Introduction: Build Your Own LTMT

Picture of Build Your Own LTMT

No it's not a Lettuce, Tomato, Mutton, & Turkey Sandwich. It's a Light's To Music Tin.

So what does this really do? It flashes a LED to the high volumes of music. It is a EXTREMELY simplified version of the other light to music or dancing lights circuits that exist. Special thanks to: Awang8 for letting me that I didn't describe what this did.

This is how to build one If anything doesn't make sense please let me know. I'm try to keep my instructables so everybody can understand them. One down side of this is on an iPod the volume has to turned all the way up for it to work. So it's the best for listening to music through a pair of speakers.

If You Have Any Questions, Comments & Suggestions Please Post Them!

Step 1: Stuff You Need:

Picture of Stuff You Need:

What you need to Get the Job Done


1x 5mm LED Any Color
1x 2n2222 NPN Transistor or other general switching transistor
1x 220 Ohm resistor (Red, Red, Brown)
2x 3.5mm Female Audio Jack
1x AA battery holder
1x Mint Tin (Altoids, Eclipse, any thing that will hold 2 AA battery's)

Tools: (No Pictures)

Soldering iron & Solder
Drill Bits
Wire strippers/Wire cutters

Not Needed but Helpful Tools:

Round Metal File
Helping Hand

Step 2: Prepare the Audio Jacks

Picture of Prepare the Audio Jacks

Your Audio Jacks Don't need you be connected like the ones below as long as you know where the ground and the left & right channel are then they'll work. One thing that is neat about this setup is that is doesn't mater what jack you plug your input & output into.

1) Solder a wire between the left audio channels
2) Solder a wire between the right audio channels
3) Solder a wire between the grounds
4) Solder a wire that is about 2-3 in long* to the ground on the audio jack
5) Solder a another wire that is about 2-3 in long* to the right audio channel on the audio jack

*This length depends on where the audio jacks are in relation to the led transistor thing.

Step 3: Make the Circut, Guts, Main Thing. What Ever You Want to Call It

Picture of Make the Circut, Guts, Main Thing. What Ever You Want to Call It

If you have a similar transistor to mine then when the flat part is facing you the leads from left to right is Emitter(-) Base Collector(+)
Throughout this instructable the flat part of the transistor is pointed down so the leads would be
Collector(+) Base Emitter(-)

1) Spread the leads on the transistor carefully & split the led leads like in the 2nd picture
2) Solder the Negative end of the led to the Collector(+) of the transistor.
3) Solder the 330 Ohm resistor between the Base and the Emitter(-)
4) Trim the leads of the resistor

Step 4: Connect Circuit, Audio Jacks, and Battery Holder

Picture of Connect Circuit, Audio Jacks, and Battery Holder

I don't have much to say about this, except make sure that the audio signal is going to the Base of the transistor. Once this is done test it to make sure it works.

1) Solder the right audio signal to the base of the transistor
2) Solder the audio ground to the Emitter(-) of the transistor
3) Solder the negative battery line to the base of the transistor
4) Solder the postive battery line to the positive lead of the Led

Step 5: Prepare the Tin

Picture of Prepare the Tin

When doing this gloves might be a good idea, but as you can see i didn't where mine. I deiced to use the dot of the i For the led. You just make a small dent for the drill bit and drill the holes. See the pictures for more info.

Step 6: Stuff the Tin

Picture of Stuff the Tin

This is kind of self explanatory put the led where it goes and the Audio jacks where they go. Then fit the battery holder in.

Step 7: Your Done

Picture of Your Done

It's Done Now Go Try It Out

Step 8: Troubleshooting & More Ideas


Try new Batteries
Make sure he led is in correctly
Make sure there is no shorts
Check your components
Check the volume

More Ideas (Taking it Further):

Add a Stereo Potentiometer between the audio jacks to limit volume output so it's quieter through ear buds
Add more Led's so they flash at different volumes
Make it more sensitive
Make it vibrate
Add a Amplifier so volume doesn't have to be so loud for it to work


TacticalTrumpet (author)2012-03-17

What is this?
It looks cool but I want to know for sure what it does.

tomtortoise (author)2010-07-16

yo can i make this with one headphone jack, replace the light with a speaker, and use a nine volt battery to make an amplifier?

vadipp (author)tomtortoise2012-02-05

Yes, but it would be a _very_ bad quality one.

qwerty156 (author)tomtortoise2011-06-05

Could anyone please anwser this?
It would be very help full

darockerj (author)2011-08-14

is there a way to have the led be on the inside of the tin? i wanted to put an image on top and have it shine through at a certain point.

sephiroth67 (author)2011-07-05

That all seems to fit pretty perfectly, well done!

LuciusDeRais (author)2010-05-15

I have tried with this ( that i have taken at shool, but the uotput tension from mine iPod is not wnough. Can you help me?

Thanks and sorry for my bad English. (I'm Italian)

TZENOV(new) (author)2009-11-20

It works man thanks for the good explanation of things! In fact I use 2 LEDs and it works well!;)

bounty1012 (author)2009-03-29

Lol how would you fit all that on a sandwich?

computergeek (author)bounty10122009-03-29

Carefully. :-D

bounty1012 (author)computergeek2009-03-29


artcobain (author)2009-03-09

can i make it multiple leds?

computergeek (author)artcobain2009-03-09

Yes, just wire the LED's in parallel. If you use a 9v battery you need a resistor between the positive end of the LED's and the positive end of the battery. (The resistor is need is needed even if you only have one led)

artcobain (author)computergeek2009-03-09

i will show you my project when im done

computergeek (author)artcobain2009-03-09


computergeek (author)artcobain2009-03-28

That's Cool!

artcobain (author)computergeek2009-03-29


artcobain (author)computergeek2009-03-09

thanks for that, i will dhow my project when i'm done

awang8 (author)2008-12-18

Ok, so I finally stopped being embarassed about asking this question... What does a LTMT even do?

computergeek (author)awang82008-12-18

I kind of designed it to be a very simplified form of the other Lights to music or dancing lights circuits on this site and the web. It makes a great beginning electronics project. Don't be embarrassed I didn't really explain what it does. Thanks for catching that.

duck-lemon (author)2008-12-06

Are you by any chance from NZ or AU because if you were from America or Britan you would most likely be using an altoids tin given that is a commonly used housing in this 'ere websiteamatron, just saying.

computergeek (author)duck-lemon2008-12-07

I'm in the US. I used this because I only had 1 Altoids (Myntz) tin and I wanted to save it for when I needed the extra room.

Arbitror (author)2008-11-27

Dont you think thats an awfully big tin case thing for that little electronics?

computergeek (author)Arbitror2008-11-27

Believe it or not there's not much room in it with the batteries in.

awang8 (author)computergeek2008-12-07

Yeah, for my Eclipse Torch (no Instructable) one I has to use AAAs cause I kinda got carried away putting fancy switches, massive LEDs ect. I could have stuffed AAs in there if I used just a plain old LED and a boring push-switch.

awang8 (author)2008-12-04

Do you need a 220ohm resistor or a 330ohm? It says 330ohm in the parts but in the photo it says 220ohm.

computergeek (author)awang82008-12-04

It's 220 ohm. It doesn't really matter what you use. If you have a breadboard i would suggest trying different resistors out. Thanks for catching that.

tomasys (author)2008-12-01

nice one... but there should be a way to make it work without having to max the volume

computergeek (author)tomasys2008-12-01

Thanks You might be able to run it through something like an op-amp. Another thing that might work is to put a resistor between the collector and base, but I didn't test it.

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