The GP1A57HRJ00F sensor is mounted on a breakout board with a resistor which has pin headers which allows for easy breadboard attachment. This sensor is composed of an infrared emitter on one upright and a shielded infrared detector on the other. By emitting a beam of infrared light from one upright to the other, the sensor can detect when an object passes between the uprights, breaking the beam. This module comes with both the IR optical interrupter and the breakout board.