One part musical interface, another part lighting display, all sorts of awesome. The laser harp is a device that projects laser beams that, once blocked by a musician —or crafty engineer, produce sounds similar to that of a harp or lyre. A number of popular musicians have utilized the laser harp in their live performances, such as Jean Michel Jarre and Little Boots. The devices have also made appearances in numerous art installations worldwide.
Creating rudimentary laser harps are an attractive project for hobbyists with an engineering background. It is far from a Pinterest weekend D.I.Y tutorial, but not out of the realm for those with some time and about $100 bucks to spare.
This Instructibles post utilizes a Arduino Uno board, which is commonly used for entry level electronics and coding work, as the base for a simple laser harp. Using materials that can be found on Amazon or at your local electronics store, a little bit of electronics and optics know-how, and some light coding, you too can make your very own laser harp.
The laser harp vaguely resembles a string instrument, with multiple, straight beams lining the device. The laser harp utilizes multiple photodiodes or photoresistors on either end of the device’s frame. These are how a “break” in the laser is detected, when the harp is “played”. Like in the above tutorial, these laser harps require a very low powered beam, such as the one found in a standard handheld laser pointer. When the emitted beam is “broken,” or in other words, played, a sound is emitted using a MIDI controller that switches on and off, based on the consistency of the beam. Think of an improperly wired light switch, turn it off and the light comes on. Turn it on, and you’re left in the dark. The absence of laser beam contact triggers the device to startup. In the case of a laser harp, the interruption emits sound.
Of course, laser harps developed for performances and instillation art require more than a handful of steps to develop, and pose many more potential safety hazards than the D.I.Y versions. The laser harps used by professionals are higher powered requiring a higher knowledge of laser safety in application. The video below gives a brief rundown and demonstration of a D.I.Y laser harp, which can be held in sharp contrast to the professional performance video above.