Help!: Any Idea on how to Create Sound Trigger

Hello, I am a student in the photo-imaging program at langara college.

I am currently doing a science option for one of my classes and i have to create a sound trigger for a 20D Canon camera.

Does anyone have any idea on where I can get some information/specs on creating the device (I cant just go out and buy one). it has been hard finding any information on this subject and i figured this would be the best place to start looking for help.

Thanks!

Kris

A sound trigger? Youre looking to trip the shutter by some sort of frequency? What kind of sound were you thinking of?

Here's one company that makes a trigger that it says can be used for sound triggering.

Here's another company that makes a device that can be used as a sound trigger.

Here's a company that sells sound trigger kits.

Hiviz also has instructions for DIY:
http://hiviz.com/tools​/triggers/makeown.htm

A friend of mine helped making a trigger for me, can't remember which one it is but there are many DIY pages available for sound triggers, just google it.

Here are a few test pics:
http://www.flickr.com/​photos/mazu/2230901229​/
http://www.flickr.com/​photos/mazu/2231694956​/
http://www.flickr.com/​photos/mazu/2230901293​/

On my 350d a microphone worked for me.

Not the most complex of things and it was set off quite easily, but depending on what you're doing it might work fine for you.

Like "the Clapper" for your camera! Brilliant!!