD controller. The LED's are multiplexed. I've seen the circuit somewhere in the web. It is possible to connect 12 LEDs with only 4 tristate ports with this circuit. You can address the LEDs setting 1 port high, 1 port low and 2 ports to high impedance. I've only used 8 LEDs because of space problemes in the aperture. The blue points on the photo are four push buttons. On the left side I've inserted an infrared remote receiver (TSOP1738) so that it is possible to telecontrol the computer. Additionaly you can see the RS232 interface built with and max232 and the connector X3. Connector X2 is used for incircuit prgramming...
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Crossed from: PIC Microcontroller | Clicks: 7048 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Timer and Interrupt
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There are 4 timers in PIC18 which are timer0 to timer3. Timers are used when precise timing event need to be generated. Timers are usually used in conjunction with interrupt to keep the timing accurate. This guide will show an example of using timer0 to count a timer for every second. The circuit used for this example is the same as the circuit used in the PWM guide. The back light of the LCD will blink on and off every second, while the counter on the LCD will increase until it reaches 199 then reset back to 0. The counting of second is implemented using an interrupt service routine. The guide will be divided in to 2 parts, 1st part dealing with the setting on Timer0 and the second on the interrupt service routine...
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Crossed from: PIC Microcontroller | Clicks: 18338 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
PWM controller with PIC18f2455
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The use of pulse width modulation (PWM) is common for the use of controlling power to a particular electrical device. Motor speed control, LED contrast control, power supplies are some of the example usage of PWM. 18 series PIC always come with a CCP module which is capable of generating PWM. The picture below shows an example of using the capture/compare/pwm (CCP) module to control the LED brightness. PWM duty cycle is set accordingly using the value obtain from the potential meter through the ADC with 5v being the brightness and 0v dimmest for the LED...
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Crossed from: Analog to Digital | Clicks: 960 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
A/D converter 16Bit with LCD and PIC18F2550
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The analog to digital converter (ADC) is a commonly required in most of the projects. Analog voltage measurement can be done using the ADC hardware built in together in a PIC. The picture below show a simple setup for measuring the voltage through the adjustment of the potentiometer. PIC used in this example come with a 10 bit ADC. In the picture the hex value shown is the ADC value acquired from the hardware. After a simple conversion the voltage can be obtain from this value...
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Crossed from: Thermometer Circuits | Clicks: 7712 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
8 channel LCD Teperature meter ( RS232 - AT90S2313 )
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This is the fully featured, jammed packed temperature readout unit. I can measure temperature from up at 8 DS1820 digital temperature sensors all on the same 1-wire bus. That's right only 3 wires are needed to go to all the temperature sensors, GND, VCC and 1-wire data. All sensors will connect to the same cable! Anyone who has used the DS1820's will know that each DS1820 sensor will have a 48bit serial number that is used to address the sensors. With this unit the microcontroller will search the bus automatically for all present DS1820's and record thier serial numbers in memory. You just connect the sensors and go. You dont have to program in serial numbers of each device...
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Crossed from: Varius Circuits | Clicks: 12473 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Signal Generator 20KHz
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This fucntion gernerator IC is specified to work to 20 MHz. So far, this unit works nicely to 50KHz. Since I seldom need signals higher than that, it has taken up a happy home on my workbench and further development is iffy at best. There are two basic approaches to controlling the frequency in this type of device. One way is to adjust the voltage to the IC manually and then read out the frequency with a counter. The problem here is you need to fiddle around with the control knob and while waiting for the one-per-second updates on the display...
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Crossed from: Remote Control | Clicks: 3211 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Remote IR controller
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This unit provide 2 way IR communications using a numeric keypad and an LCD display. Data is sent and recieved in ASCII with no regard to what the data means to any particular device. The ASCII data still needs some form of encoding. For this I chose 10-pulse coding of 38Khz IR using a nifty 99 cent receiver chip , TSOP4838 The transmitting is done with a straight IR LED with both carrier and coding done in software...
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Crossed from: Clock Circuits | Clicks: 19035 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
LCD digital Clock using PIC16F628
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The reason why I'm using a LCD display is because it allow me to display many characters and it doesn't need to be "refreshed" as 7-segment Led displays. Also, the interface requieres less I/O pins.
For this project I used a 16x1 LCD Display with 4-bits interface...
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