In this Instructable I will be showing you how to create a light reactive LED system. In this clip, I used a single color LED strip, but you you can use a single LED, multiple LEDs wired together, single color or RGB LED strip, it just depends on what you are trying to build. The set up is fairly simple, the component list is fairly basic so if you are a tinkerer you should already have the majority of the materials laying around. If not, I will post links to the components I used so you can order parts and get to work! 

In the following link you will see the entire setup. Obviously you may arrange it anyway you would like, I just kept everything close and compact for the sake of an easy video. 


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Step 1: Components

Picture of Components
For this project you will need the following:

1) LED  ~$20 (with shipping) 
- For this project I used a solid blue LED strip which I purchased on amazon. These 5 meter SMD 5050 strips can run around $70 in retail stores so I though I would be taking a chance purchasing something priced under $20, but I was not disappointed in the least. I'm sure there are better quality lights out there, but if you plan on cutting these up and have no real game plan you wont feel any guilt putting these through the ringer.

2) Mini breadboard  $5

3) Arduino Uno  $30

4) Solid core wire  $2.50
- For anything involving breadboarding, do yourself a favor and stay away from any stranded wire. It will just end up getting frayed and hard to manage. Solid core is the way to go. I also like to choose at least two different colors for my wire to keep grounds and powers visibly separate. It makes troubleshooting and wiring easier in the long run when dealing with a lot of components.

5) USB A to B cable  $4
- This will be used to upload your Arduino LED code to the Arduino Uno board

6) Wire cutter/stripper $5
7) Parallax Sound Impact Sensor $10

8) Wall Adapter Power Supply - 9VDC 650mA $6

Total cost will be a bout $80 but keep in mind, all of these components are completely reusable. You can recycle them into a multitude of projects in the future so try not to worry about the cost. Think of it as building up your technical tool box :)
Matkezi15 days ago

Nice man :) However, is 9VDC 650mA really enough to power 5M LED strip. As I read through the net I come up with 12VDC 5-6A power supply is needed? Thanks :)

BryceN28 days ago

So to be honest, I cant entirely be bothered with learning the Arduino code, could someone copy and paste a code that will look sweet? Cheers (y)

ro8erts52 months ago

So I'm really new to electronics and I am attempting to do this with 1m tricolor LEDs from RadioShack. However my LEDs have 3 leads at the end to plug into my Arduino's ports. Also I can't see any noticeable reaction from my sensor, even when I replaced the strip with a single LED in the breadboard as was shown in the picture of the circuit. Any suggestions as to what might be going on?

schwaigor3 months ago

Great post man. I am no way educated at tech things, and I am wondering how this would work for what I have in mind. I originally was going to buy RGB light strips for the insides of my drums that pulse or strobe, etc. Seeing this thread though gave me a much better idea. How exactly does it work. For instance, could I program this to cause the light to activate every time I strike a drum?

schristie53 months ago

Great instructable. Easy to follow. I'm new to the whole arduino and coding . I made this with just a simple rgb led but only used the red led to follow along with your tutorial. How would you go about coding the other to outputs into the sketch.

Eventually I want to get it to fade between the colors while it reacts to sound.

kelkarapoorva5 months ago

This is expensive. Make one using simple OP-AMPs.

Only the thing is that you will have to give a sound input via an AUX cable to the circuit.

Try the circuit below...also put a 10K potentiometer before input of sound so that you can control the intensity of the LED strip.



Nice Schematic! An even cheaper approach would be to use a "TIP 31 Power Transistor"

This schematic uses TIP31. If you use it without the opamp circuitry, the response to the music woudnt be good. I have tried it that way also. And if you use only the transistor, it cannot handle LeD strips above 2-3 meters whereas this can handle about 3 amperes of current (5-8 meters). Also no heat sink required if used with the opamp circuit.

Sorry about my ignorant comment. It was late at night when I said that, and only briefly looked over the schematic without really paying attention to it. After reading your response, at first I was like "LEDS don't draw allot of current though." Then yesterday I was messing around with a circuit that I had made awhile ago on a bread board with about 20-30 LEDS all in parallel, and hooked it up to my DC power supply and set it to 12V. I then proceeded to see how they all looked lit up again, so I picked a really dub-steppy song that would work great for testing, and watched the mimi rave on my work station in the basement. I then noticed that every so often, the needle of the AMP reeding would jump up to half an amp depending on how the song sounded. (I thought to myself "Well this is odd") Shortly after I smelled that wonderful smell of burning carbon, so I cut the power and proceeded to see how hot the TIP 31 had gotten. Foolishly again, it was late at night and I wasn't thinking, so I received a slight burn on my finger, and then realized that I had the Infrared Thermometer on the table top next to me. So I took a reading and noticed that it came out to about 120 ℉ . After that I just slapped a heat sink onto it and took another reading, about 74℉ this time.

Basically all I'm saying is, yes an op-amp seems like it would be more efficient and wouldn't have to worry about the Transister burning up with/ without a Heat-Sink.

Thanks! Exactly what I wanted to ask, since the light response in video seems just a little bit late for me. This would solve that, right?

It looks lagging because of the video. When you make it and see it for real, its response will be instantaneous.
Actually the response just seems late in the video. But in actual it is instantaneous. Both are instantaneous only only they appear delayed in the video.
GraziCNU (author)  kelkarapoorva5 months ago

Thanks for the alternate method!

You are most certainly welcome.
notjohn133 months ago
Is it possible to not use a breadboard in this project
megadarkwood4 months ago

would it be possible to do this but have a 3.5mm input and output? so you can use headphones?

jkalna224 months ago

very misleading. You show a rgb led strip in your main picture but then fail to explain how to set it up. You explained the concept well though.

Doreena12114 months ago

Recommend to buy High Quality and Cheap led strip from above store.

Anth0ny5 months ago

How can you let the led strip work because when i made it the led's doesn't work. The scematic is for 1 led and not for a led strip who needs 12 volt. Can somebody help me with this problem ??

Raitis Anth0ny4 months ago

There are plenty of tutorials and probably instructables that describe hooking up led strips to Arduino. Simply put: use a transistor as a switch for the LED strip.

i need that kind of answer also :S

nr0025415 months ago


I am having problems. When i connect the led ground to the output of the sensor this works fine but when the arduino is connected the leds just stay on. Do you reckon i have a dodgy arduino or is there something wrong in the code others have had issues with?

theViTALiTY5 months ago

Wait i dont get it, how does the LED strip get enough power since its 12V, and we are powering arduino with only 9V. Can this thing be done without arduino, just a plain connection from parallax to led strip?

mgarland25 months ago

Super easy to follow, GREAT detailed instructions and videos, a solid project for a beginner. Thanks!

dorkpirate7 months ago
neat instructable. can imagine this in a car
GraziCNU (author)  dorkpirate7 months ago

Haha that would be cool, I just stuck them up behind my computer for the time being.

sic6sic GraziCNU5 months ago
ive got something like this in my trucks cab. what id like to do is to be able to separate the frequencies so that hihats trip one set of lights, mids trip another, and bass trips a third. im just not knowledgeable enough to build a circuit (im not even sure what type) that can be powered from the 12v battery and utilizes either auxiliary or in-line I/O.
GranpaO44 sic6sic5 months ago

Sounds like your looking for a Color Organ Kit. There are several on this web site. Just type "Color Organ" in the search bar.

sic6sic GranpaO445 months ago
as useful as those search results have been, they still arent quite what im looking for. essentially, id like to make a set of filters (low-pass, mid-pass, and high-pass) to both separate the audio, and drive the LEDs. though, i discovered that i need a decent set of resistors to prevent the LEDs from being fried at a higher volume.
rharrison25 months ago

How many LED strips can you control with one sounds impact sensor?

areye0215 months ago


I was wondering how you connect the RGB Led Strip to the arduino. I saw your connection diagram but thats showing a single LED. Any ideas?

Thanks for posting your work.

GraziCNU (author)  areye0215 months ago

I have not personally tested this set up but it is relatively similar to what I have made here.

GraziCNU (author) 7 months ago

Just as a side note, an alternative to this is just powering the sound impact sensor and LED and connecting the ground of the LED to the SIG line of the sensor. That's a bare bones approach, but using the Arduino will set you up for more variation if you choose to get creative. You could have the lights pulse on when sound is detected as opposed to pulsing off by changing the digitalWrite() power value, you could use an RGB LED to fade colors and pulse the lights. Use this project as a jumping point for your creativity!

GraziCNU (author)  GraziCNU7 months ago

Just don't get TOO creative.