Sync LED to Music




This is a very basic circuit for syncing LED's to music.

There are several issues:

1. You do not need a 9volt power source, I have used 3volts and it worked

2. Depending on your speakers system setup you will have turn the volume up very loud
       - I have connected this to a Latte Ipearl mp3 player, the volume (0-32) had to be a 26    to  get the LED to start to blink.

3. Make a amplifier to correct problems with volume having to be very loud.

4. I could not get this work using headphones; it did not work because I could not get the enamel of the headphone wires, so I cut open the headphone jack and connected my own wires.

5. If you have an equalizer you can adjust the different frequencies to and the LED will blink accordingly.

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Step 1: Connect and Enjoy.

Materials: (scavenge electronics if you can)

Power source - 3volts to 9volts should work
Resistor          -  220ohm, though I have used 150k and it worked
TIP31 NPN Transistor  (Negative Positive Negative)


1. Connect the resistor to the power and the positive side of the LED
2. Connect the negative (look for the flat side) of the LED to the center pin (collector) of the transistor
3. Connect the positive side of your audio signal to BASE on the transistor
4. Connect the negative side of your audio signal the Emitter of the transistor
5. Connect the negative side of your power source Emitter of the transistor
6. Turn on your power source, turn on you audio, turn up the volume and experiment with a equalizer (VLC player has one built in to the software and it is free)

Step 2: Placement of TIP31 NPN

you may use a bread board or simply soldier each step

Step 3: Be Positive

Connect positive pin of LED to center pin of transistor.

Step 4: 220ohm Resistor

connect one end of  resistor to negative pin of LED connect other end of resistor to power.

Step 5: You're Grounded

Connect emitter (E) pin to ground

*ground is the negative of your power source or battery

Step 6:

Connect base (B) pin of transistor to positive line in audio.

Step 7: You're Grounded Again

Negative from audio to ground on circuit

Step 8: And Again

Negative of battery/power source

Step 9: Something Positive

connect positive of battery/power source to circuit.

always good to connect power last so not as to fry anything.

Step 10: View From a Different Angle

Step 11: Enjoy

I made a few changes before making the video, in the video the blue wire is negative from audio and the white/blue wire is positive from video



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23 Discussions


2 years ago

Can I use a small npn transistor?


3 years ago

Can I do this using speaker wire instead of the line-in jack? I'm making a bluetooth boombox and I think this would be a nice addition.

Just so you know NPN does not mean "negative positive negative" but specifies the type of silicon used to make the transistor.


5 years ago on Introduction

hi i tried this with 4 led strips but each strip has 24 leds on each so im guessing this circuit isnt powerful enough but i noticed the leds dont have resistors built in nor have i put 1 in so could this be the problem? cheers


6 years ago on Introduction

This is the best I have seen on how to wire the led to sync with music. I have tried it myself but cannot get it to work.


8 years ago on Introduction

Before anyone comments, I do not know anything about electronics. I do not know anything about circuitry.

This instructable is a remake of what of one

zatek made

3 replies

Reply 8 years ago on Introduction

i did this instructable. but something funny happens, when i plug it to my ipod it's works , but when i pluged to my laptop nothing brights... do you have any theory?
can you help me? :D

Thanks :D


Reply 8 years ago on Introduction

does it work on your laptop if you turn the volume up high?

The project works with mp3 players only with the volume up real high.

Here is my theory

There is something with audio signals and speakers called impedance (I think that is the correct term), which means the signal and the speaker need to match (this matching gets into a realm I do not understand). for example not all mp3 players will match 8ohm speakers. that is just my guess

It was suggested to me to place a resistor between the LED and the Collector or center pin.

an idea i did have and might try is put a omp amp (many listed on instructables) and run the output of the amp to this circuit that, my hypothesis is that with the op amp the listening volume could remain low but the signal to the LED circuit would be high enough to flash the LEDS. I'll put it together soon and let you know. here is the instructable i followed in making to the op amp


7 years ago on Introduction

How would you amplify the signal to the LED's? I have this setup for my home entertainment center and it works awesome at a moderately high volume, but I don't want to bother my neighbors next door, just because I want to see my LED's flash to Grand Turismo at 2:00AM.

And it would be awesome if I could adjust it, so when I blast the volume the LED's aren't just full blast all the time. Thanks

3 replies

Reply 7 years ago on Introduction

Yes, there are very simple amplifiers, I will send you a website. The amp I have made utilizes a LM386


Reply 7 years ago on Introduction

I'll probably work on that next weekend. What if I ran a variable resistor and two or three 9v batteries on the led's?

That might exceed the 12v rating on my LED's, but then I could add a 12v voltage regulator.


7 years ago on Introduction

atlast. thank you so much for your instruction.
i already finish my project..

dog digger

8 years ago on Introduction

This will work with any npn transistor. I just use a 3mm LED and a 3904 and it works great! thanks for this awesomely simple instructable!