Arduino fader

[dannyeatworld]

Hi guys,

I'm trying to use a 12V source to make 10 LEDs fade (or breathe, if you will) with a on/off switch. When the switch is on, the LEDs fade in and out in unison, when the switch is off, the LEDs stay constantly on.

Found this: http://cachefly.oreilly.com/make/jg_arduino.pdf

My question is, how do I use the Arduino take in 12V? The tutorial seems to like 9V. Is 12V even possible? How can I output to 10 LEDs from the pins? Right now I have these running off of 12V, each at 3.3V and around 30mA.

Thanks!

[Franklin97355]

You need to drive the LEDS with a transistor and since you are wanting to fade them you need one that will switch fast. I'm not well versed in part numbers but others here probably can help.

[dannyeatworld]

Thanks for the reply, Franklin. Do you mean I need a transistor at the output the Arduino as the input of the LEDs?

[Franklin97355]

Yes, the transistor base will go to the Arduino with the led, resistor going between the transistor and 12v. there are many circuits of this out there.