So I got my lamp matrix PCB design manufactured from Dirt Cheap Boards:
After some messing around with the programming, it actually seemed to work:
I couldn't really get the light bright enough when they were strobing as fast as they could. But then I noticed some oddities. My TIP107's were heating up a lot. Still not exactly sure why. Then this happened:
Also notice the slight modification I had to make to that ULN2803 chip - had to bend the com leg out. Poor design on my part. You may not have realised yet, but I don't actually know what i'm doing. A lot of trial and error goes into this.
So trying to pump 5+ amps through a tiny little trace like that turns out not to be such a good idea. I needed to re-engineer. Since i didn't want to wait for new boards to be manufactured and didn't want to have to re-solder all those components.