IR alternatives

I’m not sure about this, but I think that under signaling devices in the rules, it says that you can use sonic, IR, or visible light. If this is allowed, how would you set up a system that uses sound or visible light?

The short version is “put a sensor on the robot that can detect “_____” (IR/Light/Sound) and then program it so it responds to four different inputs”.

The longer version is left as an exercise for the astute student.