• On-board LM393 voltage comparator chip and infrared sensing probe. • Support 5V/3.3V voltage input. • On-board signal output indication, output effective signal is high level, and the same time the indicator light up, output signal can directly connect with microcontroller IO. • Signal detection sensitivity can be adjusted. • Reserved a line voltage compare circuit (P3 is leaded out). PCB size: 30(mm) x15(mm).