Safety Stoplight: The Easy, Arduino-powered, voltage warning light

This was a side project I completed during my time as Summer Undergraduate Laboratory Intern at the National Renewable Energy Lab. I highly recommend the program. (I did much cooler things than this, but those will be papers not Instructables :)

We worked with some occasionally high voltage equipment that required handling from time to time. We built the stoplight as a way of tracking the voltage and staying out of the way when the system was hot.

Perhaps the best  we had was to idea have all three lights flash when there was no signal at all. That way you're not deceived by disconnected cables.

I suppose this project owes big debt of inspiration to mkanoap's network stoplight though this project differs in the simplicity of the components used in the assembly. Thanks to the friendly components of Mouser electronics Arduino Tinker kit, it was built with almost no soldering.

Bill of Materials:
Chinese Stoplight
Replacement lamps  (optional, if you want to get rid of the blinking, we used pricey LED ones so we didn't have heat issues)
Arduino Uno
TinkerKit Sensor Shield
TinkerKit Relay Module x 3 (one for each light)
DC Power Supply (we used a RS-15-15 which we dialed down to 12V)
Some small screws for mounting components (optional)
Small protoboard
A couple resistors (depends on application)
Wire

Step 1: The Guts

The lights that come standard blinked and so we replaced them with cool (i.e. not hot) LED lamps.

I don't suppose I need to go much through the wiring. It should be pretty straight forward