DVM ideas

Hi,
I want to try and use an avr to make a simple DVM, using 7-seg LED displays.
I wont be using an arduino, but a standalone '328 programmed with the arduino dialect.
The input voltage will be around 0.5V maximum, so the A/D converter will yield a decimal
result of 100, stored, presumably, in a long integer.
For reasons which need not detain us, I will multiply that figure by a fudge factor, so that the maximum
reading I get will be 2500. Now, how to get this to display as 2500 on four 7-seg displays?

I was guessing that you could ( somehow ) isolate each digit in its own integer and display them
sequentially on the display, but the gap between that and an end result is very wide indeed.

Yes, I have Googled: everybody uses LCDs

Can anybody help?
Regards
bruce

Try googling
seven segment multiplexing arduino
there are lots of schematics and code.

This is one:-
http://learn.parallax.com/4-digit-7-segment-led-display-arduino-demo

Sparkfun has a bunch of serially enabled 7 segment displays that will make your job a lot easier:

analogRead returns an int.
100 x 25 = 2500, still an int.
use the modulo command to split the number up into its digits

poriet:
Hi,
I want to try and use an avr to make a simple DVM, using 7-seg LED displays.
I wont be using an arduino, but a standalone '328 programmed with the arduino dialect.

Sparkfun have something very similar to what you describe.

They publish the circuit and the sketch, so that should give you some ideas.