laser controlled drum kit

This is my first project of my own design and first off I would like to know if it is even possible. Secondly I would like some help with the coding if it is possible.
My idea is 5 laser diodes emitting a continuous beam and they are shining into ether photo resistors or some other light sensor. When the beam is broken the Arduino would send a signal to a Wave Shield to play a sound file. Also I would like to have a Piezoelectric disc that when tapped the wave shield plays a base drum sound.

I have attached a crude drawing of my basic idea.

arduino project idea.bmp (765 KB)

I would like to know if it is even possible.

Yes, it is.

Secondly I would like some help with the coding if it is possible.

The code depends on which laser diodes you are using, which light sensors, and which wave shield. And, of course, how they are connected to the Arduino. A few more details would help.

Turning the laser diodes on is easy - digitalWrite() HIGH to the pin the laser is connected to (or, more likely the pin that the transistor that controls the laser).

Reading the light sensors is easy - analogRead() from the pin, if they are analog sensors or digitalRead() if they are digital sensors.

The wave shields typically come with a library that allows you to trigger playing some file. Exactly how to do that depends on the library.

Piezo sensors may or may not be sensitive enough, depending on the specific sensor, without amplification.

I am thinking about using the wave shield from ladyada.net http://www.ladyada.net/make/waveshield/ and I haven't looked into what laser diodes and what light sensors I am going to use.

Try a search for Laser Harp, it uses the same kind of response you are after. Might also the the MP3 boards here www.mdfly.com several have seperate triggers for each sound. Don't know about multiple sounds at one time - that may require a card per sound, and then analog mix out to your amplifier.

Also I would like to have a version of the code to play guitar instead of drums. If I have a version to play guitar I would want to have the ability to play the entire treble cleft. So would the digital pins work instead? Or would I need to get a Arduino Mega?

Lets back up a bit - start with defining how many notes you want to play, do you want the trigger to play pre-recorded sounds or to create the sounds, how many sounds you want played at one time), etc. For guitar - you mean like a 1-string guitar? If not, how would you propose keeping your fingers out of the way while playing chords for instance?

I would like to have 1 sensor for each note. So 1 sensor is C, 1 sensor is G and so on and I would use prerecorded sounds.

So how many sensors and lasers? You are trying to run before you can even crawl here. Get just one "string" going first. Then think about expansion.

I'm thinking about 7 sensors and 7 lasers but I don't think the lasers need to be connected to the Arduino because they are only emitting a continuous beam.

would the TSL235R light sensor be good for this?

No.