Raspberry Pi Relay

How to use

• Make sure your RPI has IIC installed, see RPI_Hardware IIC section
• Plug the board on RPI 26P connector directly
• Test the board by running following command: for MCP23008, default IIC address is 0x20, you can see the image on RPI page.

sudo i2cdetect -y 1

• Copy code: Make a new py file, paste the following code and chmod it for excute right

nano relay.py
chmod +x relay.py

• If the demo code can not run properly, change the line value 5,8 to 1,4 at "for x in range(5,8):"
• Relay and relevant LEDs will on and off in turns when running this demo code

• Demo code please find here. you know which folder.

Schematic

• See shematic on the right

Jumpers and Toggle switch

• Left jumper to select VCC on either 5V or 3v3, please keep it at 5V for relay use.
• Right jumper for CD pins of ULN2803, keep it on as default.
• Toggle switch from top to bottom are A2, A1, A0 and NC.