Putting the robot together, it occurred to me to wonder how to power the motors and the Pi. The original robot ran on 2xAAA batteries – chances of a Raspberry Pi Zero running properly off 3v, plus then powering a motor block? Absolutely, well, zero!
So, I managed to source some AAA Lithium batteries, like these. Each is supposed to provide 3.7v, so that should give me more than enough – and, happily, the Pololu motor board also then supports their voltage regulator which means that I can provide power from the batteries to the motor board and have that power the Pi.
Next problem turned out to be that fact that the original motors in the Tamiya 70097 would very quickly burn out at more than 3v. Thankfully it turns out that Pololu (again!) have clip-in replacements that are rated up to 7v (although I think the preference is 6v), which I very quickly sourced from Proto-Pic and so that’s that quandary settled.
On with the build…