DIY laser controller

[DJDoubleYou]

I want to make a controller, that sends a note when a laser beam is interupted.
I tought i saw these lasers on sparkfun but i can't find them anymore.

Basicly i want i to act like a sort of button.
When the beam is interupted it should be "pressed" and when it's not interupted, not pressed.

If something like that doesn't exist, i've got another idea, Just a regular laser and a photocell with a comparator atatched to it, wich is followed by an invertor (NOT-Gate).

If you guys would give me a link, or a opinion on my backup plan it would be great.

ps. Sorry for my grammar mistakes and words that i may have translated wrong

[Patch]

http://www.synthtopia.com/content/20...di-controller/

[Patch]

http://www.ebay.co.uk/itm/Alesis-Air...#ht_619wt_1270

[DJDoubleYou]

not exactly what i'm looking for

edit: here is a good example

https://www.youtube.com/watch?v=wJNo0wu5VHM