Still More Digital Medal

Weirdness.

Having missed all my deadlines for the medal I can now relax and go back to the drawing board to get the stupid thing right. I have breadboarded the entire circuit to see where I went wrong.

I got the same sort of weird errors on the breadboard. That's good from a troubleshooting perspective. When I traced it back I came all the way to the MCU pins. Some of the MCU pins can't hold an Active High under any condition except open. The inputs to the ULN2803A are decently high impedance I think. But some of the MCU pins can do it. Others can.

I may have been mis-handling the MCUs the whole time and destroying outputs at random. That could explain what I've been seeing in all my prototypes. I'm going to swap MCUs tonight and see if the symptoms change.

iHobby Expo

iHobby Expo was pretty cool. Its the largest outreach I've done so far. I learned a lot. The Hobby RC crowd was actually pretty interested in what we were doing. That was a little bit of a surprise. I think we'll get at least a couple new members out of this. Woot!

Disappointment

Pretty bummed tonight. I got the new corrected PCB boards today as well as the components to populate them. The boards went together easy. No more hole size silliness. I knew already to solder the UDN2981 on the bottom of the board.

However, the board doesn't work. A few columns light up. The best thing I can say is that soft power works. I have no idea of what's wrong at this point and the chances of correcting it by meeting time are slim.