I'm looking for a tid bit more help regarding this. I am an electronics nub basically, but I've done some research.
I want to throw a 12V DC Avionics battery using the arduino.
If I were to use a relay such as this one:http://tinyurl.com/64jpjn
Control voltage range: 4 - 6VDC
Max. input current: 20mA
Load voltage: 3 - 52.8VDC
Load current: 0.01 - 2
Would I need to modify the R1,D1, or others in this diagram?http://www.arduino.cc/playground/uploads/Learning/relays.pdf
Also, I just wanted to clarify, can the Relay Power V+ on the right in the diagram come from the Arduino?
Edit: I should explain what I'm attempting.
I have a 12V battery powering a regulator which powers sensors. I want to have a tri-state switch - with states: Off, On, and Computer Controlled. When switched "On" the relay should switch the sensors on. When switched to "Computer Control" an event trigger on a computer (which is on a different power ciruit altogether) will decide the state of the sensors. The "On" state of the switch will be powered via the 12V of the battery, I suppose, whilst I'm unsure of how the arduino "Computer Controlled" will power the relay.
Just for the record, it wasn't my idea. I want a simple on-off switch NOT connected to the arduino. Don't ask me why I want a "Computer Control" setting, because it doesn't make sense to me either.