Bear with me because I have no idea if this is even feasible or not. Plus I know a little about electronics, but not a whole lot. My current project is wiring my bicycle with lights. I have some lights already hooked up and wired to a switch box, but the idea of automation intrigues me. You know those awesome Christmas light displays that are programmed to music? That's what I'm researching. Obviously I need something portable, so I'm looking at the Arduino Uno and it looks all fine and dandy, except for the part that says:
Each of the 14 digital pins on the Uno can be used as an input or output [. . .] They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA
This simply won't do as each light (so far) runs off of a AA battery pack that provides either 12v or 6v (depends on the light). I'm planning on getting a 12v 5Ah SLA battery to simplify things, but that's neither here nor there. So here's my hypothetical situation:
- Connect relay to Arduino (what kind of relay would I even need?)
- Connect external battery to relay
- Connect lights to relay
So basically I want the Arduino to just control the on/off states on the relay and not provide any direct power to the lights themselves (since that won't work anyway with the low voltage and current). It seems simple enough, almost deceptively so. Am I missing anything crucial? Thanks in advance.
EDIT: I should clarify that I tried googling this stuff before posting here, but all the diagrams and charts and jargon is altogether too confusing for me to sift through.