Lights that get brighter to music

I have a stereo in my car. I want to hook up lights to my stereo so when it gets louder the lights get brighter. I know this can be done because i did it years ago, however I don't know what lights to use or if i just hooked it directly up to the speaker wire. Could somebody tell me what kind of lights to use, and how to hook them up please?

i dont know how to make one but the autozone around here has em for sell just if you wanted to buy one.

Do you know what they are called or what i should look for? I went to an autozone yesterday with no luck.

no im sure what they are called the one i had what looked like a metal wire running through it detecting vibration and got brighter as music got louder.. i also had one light on an polaris scrambler 4-wheeler mounted and when you gased it it would get brighter but sa far as the name im not sure you could check ebay

lol, i only know how to make the lights get dimmer as the music gets louder

i did this in a port tube once using LED's, some rectifier diodes, a zener diode, and a couple resistors. the fed from the amp output voltage and had no effect since their resistance was quite high compared to the speaker. the circuit i built works and works well! i have a pic of the port tube illuminated, http://memimage.cardomain.net/member_images/1/web/337000-337999/337617_68.jpg that circuit still works today after three years! just recitfy the audio signal put a 9V zener diode in parallel with one or two LED's and a drop resistor (calculated at 9V) then put a larger resistor in series with all that to account for the high voltage levels available at your amplifer output. that larger resistor value may be between 100 and 200 ohms depending on the amp and desired brightness. you can parallel additional LED and drop resistor pairs, but realize that you will begin to take away from the sub. now if you have some small cheap amp you may be able to dedicate it to running your car led's. Now, if instead you want an circuit that can feed entire car lighting then i would run it off the low level signals in your audio system (possibly some low level outputs on your amp) an design a circuit where you use a transistor as an amplifier of sorts (maybe a common-emitter configuration?). i have been meaning to design this type of circuit for some time but have just been too busy. if anyone has already designed such a circuit let me know how it worked out for you. i have a pretty good idea in my head how to make it happen. it all depends on how much current you need to feed the number of LED arrays. Electrons behave like waves on monday, wednesday, and friday, like particles on tuesday, thursday, and saturday, and like nothing at all on sunday.

This is exactly what I was looking for thank you for the post. I will take pics when im done.