interfacing digital pin to control 12 volt device

Forum 2005-2010 (read only) Hardware Interfacing
1

I have completed my code, well all i'm going to do with it for now, and have setup 4 led's hooked to 4 digital out pins on the mega.

everything functions as I want.

In the current setup, each digital pin can supply enough power to light my led.

However, Each LED will be replaced with an array of 24 led's that MUST be powered by +12 volts.

so how in the world do i control the 4 arrays in place of the 4 single led's without toasting the arduino.

Is there something simple I can buy at radio shack or even autozone to tell the +12 volts to only be supplied when the arduino gives its 5 volts of power to that pin.

I know i've asked a lot of stupid questions, i'm just new at this, and learning, once I know this one part, I will be busy for a week or so soldering led's.

2

You need a relay.
http://electronics.howstuffworks.com/relay.htm

3

so, would something like a cheap 3 pin horn relay for a car work?

i'm assuming I would need one per led array as well?

4

I think "yes" is the answer to both questions.
I also think a solid state relay is also suitable, given low currents your project probably require.

5

thank you.