The final design made use of a PIR Motion Sensor. The sensor is powered to 5V, grounded, and connected to digital input pin 2 on the Arduino board. The motion sensor has two potentiometers on its side, one which controlled the sensitivity and another which controlled the delay between detection signals.
The motion detector is able to detect motion from across a room, which caused some issues with staying as still as possible while trying to test and eventually led to the design of cardboard walls for the sensor. The walls act as blinders to narrow the sensor’s detection range and simplifies testing. In a general purpose design, the walls would make sure the sensor only detects motion it’s supposed to.