Module description 1 module driven by S8550 triode 2 working voltage of 3.3 V to 5 V 3 sets of fixed bolt hole, convenient installation 4 small board PCB size: 3.3 cm X 1.3 cm 2 Module interface specification (3 wire system) 1 VCC external 3.3 V to 5 V voltage (which can be directly connected to 5 V microcontroller and 3.3 V microcontroller) 2 GND external GND 3 I/O external microcontroller IO port