PIC driving 2x LED displays directly (16f884)

[takao21203]

this is the displays @ 3 volt, and a graphite cartoon character that I made.

hosted @ photobucket, the image is only 3.9K, if you wish to see it, click the link to photobucket.

By the way I wrote the source in C.
The order of the multiplex can be reprogrammed easily.

[takao21203]

I have added a hex keypad.

There is a tension element to pull together the two PCBs. The gap between the LED displays wires and the new PCB is 2mm!
And it is under great tension.

I use lead solder it's possible to deposit solder tabs.



the keypad: http://i25.photobucket.com/albums/c69/n ... puter2.jpg

http://i25.photobucket.com/albums/c69/n ... yboard.jpg

solder tabs to secure the keypad. It's like one big PCB.

[takao21203]

I have built this circuit into Voltmeter / Amp. Meter (only voltmeter works as for now).

-Supply 3.3 volts using 2576 dc/dc converter IC, from 12v electronic transformer
-Jumper select to 5 volts (modifying 2576 3.3 using a LED)
-7805 chip as voltage reference (12v --> 2.5v)

More than 1K codespace is used by using a few lines code, having two float variables!
And this takes so long to execute, I had to remove it from ISR, or refresh becomes disturbed.

No damage to display, PIC chip = cool (at 3.3V), have this working now for weeks, sometimes 24 hours.
Resistor free...