Sync LEDs to Music





Introduction: Sync LEDs to Music


Here's a link to the wiring schematic that was removed

In this Instructable, I'll show you how to sync LEDs to music. I know this have been done before multiple times but this time I'll try to do it as clear and easy as possible. My camera is bad so please bare with me.

I've also made a video tutorial!

Step 1: What You Need

*This is what you need to make 1 channel. Double the quantity of this part if you want stereo.

9 volt battery
9 volt battery clip
*TIP31 (Or other NPN transistor)
*2 LEDs
*220 ohm resistor
audio cable or old headphones


If you have a breadboard you only need:
a knife or scissors
(optional) 3 alligator clips

If you want to make it permanent you'll need:
Soldering iron and solder
on/off switch
(optional) project enclosure

Step 2: Assembly

Everything will be done step for step in the pictures below as well.

1 Making it with a breadboard:

Start with connecting the 9v battery to the bus lane. Then put the TIP31 vertically somewhere near that bus lane.
Hook up the cathode (shorter lead) of the first LED to the collector (middle) pin of the transistor. Then connect the cathode of the secound LED to the anode of the first. The secound LED's cathode goes via 220 ohm resistor to positive voltage.
Connect the emitter of the TIP31 to ground on the bus lane.
Connect an alligator clip to a jumper wire and connect that jumper to the base of the transistor.
The other end of the alligator clip goes to left or right channel in the audio cable.
Connect another alligator clip to a jumper wire and hook it up to ground.
The other end goes to the power in the audio jack, there might be several power cables inside, any of them will do.
Copy everything if you want two channels.

2 Making it permanent (Both channels)

Solder both resistors to the positive end of the battery clip.
Solder 3 wires to the negative end of the battery clip.
Solder the anode (Longer lead) of one LED to the cathode of the other one.
Repeat above step.
Then solder the anode of the 2nd LEDs to the resistors
Solder two of the cables to ground to the emitter pins of the transistors.
The collector pins are soldered to the cathode of the two LEDs
The base pins are soldered to respectively the right and left channels in the audio cable.
The third cable to ground goes to the power cable in the audio cable.
If you want a switch solder the positive voltage to pin 1 on the switch and the
continiuing cable on the secound pin.

Step 3: And How Does It Look?

Well there is only one answer to that!



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    I did this project exactly
    I couldn't get anything from a phone or a mp 4 but got it with my audio mixer that sets out 20v
    After about 10 secs the wires at the battery started melting
    Is it because the mixer has too much power ?
    If so what do i do???????

    I have not tried this yet, but will be receiving my Bachelors in Electronic Engineering this weekend. From what I've gathered, you didn't "do this project exactly." If the wires melted, then YES, you have given too much power through the mixer, which probably has destroyed some (if not all) of the components used. The idea proposed is not the best way to produce the effect, but I have tested it virtually, and it does work with a .5V output (say from an MP3 player on max volume).

    im a newbie, i tried this circuit, and its doing fine, but when i use Y-splitter to hear the sound, LED became dim.. any suggention for a newbie.. thanks help help help

    can i use 12v 5amps battery to make this project with 4 leds (3v) and TIP 31c transistor.


    Please reply fast.

    Hi Guys, Can anyone help me with this little project. I made this work on 3.5 audio jack but I wanted to replace audio source to mic. Is this possible? can anyone send me a working photo/video of this schematics ( Please be advised that I have no electronic background. I learn from what I saw on youtube :D cheers. TIA


    hi made this circuit like this project i used 4 led but the circuit doesnt work like stereo...can u help me about that?

    Hello guys i want to make my 12v led strip flash to music so if you could please confirm if it would work i would make and test it but i have ordered the parts which will take 2-3 weeks to come and i don't want to waste any parts i also want it to be stereo
    here is the diagram

    Main idea taken from:

    Nobody cares. And I suspect that wasn't the very first time someone made sound reactive lights. Again, nobody but you should care.