|Original PCB and green gearbox!
The original Wall-E gearbox uses a single motor that allows it to drive forwards or reverse with a turn. Obviously this limited amount of control is insufficient to get through the PiWars challenges, so that needed to be replaced. Along with the gearbox I also removed the existing PCB as it didn't look very reusable, plus the competition requires a Raspberry Pi to be the brains. The speaker, however, I kept as I wanted Wall-E to be able to talk.
Considering ways of making Wall-E move I wanted to keep the weight low to increase stability, so I tried to find a motor that would fit in the side areas of the base. Hunting around I managed to find such a motor, but just couldn't get the axle and shaft to line up. It took quite a bit of time, and various iterations of potential gearboxes, before I finally came to the conclusion it was a lost cause and switched to mounting the motor directly above the axle.
|It fits, but doesn't line up.
|Some of the iterations!
Now that I had proof this was a viable approach I printed out the second gearbox (which ended up requiring some slight modifications, as the base wasn't an exact mirror) and moved on to driving the motors in a more controlled way.