I had tried to use PWM at first but I couldn't get the desired result, not sure why, but now it works... a little. The code has been updated

It allows me to have smoother acceleration and braking so the mushroom doesn't always topple over, but I'm still not happy with the result, I definitively have to redo this from scratch. I will also add a small buzzer to play the SuperMario tune but I don't have the room with the current design.

The project is shelved until I find the time to learn how to use a 3D printer and improve the design...