Hello,
I have a bunch of old LED strips that only have +/- which means no data input. I want to send data from PC to arduino via serial and use the values to control the strip when to turn on and off.
How would I do that without a data input ?
Could I just plug the + to a pin and control it this way ? With an external 12V 3A power source.
Thanks.
edit: I'm pretty sure that won't work so I have 2 other ideas.
One is to use a transistor, I have a few, but I've never worked with one before.
The other is to use my H bridge that I use to control a dc motor.
I think the same logic applies -> arduino gives 5v to one of the IN pins and one of the OUT pins releases the power from the external source. Yes ?
[u]MOSFET driver circuit[/u]
[u]Transistor driver circuit[/u]
You can leave-out the diode since you have a non-inductive load.
You can use the H-bridge, but it would be a good idea to add a series diode because you could accidently reverse the voltage.
In any case, the transistor, MOSFET, or H-driver needs to be rated for at least the current (amps/milliamps)required by the LED strip. A transistor will probably require a heatsink and a MOSFET might require a heatsink. If it's too hot to touch (or if the transistor or MOSFET dies 
) that's a good indication that you need a heatsink.
Thank you.