[Monochron]

We used an Arduino Nano to run a light sensor for position sensing. We mounted an LED on our ball lifting mechanism and the light sensor on a piece of aluminum such that when the LED was in front of the sensor the lifting mechanism was in our "shoot" position.

In order to filter out outside light we pulsed the LED every couple milliseconds and used the light sensor to give us the delta between the two readings. If the delta was large then the LED must be present.