What I accomplished this week

All my time this week was spent solving the electrical issue that was causing a short circuit (actually very high resistance, but not infinite) which prevented the circuit from functioning properly.  After spending a few hours with Professor Kevin Ponto analyzing and testing different subsystems of the circuit, we identified that the issue was coming from the H-Bridge section of the circuitry. I checked my design twice and verified that there weren’t any problems with it. This meant that there was an error when populating the board.

What I found was that I mixed up the location of two transistors when populating the board. There was a P-channel where an N-channel was supposed to be and vice verse.   I then removed and swapped the transistors and sure enough, everything is working perfectly now.

See the image below for more details.

Next week’s work

I would like to finish writing and testing the code out on my board.  The reason I have to write new code for this iteration is because I modified the PCB design so that the buttons are now connected to the external interrupts on the microcontroller.  This should help eliminate the delay issues (when the buttons were pressed) I was having with my first iteration.

The transistors in the white boxes were the root of my issues. I had one N-channel and one P-channel in each box, this enabled current to flow directly from power to ground. Q2 and Q3 in the left box should be two P-channel transistors and Q1 and Q4 in the right box should be two N-channel transistors