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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.
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Signing UpStep 1Materials & Tools
In this instructable I'll explain how I made it, a very simple way.
Materials
- 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.
Tools
- 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!
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Thanks
I want to make this for my systems class :)
I was just wondering what lets the cube sense the beats in the music to flash? Cause theirs no programming involved.....?
Also i was looking at making one 2 times bigger so 12 leds and like 30cm long, how would i go about this??/
I was wondering if there is any way to boost the signal. I have my computer volume at 75% before it begins to light up in a desired manner. At 75%, the music is too loud to listen to. Any ideas?
and one more question will this work if it is plugged into the sub woofer output of my amp in my car?
I mean Using Capacitor (as Band Pass )
I encourage you to use the wiring diagram attached to this comment. If you have any questions, please address them to this comment, because the comment conversation below has old versions of the diagram that are incorrect.
You can download the diagram in high resolution here.
By the way, you can save a lot of money (and also learn an overwhelming amount about electronics) by ordering parts from DigiKey.com. Corporations order high quantities of parts from there so prices are low, and shipping is cheap.
I'm glad you're trying this out, good luck to you.
nice tut, but can I power it with my PC too? I mean a 4-pin Molex.
Can I use more than 4 LEDs without using another source?
Sorry for my bad English
Greets
USB also is a good idea!
Can I use 9 or 12 red LEDs?
LED: 2.25V, 20mA
I want to put them behind my LCD and split the 3.5 jack plug (left, right subwoofer) so that the side is blinking where the sound comes from.
Is that possible? Do I need three electric circuits?
"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"
Is that why you produced a circuit designed to destroy components and not be repeatable? This is a bad circuit:-
1) No current limiting resistors on the LEDs this will destroy them over time.
2) No current limiting resistor in the base of the transistor, and no protection against the reverse voltage on the base, this will destroy it under certain conditions.
3) It requires at least 0.7V peak output audio before anything happens.
4) Depending on the forward voltage drop of the LEDs used there probably will not be enough voltage from 12V to turn them fully on, use one less LED.
5) This will cause the audio level to clip at 0.7V causing severe distortion to the music. Mind you you probably don't notice that with that sort of music.
Apart from that it's grate. (sci)
I have a few elaborations to make and some questions to ask.
1) Resistance needed for LED arrays can be calculated HERE. You simply have to purchase however many resistors the calculator tells you to. This is necessary because the power supply won't match up exactly with the voltage needed by the LEDs. Resistors offer a way to get the voltage to exactly what the LEDs need, and in this way you can prolong the life of your LEDs.
2) Why does the base of the transistor need a resistor? Also, in another comment, somebody mentioned using a voltage follower amplifier to protect the reverse voltage on the base. Would that be a good solution?
3) This is good to note, but not very important - the box obviously works pretty well, judging by the video he posted.
4) Again, his video proves otherwise; the LEDs look great.
5) The audio signal is not output to speakers through the box - you won't notice distortion because the box has no effect on what you hear.
Thanks for raising all of these points.
2) - To limit the current to a value that is safe for the transistor and the thing supplying it. Yes with a voltage follower you don't need a base resistor because of the negative feed back given by the emitter load limits emitter base voltage and hence base current. However it will not protect against negative base voltage. You are dependent of the transistor to withstand that and some transistors might be destroyed by it. In the case of this transistor anything greater than 5V will damage it.
3) It means that on some system you will not get enough voltage to drive it. However as you say his exact setup produced enough, will other peoples?
4) This is true only if you use LEDs with a forward voltage of less than 3V. Many coloured LEDs have a much bigger voltage than this.
5) From my reading of the circuit the box was placed across the speakers sending the same signal to both the box and the speakers. However if this is an independent amplifier output then no it won't distort, but how do you listen to the sound.
2) If this is true, that means this Instructable, if followed exactly, will give you a circuit that destroys its transistor after some amount of time. I would assume that the user who wrote this Instructable has tested his circuit and would have fixed the tutorial if it didn't work. Also, if you use a resistor big enough to limit the 12v input to the 5v the transistor can handle, you would lose a lot of power and the LEDs wouldn't be as bright. I'm interested in the voltage follower amplifier concept though; how could I add one into the circuit in my wiring diagram?
3) You're right. I was just assuming that if a person following this tutorial was knowledgeable enough to change the setup, they would know how to modify the number of LEDs used.
4) That's true, but again I assumed that the builder would be knowledgeable enough to compensate for the changed voltages.
5) In the wiring diagram I attached, I have an audio splitting cable: it goes from one male 3.5mm plug to two female 3.5mm jacks. One jack will feed the speakers and the other will feed the LED box.
Thanks for the reply!
1) The collector and emitter of the transistor are swapped over. You should have the emitter to the -ve of the battery and the collector to the resistors.
2) you should have a resistor 1K but not critical between the channel input and the base of the transistor.
If you use a splitter then there will be some distortion because the signal is just split not isolated. That means if you short one signal from the splitter the other gets cut down as well. The 1K resistor reduces the amount of clipping the audio signal gets but it doesn't get rid of it altogether.
The problem with a voltage follower arrangement is that you need to have a much higher audio output before any of the LEDs start to light up. In this case it would have to be 3.5V, where as with the amplifier arrangement we have here this starts to turn on the LEDs at 0.7V.
I added the resistor in.
I think that is unavoidable without overly complicating this circuit.
Thanks for all your help, Mike!
I have attached an updated wiring diagram if anybody is interested.