Need help with simple audio to flashing LED project

Discussion in 'The Projects Forum' started by silverslik1, Apr 30, 2010.

  1. silverslik1

    Thread Starter New Member

    Apr 30, 2010

    I'm trying to build these projects: Music LED Light Box or Blinking leds (they are really the same project) that take audio and make an LED or a series of LED's blink with the beat or rhythm. I can get it to work, except the LED's are very low and are very dim and do not blink with the intensity in the video. I am using two 9 V batteries in series at around 17V and the LED's are fine because if I connect them to a source and a resistor, they get around 20-30mA of current which is ideal. In the setup I have now where they are very dim, they get only around 1-4mA MAX which is the problem for obvious reasons.

    Anyone know a reason which could be giving me such a low amount of current? I've tried changing the voltage, but when I had 9V's in there, it did not make much of a difference and when I have 17V in there, it is still at the same intensity.

    I have used a resistor, right now, it has a 280 Ohm resistor (a 100 and 180 in series) from the source of the transistor to the start of the LED's that are in series and it does not help only hurts. When the resistor is in series, it makes the current go under 2mA. Do you have a schematic of the project you made?

    I've been looking at videos and drawings all day and I can't seem to figure out why mine is the only one doing it. I've tried rebuilding 4 times with 2 different guides and a Youtube video- I consider myself to be an avid circuit builder as well!

  2. bertus


    Apr 5, 2008

    The circuit shown on the instructables is to simple to work.
    I made a sound to light some time ago with (our member) fenris.


    The lamp can be replaced by the leds with the corrosponding current limiting resistors.

    Last edited: Apr 30, 2010
  3. hobbyist

    AAC Fanatic!

    Aug 10, 2008

    Here is a very simple one I made for someone else on this board who wanted to do something similar to what your doing.

    He wanted to use an IPOD, this circuit might work for your aplication.

    ipod leds.jpg
  4. Wendy


    Mar 24, 2008