1) PCB board size: 23*17*9mm; 2) patch process, LED status display; 3) compact size, sophisticated technology; 4) instructions: use ULN2003 high power Darlington chip to drive stepper motor driver; B, C, A, D LEDs indicate the state of the working four-phase stepper motor; set with the standard interface of stepping motor which can be directly inserted in the use; with diameter 3mm screw hole to make assembly fixing convenient. Interface Description:VCC and GND power input is range from 5 to 24V ;IN1-IN4 corresponding test program 51 microcontroller P0.0-P0.3