Having trouble finding a datasheet

[Fluroblue]

hey guys! How is everyone? Haven't been around for a while! Im pulling apart an old digital clock and trying to find the datasheet for the display and having trouble. UIn other news im going to UOW next year to do Electrical Engineering! So excited! Any advice?

[brad]

Good to hear from you again

Normally a display like that would have all of the Cathodes connected together for each display. I.E. every single cathode for the very top segment are connected to each other, then every cathode for the four bottom segments are connected to each other and so on for the remaining segments.

Then within each of the four seven segment displays, the Anodes are all connected together. So normally you would need:

7 connections to line up with the cathodes
4 connections to line up with the anodes

There are of course other connections for the decimal point dots and the dots inbetween hours / minutes etc...

So to get it to display something on each of the four segments, you have to 'activate' one of the four anodes. Then send some data to the cathodes. one of the four displays will light up with the information because that is the only one that has its anode activated. You would then turn off that anode, activate the next anode in sequence, and send new data to the cathodes to be displayed. You have to keep going once display at a time ensuring that you keep the speed up to such a level that the human eye can't see that you are actually cycling through the displays.

I don't have a data sheet for you but I would find it out by trial and error. get a 9v battery and a resistor and test between different pins to figure out what pins light up what segments etc...

That's how I got all of my LED matrix displays to work!

[Fluroblue]

Thanks! Ive been messing around with some shift registers so i want to end up controlling it with them.

[brad]

Be sure to post back and let us know how you get on with this project

[brad]

In fact, here's a page that I think will help you on your way

http://learn.parallax.com/4-digit-7-seg ... duino-demo

[Fluroblue]

sick thanks! I still need to get my soldering iron from the garage