PROJECT - CHIPKIT-LED MATRIX - Build Log

ChipKit MAX32 - 9x14 LED Matrix

This project started a few weeks back when one of my Arduino colleagues brought the LOL Sheild to my attention.  (A write up for the LOL Shield can be found on it's designer's page: jimmieprodgers.com ) This is a very interesting little LED circuit that uses a concept called Charlieplexing. Charlieplexing in a nut shell is a way to multiplex many LEDs with as few digital lines as possible.

There wasn't a shield for the MAX32, so I designed one based on the Jimmie Rodgers LOL shield.  The shield is an array of red LEDs in a 9 x 14 "pixel" array.  I have seen a number of cool projects on the web that use this shield, one of which was a Pong Game. Some other uses could be, scrolling text, simple animations, or a graphical display.

My design is in the public domain.  For this design I have tried to follow the Open Source Hardware protocols outlined by OSHWA (Open Source Hardware Association).  (http://www.oshwa.org/) (http://freedomdefined.org/OSHW)

PROJECT FILES:

For the LED Matrix circuit you will find all the project files below.

ChipKIT Max32 - LED Matrix Shield Files

IMPORTANT CORRECTION:  It seems in a fit of some sort of dyslexia I made a mistake on the Shield PCB.  At LED position 9B  I seem to have placed the LED81 instead of LED18.  I have corrected all the documents to reflect this change.  Please be sure your PCB is REV2 if you had downloaded my files.  Sorry about that.

Hardware:

The ChipKit MAX32 is available here!

So, after using the Arduino LOL Shield as a referance, I layed out a PCB and begun milling.  This board is a little more complicated than most of my designs, so I had to through hole plate.

Once plated through, I strapped the board(s) back on the LPKF machine and began cutting.

Once milled out, I did the usual chemical tinning and begun the ordeal of soldering. I begun with the 0 Ohm resistors... and yes I actually used 0 Ohm resistors because they were there really.  Wire works just as well.

Next I soldered the headers.  But, this was a mistake.  I was waiting for my order of LEDs to come from eBay and I got impatient.  The LEDs really should have gone on next because they are shorter than the headers.  It was a royal pain soldering the LEDs last.  

Bring on the LEDs:

An then.... tragically.... 

I was excited to work with my newly created LED Matrix, I downloaded all the appropriate libraries from jimmieprodgers.com.  I had everything installed and ready to go... I hit the upload button to load my sketch to my ChipKit... and error.... not compatible.  As it turns out the ChipKit handles a few things differently than the Arduino.  Namely the timers and interrupts.  So, unfortunately the LOL Shield Library does not work with the ChipKit.  But I am working on it....