Relay Control Board - Arduino

How do you get a computer or "Mini Computer" such as an Arduino, to interact with the outside world? Relays is one answer. Computers have  inputs,  keyboard, mouse, cameras, scanners and game controllers as a few examples. Even a few scarce output devices, like a printers and displays. But sometimes 
the Do-It-Yourselfer wants more control over their world. For the purpose of this discussion we're going to use Relays, to accomplish just that.

With a simple relay we can control lights, motors, buzzers and fans. Elsewhere on this website we have a description of a relays turning A/C outlets on and off (Smart Power Strip). (Not for the beginner!)

The purpose of this page is to show the construction of a relay control board which can be controlled by an Arduino, which in turned can be controlled and monitored by a computer. Giving you complete control over the relay. 

    • Remember how you wire the relay, normally open or normally closed will
       determine programming. Unless like our board we have terminals for 
       either option.
Picture 3

Picture 5
Click to download code - PDE - zip

Using a Serial Monitor or CoolTerm, you can monitor the USB port for data, or enter "7" to control the relay.

 Copyrighted 2009 Mac Ramblins