Help making synch-with-music lights?

Hi, I have a strip of LED's and want to connect them so they synch with music (just so they flash to the sound not some fancy microcontroller stuff) and I was wondering how would I connect them because if I try to just connect them to my amp they dont come on as it's not powerfull enough, I read you can use a transistor in this case but I thought that transistors just switched on and off and not varied with the volume. If I should use a transistor could someone suggest one for me (preferably out of Maplins.co.uk). The whole strip uses 12V. I also noticed that it works ever so slightly when you unplug the speaker and have just the LED's plugged in - is there any way to get around this?

Thanks


orksecurity7 years ago
Websearch "color organ".
kacper00100 (author)  orksecurity7 years ago
Nonono...thats exactly what i dont want, I assume that youre talking about the expensive microcontroller thing. I just want to make some lihts that beat with the music
No, that's exactly what you do want. A traditional color organ is just an amplifier feeding three filters (low/medium/high), with the output of those filters being used to control the brightness of the controlled channel.  Cheap analog parts. The design's been around since the 60's if not earlier.

As I said: Websearch "color organ". You'll find simple designs.
kacper00100 (author)  orksecurity7 years ago
Hmmmm....I'd rather make it myself if I can to be honest. I made a quick circuit diagram. Do you think it would work? This is the transistor BC547C

Thanks
lights.bmp