Edison’s Infrared Light Sensor

In addition to Edison’s light sensors that you learned about in the previous activity, Edison also has an infrared light sensor or IR sensor. This sensor allows Edison to give out and detect infrared light. The sensor is made up of three parts total. There are two infrared LEDs (one on the right and one on the left) plus an infrared receiver in the middle. See if you can find these on your Edison.

Source: Adapted from [1 p. 158]

Edison uses its IR sensor to detect obstacles. Edison does this by emitting infrared light from the two infrared LEDs. If that infrared hits an obstacle, like a wall, the light is reflected back towards Edison and its infrared receiver detects the reflected light. This tells Edison that there is an obstacle. Depending on where the obstacle is, infrared light will bounce back from the left LED, the right LED or both. The reflected light tells the robot where the obstacle is located. 

Source: Adapted from [1 p. 158]