1. J11 GND, D0, D1,D2,D3,D4,D5,D6,D7 OUTPUT

with D0~ D7 LED

2. This board use GPIO 17,18,27,22,23,24,25,4 control D0 ~D7

GPIO 17,18,27,22 control Relay 1 ~4

3. J28 & J10 (2P Terminal Block) for 5V input for Relay & 2803

4. U5 ULN2803 8 darlington transistor array

5.J15,J17,J25,J24 for disable Relay (remove disable)

6.Step motor connector J12 (5V,D0,D1,D2,D3) J19(5V,D4,D5,D6,D7)

can use Step motor (28BYJ-48 5VDC)