Exhibit: Light Harp

‘Pluck’ the laser beams to play a little light music!  You are really controlling a computer which produces musical tones.  The harp has narrow red laser beams which take the place of strings.  Each beam shines down onto an electronic sensor which are able to sense whether red light is reaching it or not.  The harp has a musical scale of recorded notes stored in its computer memory.  When a beam is ‘plucked’ the sensor sends a signal to the computer which plays the appropriate note.  The note begins as the finger moves out of the way of the beam, in just the same way that a real string begins to vibrate when it is released by the finger.