An Infrared emitter, or IR emitter, is a source of light energy in the infrared spectrum. The infrared tracking sensor module uses TCRT5000 infrared reflection sensor whose infrared emitting diodes are constantly emitting infrared rays. When an object is in detecting range, infrared rays will be reflected back with high intensity, the module outputs high level and indicating diode is on. When the infrared ray emitted is not reflected back or intensity is not high enough, the infrared receiving tube is in the off state and module outputs low level, while indicating diode is off.