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Charlie plexing/muxing/xing

davedarkodavedarko wrote 07/25/2014 at 08:02 • 2 min read • Like

Yesterday I was chasing duo/bicolor LEDs on ebay.com because I read about blue/red ones on Reactron Integron for Automobile from Kenji Larsen. It never occurred to me that they weren't only red/green ones anymore. Inspired by this I made a 3x5 (15) LED matrix board with charlieplexed pinout in the hope I will be able to make a sometimes purple/red/blue display or colored temperature thingy. This will give me some coding experience since I have to come up with some array magic. I still haven't found out how I can tent the vias in eagle so OSHpark will add the solder stop mask over. The next iteration will probably have 1206 resistors on there and after that I'm going to order the 11*10 matrix I have already designed. This big matrix is perfect for a word clock project but I would need to check my software before. I'm also interested in a clock design as supposed to be seen here: http://hackaday.io/project/1480-Charlieplexed-LED-Clock this would need 9*8 (72) pins (60 for minutes and 12 for the hours) and a good positioning/addressing system.

Awesome links

https://dl.dropboxusercontent.com/u/4345112/www/mrule/charlymuxing/charliemux.html

http://tomscircuits.blogspot.de/2010/10/charlie-cube.html


[UPDATE] Final results

I had to solder two jumper wires to make the connections to fix the somewhat buggy display, but now it's all worked out :) I bought red-blue and red-green BI/Duo LEDs. 

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Discussions

Stefan-Xp wrote 07/28/2014 at 14:33 point
In Eagle you can use DRC --> Tab Masks.
When you change the Limit to a value bigger than the drillsize of your vias the stop mask will not be applied.

Best regards, Gruß Stefan

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davedarko wrote 07/28/2014 at 17:05 point
It's zero and I want them but they are not there...

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Stefan-Xp wrote 07/28/2014 at 19:56 point
"I still haven't found out how I can tent the vias in eagle so OSHpark will add the solder stop mask over. "
I not exactly get it ... i thougt my answer were matching anyhow ;-)
At your image the vias have no stop mask applied. Therefore you could solder to them (they are not painted purple).
We agree the purple is the NOT stop mask (what is left after applying the stopmask?
Do you see the stop mask in eagle?

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davedarko wrote 07/28/2014 at 20:18 point
I will translate this afterwards...

ich mach's mal auf deutsch und übersetze es danach, wenn wir uns verstanden haben :D ich hätte gerne, dass die Vias lila sind, damit ich die nicht aus Versehen mit einer LED zusammen löte. Für mich ist Lötstopmaske gleichbedeutend mit "hier kannste nich loeten weil lack drauf ist" und der Wert der eingetragen ist, ist bei mir 0. Jetzt bekomm ich nen Fehler "Stopmask" wenn ich den DRC laufen lasse und meckert dass ich den Siebdruck auf einem Loetfeld habe.

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Stefan-Xp wrote 07/28/2014 at 20:26 point
I will translate this afterwards...

Ich fand es auch schon etwas verwirrend, dass das tStop heisst, eigentlich wär tSolder oder sowas einleuchtender...
Da wo tStop bzw. bStop ist, kann gelötet werden, falls eine Kupferschicht drunter ist. Also müsstest du bei Limit einen Wert größer als den Bohrdurchmesser deiner Vias wählen, damit die Lötstoppmaske nicht erzeugt wird.
Die Fehler erscheinen erst wenn man die Lötstopmasken anzeigt, die meisten muss man nicht so ernst nehmen.

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davedarko wrote 07/28/2014 at 20:41 point
I wanted to have the purple color over the vias so I don't solder them to the LEDs by accident. My initial thought was that stopmask means I'm stopped by the mask from soldering but it was the other way around. Now I know how to paint on all vias, just put the value for vias in the DRC super high to get everything covered, thanks Stefan!

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Stefan-Xp wrote 07/28/2014 at 20:44 point
You got it right, so i leave my last comment as it is, its the same as you said ;)
*thumb up*
btw: Sorry for the deleted new comments ;)

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davedarko wrote 07/28/2014 at 20:44 point
THANKS Stefan-Xp, I really love this place :) at least for the next boards I know this now, these were ordered immediately after I had them done..

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