Introduction: Add Sound Reactive LED's for Any Speakers!

So, there's what you need :)
1-10 LED's, Any color, any size (I used 2x 5mm red LED's)
Drill & LED-sized (5mm usually) drill bit
Little rasp to file LED's holes to fit with your LED's
Speakers , I used Creative TravelSound -speakers
Screw driver (if required for removing the speaker boxs cover)
4 Wires (1-30cm, that's about your speaker's size and where do you want to place the led's)

So, let's get started! :)

Video about all this :

Step 1: Select the Place for LED's

You need to select the place for LED's, and mark it with a pencil. Check that you have space inside the speaker box for leds!

Step 2: Drill Holes to the Marked Places

Drill holes to the marked places where the LED's comes. Use rasp to make hole to fit with the LED.

Step 3: Solder

You need to solder your wires to the speakers + and - sides, the sides with the LED's does not matter.
Then solder your LED's + or - side to the wire, and solder the other wire to the other LED side too. Do this step again with the another speaker.

Step 4: Place the LED's

Put your LED's to the holes you drill'd. Check that your wires does not touch each other, or your speakers does not work!

Step 5: Finishing

Put case back together, and enjoy!


hemmikarl made it! (author)2009-05-25

I recommend that you either get a rectifior bridge or solder 2 diodes in paraell with anode to cathode sense the sound output to the speakers is generally a sine wave

marselsipod made it! (author)marselsipod2009-06-04

wow. i didnt understand any of that, im sorry. i doubt the author understood you either. can you please repeat that?

hemmikarl made it! (author)hemmikarl2009-06-05

the image is of a rectirior bridge.... it's main purpose is to lengthen the led's life.

hoihoi151 made it! (author)hoihoi1512009-07-30

lengthen the led's life. lol led's last for over 5 years of continuous use and they cost less than $1 each. i dont really see the point. Oh and sine wave is very very rarely outputed through a speaker. Sine wave is a flowing wave of sound for an individual frequency. when more than one frequency is played, the wave form becomes altered into a mess between sine, square, sawtooth and triangle wave forms. your speakers and led's will be safe

sammons made it! (author)sammons2010-02-28
OK, for those people that don't want to be told the wrong information, I'd like to clarify: Sine waves are the basic form of sound waves. Square, sawtooth and triangle waves are not part of any music. If you send a square wave to a speaker you are likely to blow up your speakers as speakers don't like DC (direct current). What hoihoi151probably meant is that you never get a pure sign wave through your speaker. It is always a mix of many sign waves of varying frequencies.  The point of using a bridge rectifier is to make the LED light up while the sine wave is in the -ve voltage region of the cycle, i.e. making the AC (alternating Current that is fed to the speaker) into DC (Direct Current) as LEDs are DC components. Also, many high-power LEDs do not like to be fed reverse voltage. As the name suggests they are Diodes, however many are sensitive to reverse voltage and does shorten their life.

synthdust made it! (author)synthdust2012-08-10

Not sure what you mean by; "Square, sawtooth and triangle waves are not part of any music." I play synthesizers and these three wave forms are generated by the oscillators as a base for most additive synth sounds. As I understand it, there is no such thing as pure sine wave in nature.

FrostEnergy made it! (author)FrostEnergy2009-08-23

yes, it does lengthen the led's life. because putting them under this kind of stress shortens it. if not simply burning them out, and they may be cheap, but the hassle to have to change them out, simply isnt worth it, it makes more sense to prevent the problem first.

aduy made it! (author)aduy2011-07-05

you could also add an rc filter to that if you wanted

kool1zero made it! (author)kool1zero2011-09-21

That partially defeats the purpose, the goal being volume (higher voltage from the top of the ripple) lights the leds. The filter cap charges and then discharges slower causing it to stay lit longer and kind of fade out (which might ne desired)

alienhoodlumz made it! (author)alienhoodlumz2009-06-11

what value would you use in the rectifier bridge? which diodes?

hemmikarl made it! (author)hemmikarl2009-06-11

you can buy it rady made for about $1

marselsipod made it! (author)marselsipod2009-06-08

oh thanks

hunterbait93 made it! (author)2010-01-28

 bwahahaha i have a new iPod nano 5TH GEN!!!!!!

samanen made it! (author)samanen2010-01-29

And i have iPhone 3GS, "bwahahahaha!!" :D

Nija made it! (author)Nija2010-05-20

 I have both bwahahaha

ivanjacob made it! (author)ivanjacob2012-01-29

i have an istone 5 bwhuhahaha

curious youth made it! (author)curious youth2012-05-14

who do you stone?

0xCyrusx0 made it! (author)0xCyrusx02010-07-22

I can actually use my hardware to the fullest extent, and in any way I desire.

biggunner made it! (author)biggunner2011-01-11

i use my "hardware" in any way i desire too. just ask a woman. lol

Frag made it! (author)Frag2010-08-23

And I have an iPhone 4! Buahahahaha

jrbout made it! (author)jrbout2011-11-15

and i have iPhone 4S hahahahahahbua

eglesgorv made it! (author)eglesgorv2011-11-27

And i Have the Steve Jobs Body that i stole from the morgue :D

MikeGlass made it! (author)2009-06-10

Is this your Youtube video above? I love this instructable. I am planning on doing it to my car. What I would like to know, is what exactly the resistor does. Does it increase the sensitivity for LED activation? I just have a stock sound system in my car, exactly how loud would the music have to be before I got some LED action going on (with resistor added).

samanen made it! (author)samanen2009-06-17

What resistor does? It brights up the led and helps the led to not heat or explode.

DNMEBOY made it! (author)DNMEBOY2011-11-03

Actually a resistor will decrease voltage to an LED, since LED brightness increases as the voltage increases then adding a resistor would cause the brightness of the LED to decrease since the resistor will lower the voltage going to the LED.

The purpose of the resistor on an LED is to prevent them from burning out. I have burned out many LEDs but have never seen one explode.

Davvik made it! (author)2011-03-03

I would not recommend soldering a diode directly across speaker terminals. A speaker offers resistance against the amplifier, an LED allows electricity to flow freely across itself. You are essentially shorting out you amplifier which can cause it to overheat and wear out quickly.

What I would recommend is looking into a transistor, something like the TIP31A, or a MOSFET. The Mosfet is probably your best bet since it is voltage driven instead of current driven.

linkyta made it! (author)2009-05-29


marselsipod made it! (author)marselsipod2009-06-16

BIG bannana.

samanen made it! (author)samanen2010-10-07

Regular size Finnish banana ^^
Acutally, not finnish :D they just sell this size of bananas in Finland. Doesn't look bigger than a normal banana in my eyes.

T South made it! (author)2009-07-28

Wow. I've been trying all of these LED music syncing projects, and none of them have worked up until this point. And go figure, this amazingly simple setup works like a charm. The only question that I have for you is what exactly the "complicated" circuit is that you added in to make the LED brighter. I'm assuming you bought it somewhere, so more information as to what it is and where you bought it would be greatly appreciated. Thanks and GJ.

samanen made it! (author)samanen2010-10-07

Thanks a lot! :) Hehe, it's magic ;P
I used .5 (right side) and 1.0 v (left side) leds, i think. Can't remember it anymore. (<- for everyone who asked)
My leds are waay more brighter than it looks in the picture.

Goalie1 made it! (author)2010-04-27

I have an LED that is .5 volts, would this work??

samanen made it! (author)samanen2010-10-07


melition made it! (author)2010-09-23

i have a droid bwahahahaha... acutally thats a fail

phol23 made it! (author)2010-05-08

 what is  your name  the music

dannohodad made it! (author)2009-10-09

Hello.  Has anyone done more work on a circuit that activates leds from guitar/ bass amplifiers?  I've seen some of it mentioned, but nothing specifically for this idea.  I want the signal from my bass to activate the lights obviously.  I have made a simple circuit that worked with a long string of leds, but it's very crude and needs to be cranked up on my amp to activate.   
Looking for any new ideas specific to this idea.


One more newbie in the mix

Joa-King1495 made it! (author)2009-08-25

what kind of LED did you use ?? How many Volts was it?

ATG made it! (author)2009-08-07

wts the 1st song mate?.....nd yea grt instructable.....:)

pancho del rancho made it! (author)2009-07-24


samanen made it! (author)2009-06-17

If you liked it, can you vote please? :-) i need votes.

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