Currently for my erasing robot I have it powered by 5V from the USB cable and 6V from a battery pack. This provides enough power for the IR circuit and motors to work together. Next I will be adding a shield to the Arduino.
There are a lot of variables to check. I need to find out what surface my robot can read a line from. So far I have tested paper and black sharpie and that was successful and I have tested white board and black marker. That too was successful but not as reliable. I believe this is due to a bad black marker that didn’t produce rich ink. I will test again with a new marker.
A second variable is weight needed to erase mark off board. I haven’t tested this yet, but my first idea is to have the robot inch forward rotating one wheel at a time to make it “wipe” the mark away instead of just driving over it.
Third variable is driving on the surface of a white board. I have not tested this either, but believe the weight of the robot with rubber bands on the tires will create enough friction to drive on the slippery white board surface.