View Full Version : Volt meter

01-04-2006, 03:11 PM
hey guys
i need to make a device which will measure 3 voltages(dc, <15dc) and display they on an LCD, and under certain case flash leds(or buzzer).

I was planning to use 8052 since i know how to use it, what other IC's do i need to measure voltage?



01-04-2006, 07:37 PM
You need A/D converter to measure the voltage. Almost all the microcontrollers have A/D converter. But they can accept maximum of 5volts. So u have to do some sort of linear scale down of voltage u need to measure so that it is always less than 5v. One possibility is use voltage divider circuit using resistors.


01-05-2006, 12:55 PM
Try 89c2051, comes with 1 adc. Look up atmel site for DVM.asm for the complete application.
89C2051 is 20 pin 2k flash eeprom and 64 ram.

01-05-2006, 03:24 PM
what lcd should i use??

01-06-2006, 10:32 AM
With what?
If you mean with tjhe 2051, use 16x2 (16 characrers 2 line alphanumeric LCD display.
Download ASMPROC.EXE from Atmel. Has all files necessary for LCD Display. Dont buy 8x2 LCD. It is expensive/ not readily available. Use a 1x16 or better 2x16 line LCD. Its about 150/- to 200/- anywhere with backlight illumination..

01-06-2006, 10:34 AM
Well..there is no adc in 89c2051!! Maybe its a analog comparator used there....

01-06-2006, 10:47 AM
its all the same jack, he wants just 1 voltage channel. You dont need a bulky ADC+ Bulky Software for this.
My query what for? :: there are 2 application notes, 1 with the inbuilt 'op-amp' as slope det. another using Dallas 1620 digital thermometer. Both the app notes will give you lots to play with.....and learn!
The comparator save a lot of trouble. There are a lot of Adc's to try, but I suggest this to robo_guy: It will give you experience with this very little known controller, hands on with LCD Programming, which i see a lot of students 'struggling' and this same setup can be used for plenty of robotic applications with only 20 pins!!!
Try it out too (u might have,jack) with robo-guy. Thats a very interesting Micro!
The LCD can be used for 100s of useful text/numeric/both applications.
The dallas chip may not be easily available, try Bombay or a substitue.

01-06-2006, 03:06 PM
actually i need three voltage channels, but i guess i can sample 1 at a time, i need to display the voltage on the LCD, it is for my oced PC's PSU.