When the module detects an obstacle in front of the signal , the green indicator light on the board level , while low-level continuous output signal OUT port , the module detects the distance 2 ~ 30cm, detection angle 35 degree, the distance can detect potential is adjusted clockwise adjustment potentiometer to detect the distance increases ; counterclockwise to adjust the potentiometer to reduce the detection distance .Active infrared sensors to detect the reflected , and thus the shape of the reflectivity of the target detection range is critical . The minimum detection distance which black , white maximum ; small objects from a small area , a large area from the Grand .The output port OUT sensor module can be directly connected to the microcontroller IO port , you can directly drive a 5V relay ; Connection : VCC-VCC; GND-GND; OUT-IOUsing the comparator LM393, stable ;Can be used for 3-5V DC power supply modules . When the power is turned on, the red power indicator light ;With the screw holes of 3mm , easy fixed installation ;Board size : 3.1x1.5CMEach module shipments comparing the threshold voltage has been adjusted by the potentiometer is good , not exceptional circumstances, do not arbitrarily adjust the potentiometer.Need a 3P Jumper wire to connect(Not Included), If you need it, here is the recommend: http://www.ebay.com/itm/?ru=http%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_from%3DR40%26_sacat%3D0%26_nkw%3D%26_rdc%3D1Pin Definition (3-wire):1. VCC: external 3.3V-5V voltage (can be directly connected to 5v MCU and 3.3v MCU)2. GND: GND External3. OUT: small board digital output interfaces (0 and 1)