And the best part is that I can get the lasers at less than 5$ from ebaym just hope that they dont get busted in customs, now what about the sensors to sense the laser?
To account for wabble room, I'd use small solar cells (they are bigger than photoresistors/transistors... atleast the ones I can get at radioshack). As i mentioned in my first reply, you can use an arduino's analog pin to measure the voltage they produce.