In response to music. Use a LED light removed from a pen, lighter or similiar device and a few other components to build it. No soldering involved. This is a simplified version of the blinking LEDs instructable posted here earlier. I shall try to elaborately describe each step so that a person with little experience can successfully build one.

The emphasis shall be on the methods of wiring and testing a simple circuit. The product of this instructable is not the blinking light you build - it is the knowledge that you gain as you build this extremely simple circuit, with materials that are commonly available, with simple tools and very little specialised skills.

Step 1: Take the Lamp Apart

Parts: Now that many gadgets come with an LED torch (flashlight) built in, it's easy to just buy one and take apart for the batteries and LED. You have to liberate the torch part from the pen, cigarette lighter or keychain or whatever. You should get three button cells, one LED and some sort of switch for completing the circuit.

The picture shows a pen with built in LED flashlight.
hey, can you please make a material list??? so i can see what i need to buy
would 5mm LED lights work for that?
ANY sort of LEDs would work. 
k Thanks!
i have tip41c, can i make with it?
Would this work better or worse if you used a small 9v amp before the transmitter?
oops sorry I meant transistor, did you spot it? ;P
hey big question if you connect the earphone jack on any music devise the music should mute and only listen on the earphones, right?, why in the video the music is still playing and the earphone jack is in the music devise in this case a pc?
<a rel="nofollow" href="http://www.infobarrel.com/How_to_make_LED%27s_Dance_to_your_Music">If anyone wants another link that explains the wiring more.</a>If anyone wants another link that explains the wiring more. <br/>
You got a lot of old stuff. Nice instructable! Thanks. If you could put a schematic draft, that would be even better.
where in the world did you get all those transistors?!?!?!?
awesome job dude...i tried the flashing lights thingy with my iPod and the lights worked!!!
hmmmm...you think the transistor might be able to amplify sound also?like from an iPod to a Speaker?
nice schematic! i love the hand drawn ones... so scrappy.
me too, but only those drawn by hand and scanned or drawn on computer, but with a kind of anti alias, like blur...
Great! Thanks.
oh i didnt used a resistor does that matters?
Depends on the LED voltage requirement, if you send through 4.5v to a 3v LED it will burn out relatively fast compared to if the voltage was regulated through a resistor.
Hey man thats sweet but my led doesnt go too brighty i dunno y does i need an amp to make it verry bright?
Very exaustive explanation....but...any idea about how it works? ; )<br/><a rel="nofollow" href="http://www.youtube.com/watch?v=cQaF4bmuojo">http://www.youtube.com/watch?v=cQaF4bmuojo</a><br/>
Question, Could you just use a simple relay instead of all this crap? :)
the transistor is bascily the same as a relay, just smaller and quieter.
Oh.. I knew that.
when I saw you picture with the transistor in it, I noticed that it is an amplifing transistor, that is great for this project because it is way more sensitive to voltage over the collector.
LOL did you use a scanner to get those pics ?!!? Awesome !
your avi file didn't work for me (I'm using quicktime)
You aren't missing much. The movie just shows the blinking LEDs and has some music. Next time, I am going to put the movie up on www.blip.tv
Hey nice job. I am gonna make this but i am not gonna use the resister do i just replace it with a wire?
Just leave it out, it might work. If it doesn't, you can try leaving the earphone in circuit (in place of the resistor).
nice idea, but I was very impressed with the high quality, really close pics
w00t mines works! but my transistor sucks so it only works well with my rbg leds but atleast it works! thanks A TON for this instructable very clear and simple!
If you have a large stereo you can just hook the lights straight up to the speaker wires.
Awesome! Simple and nice for starters ;)
Any idea on how many of these I could wire to an amplified signal before the effect lessens noticeably? Or would it make more sense to wire multiple leds to one transistor, and then fiddle with the resistor? I'm trying to figure out the simplest way to have 4-6 sound-blinky leds on the front of my guitar amp.
Awesome, i did this and it worked great! - i used a TIP31 NPN Transistor - Radio Shack.
Maybe i could use a mic to make it more portable.
No. The signal from a mic is not large enough.
I know but if it were attached to somthing like this.........<br/><br/><a rel="nofollow" href="http://www.amazon.com/SPY-EAR/dp/B0006GKFZ8">http://www.amazon.com/SPY-EAR/dp/B0006GKFZ8</a> (Its a little toy that is supposed to amplify sounds amd uses a headphone jack)<br/>
I f you don't know how many ohms your resistor is go to <a rel="nofollow" href="http://www.the12volt.com/resistors/resistors.asp">http://www.the12volt.com/resistors/resistors.asp</a><br/>
I can't describe how much this helped me!!!!!!!!!!! I have been wanting to do this for soooooooooooooooooooooooooooo long. Very easy to follow. All in all A great instructable!!
This is super nice. I like it a lot. It's much simpler than the circuit I found: How loud must the input be? I'd like to make one that's connected right to a microphone on a lapel.
The input has to be loud enough to be heard in a speaker or headphone. It cannot work directly from a microphone. The stages of amplification needed to light an LED in response to the sound picked up by a mic would make that a very complicated project, and I generally tend to lose interest and give up half to a quarter of the way through such giant projects. I do not have a digital camera, so I use the scanner to take pictures. The circuit is arranged on the scanner's glass plate, and a piece of clean white paper placed over for the background. Generally scanning at 400 to 600 dpi and then reducing the size gives the best results.
neelandan, you're so amazing.
I also like the way you took pictures of the bits and pieces. How'd you give it such a clean look?
I'm very amateur in electronics, but to solve the no sound issue - couldn't you take an input and wire that parallel to the transistor? That way the input signal gets split in duplicates, and then you can plug your normal speakers into the input you just made, and the other path would drive the LED? I'm sure something about that is flawed though, but hey, it's a start? :)
why you dont put blocking capacitor?
might be use full in a auto wah circuit or other envelope filter.
Dude, I've been trying to do this for ages with my USB Christmas Tree, but all of my transistors kept blowing. I guess I should look up the data sheets before blowing them.<br/><br/>By the way, &quot;MAD PROPS&quot; for using HD cables as wiring. If you check out my Beating Heart T-shirt instructable, you'll see they're my favorite =)<br/>

About This Instructable




Bio: Hi. I'm Chandra Sekhar, and I live at the southern tip of the Indian subcontinent. I'm interested in building small one-off circuits around ... More »
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