Module function introduction: TCRT5000 sensor infrared emitting diode continuously emits infrared light, when the emitted infrared light is not reflected back or reflected back but the intensity is not large enough, the photosensitive transistor has been in the off state, at this time the output of the module is a low level, the indication of the diode has been in a state of quenching; the detected object appears in the detection range, the infrared light is reflected back and strong enough, the photosensitive transistor saturated, at this time the module's output is low level. transistor is saturated, then the output of the module is high level, the indicator diode is lit. Wiring: 1, VCC: connected to the positive terminal of the power supply (3-5V); 2, GND: connected to the negative terminal of the power supply; 3, DO: TTL switching signal output; 4, AO: analogue signal output (different distances to output different voltages, this pin can be left unconnected)