A laser harp is a 'musical instrument' that uses inexpensive laser pointers and photocell sensors to create virtual 'strings' that can be plucked to simulate a real harp. In this case, the MIDIsense board is used to interface the photocells to the computer or synthesizer.

You can buy photocells at any electronics store, the cheap laser pointers are always on eBay or giftshops, etc.

	You'll need a MIDIsense board, with a photocell sensor and a matching resistor. I'm using the default setup here. You'll also need some tape and a $3 laser pointer, available at low-quality gift stores everywhere.
	Tape down the button on the laser pointer so it stays on.
	Set up your MIDIsense and laser pointer so that the laser his the sensor, I propped it up with a magnet.
	Start out by just verifying that the sensor is working properly, when you break the beam the pointer should move to the left some.
	Change the type to "Note On/Off"
	Lets calibrate the sensor now. For Note On/Off we actually want to set the min/max calibration points to be between the min and max of the sensor.
	Set the calibration, now test by breaking/making the beam.