Arduino + Ethernet Shield Help

[techhelpbb]

Originally Posted by jwallace15

I have this relay board that I was planning on using to turn things on and off. There are miscellaneous things all over my layout that I'm going to turn on and off with the relay board (blue thing).

I understand how everything will work electrically, I'm worried about the programming.

Make sure that board takes TTL input levels and provides the drive circuitry and bypass diodes for that circuitry to drive the relay coils in those relays.

You do not want to put an inductive load on your Arduino pins directly. Use the pins to drive a transistor or suitable IC to drive those relay coils. The picture does not show any drivers but they might be on the other side of the PCB.

[jwallace15]

The relay board has a VCC and GND pin. The Arduino outputs drive transistors on the board that power the relays.