Comment by VBprogrammer

My favourite crazy bug was during a university course on autonomous robotics. One of the other groups was using a a metal castor at the back of the robot along with 2 driven wheels. After a little while their robot would completely crash and stop responding.

I'd previously encountered a similar issue which was due to the library code we'd been given which opened a new /dev/i2c file for each motor command, eventually exceeding the max file handles and killing the program. So I assumed it was something sensible like that.

Some time later they got all excited and called us over to explain the real reason it was crashing. Their robot would initially work fine for a reasonable period of time. Then when the robot drove over the metallic tape on the floor of the arena it would die. The robot must have been building up a static charge while moving around which would eventually be dissipated when the metal touched the tape.

I wouldn't have believed it had they not setup two tests, one outside the normal arena and one inside. Changing the metal castor for a bit of lego fixed the problem.