-- Posted by Hi Jack at 3:45 am on Aug. 16, 2008 I want to build lights to put in my drum kit so that when i hit them they light up. I know i need a piezo transducer and lights, i'll run each one off it's own battery (don't know what voltage yet) does anybody know what circuit i'd need, i'm thinking battery>piezo>led (do i need a resistor?). here are the led and piezo I am using: LED http://www.maplin.co.uk/Module.aspx?ModuleNo=35834&doy=16m8&C=SO&U=strat15 Piezo http://www.maplin.co.uk/Module.aspx?ModuleNo=3202&C=Maplin&U=SearchTop&T=piezo&doy=16m8 and does anybody have ideas for an LED diffuser so it lights up a large area of the drum head instead of just a patch? -- Posted by marissac at 3:46 am on Aug. 16, 2008 nope sorry -- Posted by Niddan at 3:46 am on Aug. 16, 2008 Im a drummer ! good idea but apparantley it interferes with the drummers frame of mind whilst playing and can mess up thier rhythm stick to light up drum sticks   -- Posted by ronda at 4:12 am on Aug. 16, 2008 that sounds like a very cool idea! -- Posted by whimsy at 3:49 pm on Aug. 16, 2008 I'd weigh up the benefits of each power option, just personally I think it would be better to have some sort of cheap quick connect on each one, then plug them into one central battery or wall plug pack. That way you don't have to deal with checking or replacing batteries in each unit. Plus you can then have a switch or something if you want to turn them on or off.     Diffusers, I've seen some lenses or diffusers for luxeon leds... like so:   http://www.luxeonstar.com/fraen-wide-beam-lens-without-holder-fits-k2-leds-p-346.php Problem is you probably don't really want to use a luxeon as they're power hungry, you'd probably have to look at switch mode power supplies for them and they get hot so like to be heatsinked... oh and they're pretty expensive. On the plus side they are really, really bright. Maybe have a better look on maplin or some other suppliers, like Farnell and RS, I may have seen some for standard leds before or there could be something you could retrofit, like say a flashlight lens or something. The actual circuit won't be as simple as connecting a transducer and an led together. I'm too tired to think right now, it'll depend but I'd imagine the transducer wouldn't be able to drive the led directly . So you're probably looking at the very least a transducer, led, transistor and a few resistors.