Any way to find out RPM?

The DiddyBorg V2 kit does not have the capability to measure its speed out of the box, but there are things you can do:

1. Make a guess based on the current motor power and battery voltage reading. This requires some experimenting to determine what the actual speeds are.
2. Use the camera to try and determine movement. This can work well, but it requires a fair bit of understanding of image processing.
3. Fit some kind of encoder so you can measure the movement of the wheels. This has the advantage of being able to get an accurate reading of both speed and distance moved.

For the third option il diavolo came up with the crafty solution of using old mouse scroll wheels: My DiddyBorg pictures.