PiWars 2017: Parts and Experiments


The days to PiWars keep on counting down, and decisions must be made.

Which motors to select, heavy fast, heavy powerful, or the smaller lighter less powerful motors…

Well, testing has suggested that we can use the heavy fast motors, and we are using six of them (which should be enough for the size of robot we are aiming for)

Some parts have arrived, we have the Pi and we have the PWM board.

Experiments with using the PWM board and an Electronic Speed Controller did not go as smoothly as was expected. We did once manage to get the ESC to initialise, but the speed control wasn’t as simple as we’d hoped and as soon as the power was removed it failed to restart.

To simplify things, we have decided to go with an H-Bridge circuit. The only issue here is that most H-Bridges designed for smaller robots have a very low current rating, usually no more than 1 to 2 amps per channel.

We’ve tested our motors and have found that they can pull 1.5 amps each when stalled.
As we have 6 motors, the H-Bridge will need to cope with 9 amps total and nearly 5 amps per channel.

Let’s hope we don’t see smoke!