0

Possible Duplicate:
Power LED from headphone jack

New to electronics (I am a software guy) so pardon me if it's a very noob question. Can an iPhone headphone jack power a small LED? The LED hopefully can also change it's colours based on the signal so I am guessing there's some going to be some sort of logic component to it.

Also, where can I get started with the hardware side of things?

Thanks

Community
  • 1
0xSina
  • 117
  • 1
  • 2
  • Hi oxSina, and welcome to EE. When you start typing the title to a new question you get a list of possibly related questions. Next time please check the list. It appears that your question has been asked before. – stevenvh Jul 20 '12 at 17:24

1 Answers1

0

You will need to use an op-amp or a simple transistor based level shifting circuit to light up an LED from headphone jack. The amplitude of the headphone output is simply too low to drive an LED. Look here, http://en.wikipedia.org/wiki/Line_level. Also hook up an oscilloscope to your iphone output to make sure of the voltage levels.

And how would you want to determine the color of LED? It it is just the signal level, that could be easily accomplished with a comparator. If you want more sophisticated discrimination, like pitch or tone for example, you need signal processing circuitry.

Aamir
  • 113
  • 5
  • 1
    I doubt this will help OP any. He says he's new to electronics. You'll have to give some details. – stevenvh Jul 20 '12 at 17:37