Music LED Light Box

Picture of 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 website or  YouTube channel for more information and songs.

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Step 1: Materials & Tools

Picture of 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 whole 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)
- Pen

Ones you've got this stuff you're ready to begin!

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.

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. Get 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.

Step 4: Building the box

Picture of 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.

CircuitThe 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.

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 right spot.

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.

That's it!!
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.

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paquiton964 months ago

Leds are not lighting because the jack voltage isnt enough, how can i boost it?

An amplifier (VERY low db) can help boost the audio signal. Also, a small DC voltage (like a <1V battery) in series will help turn on the lights, but may cause the change in brightness vary less. Try using an audio device with a higher output.

ThaXified4 months ago

Did you Guys see my LEDS already?


mmehzin3 months ago

how do i hear the music if we put audio jack in laptop?

bostaba mmehzin1 month ago

Search the web for an "Audio Splitter". That's what is needed to split the audio.

en_rov mmehzin2 months ago

You could wire another plug in parallel for AUX out

huyvu892 months ago

Can anyone tell me how can i hear the music when i already plug the jack into computer? please explain.

bostaba huyvu891 month ago

You just need an audio splitter. One cable plugs into the lights, the other plugs into the speakers.

bswt2 months ago

i have a setup where i have 400leds wired in set of 4 so, 100 a group, could the tip31 switch them? or the better question would be, whats the max switching current (amps) tip31? if is more than 4-5amps than I'm fine. well i do have 3 here with me, so if it works than ill report it here.

bswt bswt2 months ago

after doing some testing i've found that one tip31 can handle 100leds any more and the tip31 cant open well enough

huyvu89 bswt2 months ago

how can we hear the music if the already plug the jack to the input sound?

rbeck_v huyvu891 month ago

use a 3.5mm audio splitter, plug the splitter into the music source, plug speakers/headphones into one side and the led cube into the other

Nanu_hb2 months ago
Ani equivalent transistor for tip31...

BD243C that is what i use :) works just fine

Nanu_hb2 months ago
Any equivalent transistor for tip35
Jacob Dorr2 months ago

Your brothers music funks man, thanks for referring to his YouTube channel!! Is there a link to the cube in action? For some reason I can't see the video above...

eimua3 months ago

Can i use tip35c for this project?

eimua3 months ago

Can I use TIP35c in this project?? Please answer.

jthunder29 months ago
Anyone try this with rgb color changing led's? I'm going to try it but I'm not really sure how well it'll work out.
Update in case it's helpful. COLOR CHANGING LED'S ARE AWESOME IN THIS.
How did you do that?
I purchased RGB flashing led's like these ( I also changed things up a bit. I used a laptop power supply cable for power. It gave me 18 volts. I ran four parallel chains of led's on two circuits with separate transistors. This gave me a total of 24 led's. I used both left and right channels so when listening to a song that has different parts playing on each speaker each half of the lighting would do its own thing. It looks really awesome. I also painted the back of the back piece of glass white, so that it would reflect more light forward. Oh, and I added a resistor in series with each string of led's. I thought about making an instructable for it but didn't know if that was a violation since it was just an improvement on someone else's design.

You should be fine. Just ask the orignal guy and tell him your idea, I'm sure he'd be happy to let you do this.
Plus I'd love to see how you did this :)

Awesome, can you please share the circuit?
Yeah. I'll draw it up and post a link.

What resistor did you use in your build? Also what was the amperage of the laptop power supply that you used?

This is the schematic for what I did. If you use a computer power supply cable, you will have lots of current to spare. In theory, you could put a few hundred led's into an array of 6 series led's in many parallel chains. Does that make sense?
sweetie037 months ago
Hi, awesome work guys... i just started learning these things and dis is quite fun ..can i use a bc547 npn transistor in place of tpi31 ?

try it and see what happens. They are all NPN transistors. Just make sure you plug it in correctly.

tamlani4 months ago

hey plz help me out. i am using 5m led flex roll with 12v adapter. plz guide me how many transmitter would i need as i am using one TIP31C but it doesn't work...

it's transistor not transmitter. And one tip31C is all you need. However if you're 5m LED flex roll requires more than 12V to light up then you're going to see no light. Also keep in mind that the volume on your stereo must be high enough for the transistor to read a voltage coming in.

I've having some troubles with this. When I connect my LED to the farthest left pin of the TIP31 I get some constant light but when I connect it to the middle pin nothing happens. I'm using the headphone part from old apple earbuds if that makes a difference.
I'm having the same issue. Constant light on either side pin and no light on the middle pin. I thought maybe it was the transistor, but I changed it out for a new TIP31 with the same results. My schematic is slightly different. Any thoughts on why this might be happening?
tamlani dseter4 months ago

heyy did u find any thng good relating to your problem??

i am having the same problem... i am using 5m led flex roll and 1 transmitter TIP31C and a 12v power suply...plz help me out if u know how to deal with that. thanks

are u sure your looking at the front of the tip 31 when connecting the wires. you might have the right confused with the left causing problems.
xangel5 months ago

Hello! I am new here and.... I have a question about this project: What should I do to make it work with light bulbs at 220V ? :D
Thank you!

MarioNL xangel5 months ago

Search "Relay" on google. I wouldn't do it as a beginner though, because you will be working with high voltages. Try some smaller projects first.

csshandy5 months ago

if you use lets say for example a car stereo and try and connect it to a high or low input of one of the channels it can cause some problems because the stereo is using the 12 volt car battery and the tip31 is aswell it can create a short circuit because the sound out of a stereo is A.C meaning the wire on the ground side can shift from low to high causing a short circuit the only way I can think of around this is adding a 1k resistor between the power for the tip31 so that it stops this however haven't tested it, this is my understanding of it so if anyone has anymore input on this feel free to give advice I will test this theory out tomorrow and post back.

bitone9 months ago
I have put 3 leds with a 9v adapter, and when i plug it into my pc i have to turn my volume to 200% to get around 40% of led's brightness. LED's shine bright when tip31 is not present. Any help? (I've checked every single conection,everything appears to be in order but it wont light up bright)
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