[Alan Anderson]

The TechnoKats' 2014 robot has three completely independent sensors on its giant flingapult to detect "end of travel", plus a software-enforced time limit on how long it can be powered forward. There's an optical sensor that gets a reflection from the carriage as it goes by, a physical limit switch adjacent to the padded hard stop, and a gear tooth sensor to count distance from the home position. Any two of them can fail, and the flinger arm will still stop before trying to break something.

On previous years' robots, there have sometimes been single sensors that can cause either loss of control or self-destructive behavior if they get disconnected. We typically tried to detect such malfunctions and disable the function in software, but without redundant sensors that's not easy.