Add sound reactive LED's for any speakers! by samanen
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 :

 
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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!
hemmikarl says: May 25, 2009. 7:38 PM
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 says: Jun 4, 2009. 1:19 PM
wow. i didnt understand any of that, im sorry. i doubt the author understood you either. can you please repeat that?
hemmikarl says: Jun 5, 2009. 4:40 AM
the image is of a rectirior bridge.... it's main purpose is to lengthen the led's life.
4_diodes_bridge_rectifier.jpg
hoihoi151 says: Jul 30, 2009. 12:07 AM
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 says: Feb 28, 2010. 6:13 PM
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.

Phil
 
synthdust says: Aug 10, 2012. 9:53 PM
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.
tysonscott2002 says: Aug 23, 2009. 2:49 PM
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 says: Jul 5, 2011. 5:21 PM
you could also add an rc filter to that if you wanted
kool1zero says: Sep 21, 2011. 9:28 AM
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 says: Jun 11, 2009. 11:14 AM
what value would you use in the rectifier bridge? which diodes?
hemmikarl says: Jun 11, 2009. 4:28 PM
you can buy it rady made for about $1
marselsipod says: Jun 8, 2009. 9:34 AM
oh thanks
hunterbait93 says: Jan 28, 2010. 4:39 PM
 bwahahaha i have a new iPod nano 5TH GEN!!!!!!
eglesgorv says: Nov 27, 2011. 10:06 PM
And i Have the Steve Jobs Body that i stole from the morgue :D
samanen (author) says: Jan 29, 2010. 6:49 AM
And i have iPhone 3GS, "bwahahahaha!!" :D
Frag says: Aug 23, 2010. 11:30 PM
And I have an iPhone 4! Buahahahaha
jrbout says: Nov 15, 2011. 4:08 PM
and i have iPhone 4S hahahahahahbua
Nija says: May 20, 2010. 7:53 AM
 I have both bwahahaha
ivanjacob says: Jan 29, 2012. 6:07 AM
i have an istone 5 bwhuhahaha
curious youth says: May 14, 2012. 1:22 AM
who do you stone?
0xCyrusx0 says: Jul 22, 2010. 4:54 AM
I can actually use my hardware to the fullest extent, and in any way I desire.
biggunner says: Jan 11, 2011. 8:17 PM
i use my "hardware" in any way i desire too. just ask a woman. lol
MikeGlass says: Jun 10, 2009. 9:17 PM
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 (author) says: Jun 17, 2009. 6:09 AM
What resistor does? It brights up the led and helps the led to not heat or explode.
DNMEBOY says: Nov 3, 2011. 1:17 PM
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 says: Mar 3, 2011. 9:58 PM
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 says: May 29, 2009. 8:05 AM
banana!
marselsipod says: Jun 16, 2009. 1:46 PM
BIG bannana.
samanen (author) says: Oct 7, 2010. 8:15 AM
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.
[/offtopic]
T South says: Jul 28, 2009. 10:19 PM
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 (author) says: Oct 7, 2010. 8:12 AM
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 says: Apr 27, 2010. 2:38 PM
I have an LED that is .5 volts, would this work??
samanen (author) says: Oct 7, 2010. 8:09 AM
Yes.
melition says: Sep 23, 2010. 3:48 PM
i have a droid bwahahahaha... acutally thats a fail
phol23 says: May 8, 2010. 12:27 AM
 what is  your name  the music
dannohodad says: Oct 9, 2009. 8:37 AM
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.

Thanks,

One more newbie in the mix
Joa-King1495 says: Aug 25, 2009. 1:33 AM
what kind of LED did you use ?? How many Volts was it?
ATG says: Aug 7, 2009. 3:46 AM
wts the 1st song mate?.....nd yea grt instructable.....:)
pancho del rancho says: Jul 24, 2009. 1:43 PM
DO WE REALLY NEED IT I TRIED ONE WITHOUT IT AND IT GETS HOT FAST
samanen (author) says: Jun 17, 2009. 6:09 AM
If you liked it, can you vote please? :-) i need votes.
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