Hacknotts 2015
Hacknotts is a hackathon (24 hour programming and hardware event) hosted by the Computer Science department's student society at the University of Nottingham. In 2015, my team and I, with no real project idea, turned up carrying a budweiser box full of batteries and simple electrical components and breadboards. We also brought a raspberry pi matchbox linux computer and some arduino microcontroller boards of various sizes.
With these components, and inspiration from the success of the (topical) curiosity rover landing, we decided to make a remote control cardboard box which we covered in christmas decorations and attached wheels to. We made an android app (with animated buttons!) to connect to the arduino via bluetooth and use the touchscreen as a d-pad style 4-directional joystick.
The drive circuitry used an H-bridge configuration to drive both rear wheels to go forward/backward and driving one wheel forwards and one backwards simultaneously to turn left and right. The photosensor simply caused the rover to randomly turn left or right when it detected an obstacle. With refinement, it could be made to reverse and try various directions or any other manner of responses to detecting an obstacle (we would probably draw inspiration from a Roomba if we wanted to make it more sophisticated).