3 Simple Ways to
Share What You Make

With Instructables you can share what you make with the world — and tap into an ever-growing community of creative experts.

PhotosPhotos

Share one or more photos of a project, recipe, or whatever you've made, quickly and easily.

Get Started

Learn more & Get Tips

Step by StepStep-By-Step

Share your step-by-step photos with text instructions of what you made so others can do it too!

Get Started

Learn more & Get Tips

VideoVideo

Share your how-to video. You'll need your embed code from a video site such as YouTube.

Get Started

Learn more & Get Tips

Favorite

Sound Synchronized LED Video Tutorial

video Sound Synchronized LED Video Tutorial

9 comments

Sep 7, 2011. 8:35 PMnodoubtman says:

What is the role of TIP31 transistor PNP here ??

Thank You!
CYa!

Jan 4, 2012. 10:52 PMsamalert says:

whole heart of this project is TIP31 :)
TIP31 directs the current based on the signal received more the sound more the pulse it directs to led

so what u actually see the blinking based on sound is all controlled by TIP31 :P

more on that TIP31 a/b/c all work fine for this synchronization

May 18, 2011. 8:13 PMrclingan says:

I'm having trouble following 100% on the video where all the cables go. I have made a diagram of where all my cables are going, will you let me know if it is correct?

1(green):LED [Anode is top, Cathode is bottom]
2(yellow): TIP31 transistor.
3(purple):Cable from TIP31 to ground.
4(Light blue):Cable from LED anode to positive.
5(dark grey): Gold cord from headphones to ground.
6(light grey): Red cord from headphones to TIP31.

Is there anything wrong with this setup? when i first tried it, the LED would come on but it would stay 100% lit, now it wont light up at all. All I can think to do is switch 5 and 6, and when I tried that nothing happened. Let me know, thanks!

May 19, 2011. 5:48 AMzatek (author) says:

http://www.instructables.com/files/deriv/FLY/8U5P/G145S9RT/FLY8U5PG145S9RT.LARGE.jpg

The cathode of your LED is one pin too far down.
Other than that it looks good. Make sure you've stripped the audio cord insulation.
Good luck!

Jan 10, 2011. 2:11 PMwotot2 says:

Hey i have a few questions, if you could please answer.
I have a speaker system, and thats what im trying to sync the leds to, so how do I do that?
Also... I'd like to use like 20 or so leds for each channel. is that possible?
Does the volume have to be maxed out for this to work?

Jan 16, 2011. 6:10 AMzatek (author) says:

To sync leds to a speaker system, you must hook up the leds to the same amp as the speakers are connected to. You can do this with standard audio cables and just put them in the same channels as the speakers. Depending on your speakers you might want to install a diode in the circuit. It is possible to use whatever quantity of leds, provided you have enough power. I'd suggest a power supply for 20+ leds. And the volume shouldn't have to be maxed out if all the soldering points have good contact.

Dec 7, 2010. 11:55 AMleweshdu59 says:

Can we make this whit 2 led ?

Dec 7, 2010. 2:40 PMzatek (author) says:

Yes, just wire them in series, you can also have one for each channel. In both cases you should check out my profile for the in-depth instructable.
Thanks.

Dec 3, 2010. 10:49 AMmossDboss says:

www. uploderx. net/ dphrag/ SCHEMATIC1___PAGE1444.jpg

keep the coolness coming above is the link to a schematic to sync 3 LEDs to different frequencies. I have tried two the circuits, but i do not have very many different resistors and capitors. I did find that 1k resistors and 10uF capicators worked well also a 103k ceramic capacictor was used instead of the 10uf one.