License: Attribution Non-commercial Share Alike (by-nc-sa)
Intro: Music LED Light Box
My original LED light cube got allot of reactions. Some of them where about making the LED's react to music. This did sound very interesting and I found some
instructables on here.
Unfortunately I found it very hard to understand those instructables. In my opinion they weren't explained well enough and even some circuits weren't correct.
That's why I though I build one and make an instructable of it. I tried to make this instructable so easy, that everyone with or without any experience can make one!
If you make one, don't forget to share your end result photos and movies with us.
Below you'll see the end result of my Music LED Light Box.
The movie is shot with my Canon Digital Camera, in the dark. My camera can't handle the fast switching between light and dark very well. In reality the effect is even
nicer then on the video.
Before people go asking who's music or what songs these are in this video, these beats are made by my brother. :)
You can visit his YouTube channel for more information and songs.
step 1: Materials & Tools
To make this Music LED Light Box you can use many different things and build it different ways.
In this instructable I'll explain how I made it, a very simple way.
- 12v Adapter (a battery can be used as well)
- 3.5 jack headphone cable.
- tip31 transistor (this is the key to the wh ole project) - $0.50
- 5mm LED's (the color or amount is totally up to you, 1 LED per 3v. I used 12v, so 4 LEDs) - $0.28
- A4 acrylic sheet - 3mm thick (also known as 'plexiglass') - $2.00
- Fine sandpaper (I used 400) - $1.00
- Electrical Wire
If you see a price above, that means I bought it. The rest I just ripped of some old junk. The 12v Adapter was from an old wireless headphone and the 3.5 jack plug is
from another old headphone.
- Jigsaw (also a Jeweler Saw can be used. But that's really hard to get straight lines)
- Glue Gun (hot glue, other glue to glue acrylic is possible)
- Drilling tool
- Solder tool (optional)
Ones you've got this stuff you're ready to begin!
1. 12v Adapter. Be sure to read step 5 to find out more about this or any other adapter!
2. Ripped this from the switch as well. It's the part where the adapter goes in to and a toggle switch. Eventually I didn't use the toggle switch.
3. 5mm LED's - Blue - Water Clear
4. TIP31 transistor. To be precise, this is a TIP31c transistor. But from what I've read on the internet, a TIP31a and TIP31b can be used as well.
5. 3.5 Jack plug. Who doesn't have old headphones lying around :)
6. Sandpaper - 400
7. A4 Acrylic sheet 3mm - Also known as 'Plexiglass'.
step 2: Preparing the box
From the acrylic sheet we're going to build the box.
1. Draw out the plates for the box on the acrylic sheet (photo 1). My longer plates are 15cm x 5cm. And the squares are 5cm x 5cm . Of course you can use any size for
a box you want.
2. Use the jig saw to cut the plates from the acrylic sheet. Be sure to do this as perfect as you can. Because all plates need to line up nice with each other (photo 2).
If the plates don't turn out to be equal, you can sand the sides till they all fit nice.
3. Get the drilling tool and use a drill bit that is the same size as the thickness of the headphones cord (photo 3). Then drill another hole for the adapter to go though.
When you're drilling, do this very carefully! You don't want to hurry, else you might put too much pressure on it and break the plate.
1. Hole for the audio cable.
2. Hole for the adapter.
step 3: Frosting and Diffusing
To get the nice 'glowing' effect with the LED box, we need to have a 'frosted' look on the box and need LED's that are diffused.
I only could get my hands on water clear acrylic sheets and water clear LED's. For all those who have the same, continue with this step.
If you already have frosted acrylic (opal acrylic) and diffused LED's, then you can continue with step 4.
1. G et the fine sandpaper (400) and place it on a table, with the sanding side up. Get a plate and rub it over the sandpaper in a circular motion. If one side is frosted
enough, turn the plate over and do the same with that side.
Now you'll have a nice frosted looking effect we need (photo 1 and 2 to see the difference).
2. Do the same with the LED's. Sand the LED's until they get the nice diffused look (Photo 3,4 and 5).
Photo 5 shows you 1 diffused and 1 water clear LED hooked on a 3v button cell.
1. LED after sanding: Diffused LED
2. Water Clear LED's.
1. The left LED is diffused and the right LED is still the original water clear LED.
step 4: Building the box
Now we've got the plates for the box, we need to put them together.
Before you go and glue parts together, make sure first they fit nicely onto each other. We need all parts to fit nicely.
1. After fitting the plates get the glue gun and glue the first 3 plates together . If you have some trouble holding the plates together before gluing, you can use some
tape to hold them together. This way you can put the glue on more relaxed .
After gluing the 3 plates you should have something like photo 2
2. After the glue is dried, it's time to glue in the side plates. First place them and see if they fit nicely.
If not sand the sides a bit so everything fits nice together. Then glue them on their place.
The last (bottom) plate will not be attached yet. We need to put the whole circuit on the bottom plate later and then put it in place.
At this moment you should have something like photo 3 and 4.
step 5: Preparing the circuit
Since I have no experience in electronics whatsoever, this was the toughest part for me to find out.
Other instructables had no good explaining on this subject.
So for everyone who's new to this electronics stuff and have no idea what they're doing, here is some explaining for the circuit.
1. How many LED's to use?
The average LED needs 3v to work. If you are going to put the LED's in series (like I did) you need to calculate how many LED's you can use with your adapter. The
formula you can use is adapter output voltage / LED voltage = Total LED's
So if you use a 12v adapter with the 3v LED's its: 12 / 3 = 4 LED's
You can also put LED's parallel in the circuit. But I'm not getting into this, just so that this instructable stays simple and easy to understand for everyone. Let's just focus
now on the LED's in series.
If you want to experience with more LED's, you can always calculate your LED's and resistors here.
2. The real voltage on a adapter.
Before I went building this circuit, I thought it would be useful to measure the real voltage on the adapter. The sticker on the adapter (photo 1) says the output 12v. But
once I hooked it up on my multimeter, it shows that the actual output is around the 18v (photo 2).
So that means I can calculate the LED's again: 18 / 3 = 6 LED's.
Since I'm going to make the LED's in series I can use 6 LED's in my circuit.
3. The 3.5 audio jack plug
Which wire is what? That's what I was asking and trying to find out.
As you can see on photo 3, the plug itself has 3 metal parts, and 3 wires in the black protective layer.
On the photo I explained which wire is what.
Now with this information you can go to the next step, building the circuit.
step 6: Building the circuit
Many people get scared when they see all those weird circuits with those symbols on it. Having no clue what they mean.
That's why I made a instructable friendly circuit image :) See photo 1.
1. Make sure you have all the materials to make the circuit. And enough electrical wires to connect all the components.
2. Before we build the circuit, we first need to put the audio cable through the whole in the back.
3. Build your circuit, and test it out. The best way to test it is through your audio output from your computer. Make sure the audio on your computer is set to 100% and
then test it.
Circuit : The positive pole from the adapter goes to the positive leg of the first LED. Next the other 5 LED's follow. Hook the negative leg from the first LED to the
positive leg of the second LED. Hook the negative leg from the second LED to the positive leg of the third LED, and so on. The negative LED from the last LED goes to
the center pin of the TIP31.
Then hook the right pin of the TIP31 to the negative pole of the adapter.
All there's left now is to hook up the audio cable. Hook the red or the white wire from the audio cable on the left pin of the TIP31. And connect the ground wire from the
audio cable to the right pin of the TIP31.
For better details please see photo 1, the circuit.
4. If your circuit works, solder all components together so the circuit stays together nice and strong and wont fall apart.
When done with these steps it's time to finish up!
If you have trouble getting the circuit to work, you can try to set it up first on a circuit board.
Carlosserious was so kind to make a how-to video on making the circuit, click here for the video .
1. I've attached the white wire (right channel) to the TIP31. Since I won't use the
red wire, I cut it of.
2. Please don't get cunfused, this is the backside of the TIP31!
step 7: Finishing up
We've now got all the parts we need. All we need to do now is put the bottom part into the cube to make it a whole cube.
1. Use the glue gun again to put the connector for the adapter right behind the hole. Tip: Plug the cable in before gluing. This way the connector will always be on the
2. Sand the sides of the bottom plate so it fits snugly into the bottom. You just want the bottom plate slightly bigger then the hole it fits in. This way, once you put it in
there, it will get stuck and won't let go while moving the cube. We won't glue the bottom, in case we need to open it for some reason. So make sure the bottom fits in tight.
Now plug everything in and put your music on max and enjoy!
You can change this project as much as you like. Use any LED's you want, create the box that fits the best on your desk, etc. You can also build the cube from my
previous instructable .
I used photoshop to show you how different colors would look like (photo 7 ).
I tried to make this instructable the way so everyone can understand it. I'll try to answer them all. If you want to make one and get stuck, we'll try to get through it together.
If you have any questions please don't be shy and let me know.
1. You can make a knot here so when accidentally pull the cable, nothing will
break off inside.
rock (video) by
blinking to Blinking LEDs Blinking leds by How to make a riverreaper MAKE a mind Cool laptop LED
music LED to Music by pasteler0 fast blinking control
LED bike light lights by mrworf
(video) by Tesla1138 BlinkLED by hypnosis dream
artcobain chipmonger by comodore machine Cheap
50 comments Add Comment view all 403 comments
xelex says: May 12, 2010. 8:27 PM REPLY
Got a question, how would i go about using this in my car? Cause i wouldnt be able to plug it into outlet. Ive got a sub im wanting to hook it up to, and an
amp. So could i just run the power straight through the amp? If so will you explain this, as i am a complete noob with wiring and everything
legomitch02 says: May 13, 2010. 1:13 PM REPLY
well I think you would frist need to go out and buy a good ole fashion book and get to studying electronics because I dont want to risk breaking a perfectly
good car amp!
xelex says: May 13, 2010. 4:35 PM REPLY
yea, your prob right, i know theres a way to wire stuff up to the amp, just not sure, thanks anyways
jjeellee says: May 13, 2010. 2:02 AM REPLY
where can i buy tihis stuff??????
if you now where e-mail me please email@example.com
NostalgicStone says: May 12, 2010. 2:06 PM REPLY
This is awesome!
I'm going to have to give this one a go sometime very soon :)
great Instructable, love the illustrations, good job all around!
geo bruce says: May 11, 2010. 8:38 AM REPLY
i works but is it possible to make it brighter
legomitch02 says: May 11, 2010. 4:06 PM REPLY
I know it can be louder I just dont know how :P
geo bruce says: May 11, 2010. 11:24 PM REPLY
I've tried to set u a higher voltage but it doesn't make it brighter I think an otther transistor than tip31c
your dog says: May 9, 2010. 8:55 PM REPLY
is there a more sensitive transistor? When I try and use it with my iPod, it doesn’t send a strong enough current to open the transistor. But when i tried it
with by boombox on full volume, it worked.
Or possibly, can i amplify the voltage in the audio cable somehow?
Also, what do you use for the sound since the headphone jack is being used?
Thanks for help!
legomitch02 says: May 10, 2010. 12:53 PM REPLY
1.)Im not exactly sure if it would work but its worth a try....Lets say that you have 6v of electricty coming in. And you wire three 3v leds in a parallel so
there is 3v of unused current. Then you put a 50 ohm resistor infront of the leds to limit the current to 3v. The math is (6v - 3v) / 60 ma (total current
draw of leds) which = ~50 ohms. So when the transitor sends the proportional voltage to the leds in response to the ipod the leds actually recive a higher
voltage there by making them more responsive. Sorry if this doesnt make any sense if you want i can explain bettter later but for now.......
2.)I had to use a head phone splitter to get audio to speakers you can use any of the ones in the following links: www.radioshack.com/product/index.jsp
your dog says: May 10, 2010. 5:51 PM REPLY
I"m not very good with electronics; a digram would help.
and yes, i was using a headphone spliter but it only took away more power
legomitch02 says: May 10, 2010. 4:31 PM REPLY
I forgot to add that im not an expert in electronics so wait until someone else confirms this before thinking its 100% accurate
trehacks says: May 3, 2010. 6:33 PM REPLY
is this light blinking because its reacting to sound?
legomitch02 says: May 10, 2010. 4:54 PM REPLY
to be specific the postiive lead from the headphone jack provides a small current which switches the internal positive silicon boron mixture which causes
a proportional current going from the battries to the leds. so no the leds are not responding to mechanicle waves, but they are in fact responding to
the current traveling trough the head phone wire.
magiccowy says: May 3, 2010. 4:11 PM REPLY
Would it be possible to hook up the leds in parallel (+to+ -to-) so that i can run more leds of a smaller poower source? or do they drain to much current?
I was led to beleive they used almost no current
legomitch02 says: May 5, 2010. 12:53 PM REPLY
im 100% sure that you can put LEDs in a parallel connection, but it depends on what the current of you battery is. for example most AAs have a current
of 700mah and most LEDs use 20 mah so..... 700/20=35 therefore the most i would put in a parallel is somewhere near 35. as for the life of the battery it
may be shorter but hey 100 AA on ebay are like 24$
i also thought id share a quick pic for you :D
magiccowy says: May 10, 2010. 4:09 PM REPLY
Thanks! Like i thought i just needed confirmation
legomitch02 says: May 10, 2010. 4:29 PM REPLY
your dog says: May 7, 2010. 3:16 PM REPLY
would this be the right transistor?
legomitch02 says: May 8, 2010. 8:08 AM REPLY
thats the one i used :D
charles_d says: May 4, 2010. 12:28 PM REPLY
Thank you for the great tutorial, it works perfectly!
However; would it be possible to add an Op Amp between the audio source and the circuit? Because it only works when my audio output is at full blast, and
the LED isn't as shiny as it could be in a simple circuit.
Dou you think that this system could be combined with a microphone (being the audio source)? Hence using an op amp because a microphone signal is
very low right?
Final question: what is the voltage range the tip31can be used?
Sorry for the mistakes, english isn't my maternal language :)
legomitch02 says: May 5, 2010. 12:26 PM REPLY
I'm also experiencing low lighting even on 100% an Op Amp would be nice, what ever it is :P
legomitch02 says: May 2, 2010. 7:20 PM REPLY
Is it okay if i use a 3.7v lipo battry for each LED?(as in having a 4s lipo for 4 LEDs) Also, could you split the audio jack into 2 and have one going to LEDs
and the other going to speakers?
Thanks in advance ,
neonix says: Mar 1, 2010. 3:06 PM REPLY
Argh, I tried this today and I've come out with nothing but frustration. I have no idea why it doesn't work. I understand the instructions (they are very good!)
and the excellent diagram. I followed it exactly, but for some reason, my LEDs don't light up to the sound. I'm sure the cab;e I'm using works because I've
used it to output to speakers.
I am using an assembly of 8 AA's for 12V instead of an outlet. Something weird about my circuit is that when I tested to see if the transistor was at fault, I
connected the circuit directly to the battery assembly and they lit up momentarily before being fried. Maybe my LEDs are lower voltage? I don't see why; they
are standard LEDs I got in an assorted bag from Radioshack.
But that's not even the main problem. The lights do not even get to burn out when I have the transistor in the circuit. I know I wired it properly. I tried two
different ones of the same model number. Got them at the Shack too. The package simply says "TIP31" and does not specify a letter after, but on the
transistor itself is printed "TIP31AG." Maybe that is why it doesn't work?
Any help would greatly be appreciated.
rufus-spqr says: May 1, 2010. 4:00 PM REPLY
Be careful with the color of LEDs you use for this. Different color LEDs have different forward voltages. White, blue and green are normally between 3.3
and 3.0 V per LED. Red and yellow and orange LEDs have lower forward voltages. That means(LEDs in series):
4 LEDs, white: 3 Volt each = 12 V .. this setup is fine
(yes, yes.. I know.. on the package of the LED it might say Vf=3.3V... BUT.. as soon as they become just a bit warm, Vf drops.. to about 3.0 to 3.1 V).
The point is, runnig 4 white, blue or green LEDs in series from 12V is OK, as long as the supply is stable!! If your "wall wart" transformer power supply
hands out 12.5 V or more... they will overheat and not last long.
Other LED colors:
4 LEDs, red: 2.2 Volt each = 8.8 V .. If you drive these 4 LEDs directly from the 12V battery or power supply, just as the original diagram suggests,
without a resistor, then they WILL go dead very soon.
To avoid these pitfalls, you can add a resistor in line (in series) with the LEDs. That resistor should be about 180 Ohms for red, about 150 Ohms for
yellow or amber LEDs, and about 47 Ohms for white, blue, pink and green LEDs.
smithlee says: Mar 4, 2010. 12:19 AM REPLY
I no idear what I can not upload the schmatic ,so...
if even not working , you can add capacitance (about 10,000p) between transistor B point & signal input (audio outlet)
tip31 pin configuration
smithlee says: Mar 3, 2010. 11:35 PM REPLY
add one resistance(about 4.7k~47k) between transister C &B point
smithlee says: Mar 3, 2010. 11:25 PM REPLY
must add one resistance
neonix says: Mar 4, 2010. 12:23 AM REPLY
It's funny I have two packs of resistors just sitting on my desk and one of them happens to be 47k. I tried it with my two AA battery, one LED
assembly, but it didn't change anything.
Do you mind if I bombard you with questions? :P
What's the logic behind adding a resistance?
How come the range is so large (4.7k to 47k)?
Was that meant towards my 8-battery assembly? Or should it have had the same effect with two batteries and one LED?
Thanks for your help btw :)
smithlee says: Mar 4, 2010. 1:21 AM REPLY
you are welcome, I can answer any question about electric.
add resistanct can help the transistor working.
range so large. because the audio outlet volume & the circuit total load( min R to get much power ; max R to get a litter power)
series 8-battery you can get DC 12V,use DC12V can help you easy to work but careful you must series 4~8 LED(you can series 8-led ,if it not
work or dark then to decrease LED .it is safe way)
motadacruz says: Mar 1, 2010. 4:09 PM REPLY
What is your audio source?
Because when I tried my iPod, nothing happend. When I hooked it up to the audio of my computer, it worked like a charm! If you test it on your computer,
don't forget to put the output audio on 100%.
neonix says: Mar 1, 2010. 5:56 PM REPLY
I was using my ipod, but I just tested my computer on full blast and still nothing. :/
eightnine says: Mar 1, 2010. 6:05 PM REPLY
Something isn't right. Okay, so you said that you are using AA batteries to power the circuit. And you're sure that you have them hooked up in
series? (positive to negative, negative to positive, etc)
If you can, snap a photo.
neonix says: Mar 1, 2010. 6:44 PM REPLY
Sure, here's a shot of the whole thing, a closeup of the transistor, and my battery.
SoundTechie2007 says: Mar 12, 2010. 6:26 PM REPLY
Hey, I actually noticed that you're using coated wire on the audio in of your transistor. There is a red color to your wire. This red coat
needs to be stripped off (sandpaper works great) in order to take this layer off. I don't even think that your transistor is getting a signal the
way you have it set up now!
neonix says: Mar 13, 2010. 2:40 PM REPLY
Wow, good catch! I actually found a wire that has thicker, regular uncoated copper and it works beautifully! I even got this thing to
react to my iPod. Now to assemble a nice box..
Thanks SoundTechie, motadacruz, smithlee, and everyone else who helped. I appreciate it a lot!
smithlee says: Mar 4, 2010. 2:29 AM REPLY
difference color LED need difference power, so difference color LED in one loop is not good ideal.
motadacruz says: Mar 2, 2010. 1:28 AM REPLY
You made 1 mistake there Neonix.
You've got 4 batteries in series that give you 4x 1,5v, so thats 6v total.
In your LED series you've got 4 LED's that need 3v each, so a total of 12v is needed there. You do not have enough power there.
Just test your circuit with 1 LED and 2x AA battery. This should give 3v from to battery to the 3v LED. This should work.
If this works, you can put the LED's parallel instead of in series.
neonix says: Mar 2, 2010. 9:41 AM REPLY
No, there's 8 batteries in that holder. You just can't see because I chose the worst possible angle for the picture. So that's not the
@Spurr, I don't think I burnt them out. After my testing my first 4 LEDs and them not working, I connected the series directly to the
battery w/o the transistor, and then the LEDs burnt out. So I swapped all the LEDs, which I tested on another device beforehand. So
they aren't the problem either.
I'll try a parallel circuit later when I get home and let you know how it goes.
eightnine says: Mar 2, 2010. 12:28 PM REPLY
Well, it looks good to me. It looks like you have everything wired up properly and no, you don't need resistors the way you have it
wired. (Some would argue) The only thing that I can think of is that you aren't using the right audio wire and ground wire. Maybe
you got them mixed up by accident?
Try switching some of those audio wires about and see what you come up with.
If that doesn't work, and you have a voltmeter, see if you're getting power out of the TIP. The next thing I'd try is just using one
LED in the circuit (with a resistor) and see what you come up with.
I made a video to try and help everyone out. It might be useful.
neonix says: Mar 2, 2010. 10:35 PM REPLY
Well, I tried one LED with two batteries and still nothing. As for the audio wires, I had assumed that the copper was always
grounding. I tore open the wire to reveal the solder points so I'd know exactly which wires were what, and it turns out I was
right, so I had the wires connected properly.
I've tried three different audio jack/cables, two different TIPs, and several LEDs. I tested the single LED on my two-battery
assembly without the TIP and it lit up nicely. And after all this, I'm completely baffled.
eightnine says: Mar 3, 2010. 9:08 AM REPLY
Have you tried a different audio source? Like, try using a PC audio or maybe a different PC audio or a cd player or stereo
or something? I've done this circuit about ten times now for gifts for people and if you follow the video... I really can't
explain what else it could possibly be. :(
neonix says: Mar 3, 2010. 10:08 AM REPLY
I know it seems ridiculous lol. I tried my iPod, my PC directly from the sound card port, and even on my sound system
with the amp at full blast - nothing. Maybe I'll go get a breadboard and try it out in a more organized way. Then I can
move things around and troubleshoot more easily.
motadacruz says: Mar 3, 2010. 2:04 AM REPLY
Same here dude, baffled.
Just typing some checks here just in case:
- Is the PC master volume on 100% ? (Not the speakers itself, but the PC master volume)
- There is a guy with comments on this page that tried 1 PC and nothing happend, tried a different PC and it worked like a
charm. Problems with a crappy soundcard or something. Can you maybe try a different PC ?
Hope we can figure it out for you dude!
Spurr says: Mar 1, 2010. 11:04 PM REPLY
sounds to me like you burnt out the LED's (doesn't make sense i now)
try again but with an extra light, that is what i am going to do and i seem to have the same problem
thestyrofoampeanut says: Mar 1, 2010. 7:40 PM REPLY
a lot of audio cables have cotton woven in the wires
try pulling it out if there is any
make sure you make a good connection
thats just my guess hope it helps
moleyjoel says: Apr 30, 2010. 5:26 PM REPLY
would this still work if i replaced the audio-in cable with a microphone?
so that i can still hear the music through my speakers, however would the led's still light in time with the music?
silverslik1 says: Apr 29, 2010. 11:30 AM REPLY
Anyone know why the transistor is giving me a huge variable resistance and making my LED's very dim and not bright? I'm using a tip31C
Any help would be very much appreciated!
Mehheh77 says: Mar 10, 2010. 7:27 PM REPLY
Nicely done! I have lights like this wired along the walls in my room. I used two different transistors so each side would react differently as the music
millercl says: Apr 28, 2010. 10:48 PM REPLY
i was wondering what kind of transistors you used because i am going to make spkeaker boxes that is going to have led in it with a Plexiglas front that is
going to blink to the music, and would like the leds to blink differently in the boxes
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