“The laser harp was born as a remake of an old project. The basic idea is to create a variation of a classic instrument such as the harp using current electronic technologies, such as microcontrollers, sensors and speakers.
The structure is made of wood. It has the shape of a rectangle of 96x47x6 cm. On the longer sides there are two separate circuits: on one there are six lasers in a row aligned with the six photoresistors placed on the opposite side.
Lasers (in series) are powered by a 4.5 V battery. The circuit that regulates the photoresistors is a bit more complicated: each photoresistor is connected to an analog input pin on an Arduino.
Arduino powers this circuit and controls the sound output through the program loaded on the board. The program performs a first evaluation of the light intensity detected by the photoresistors and sets the red laser light as standard. Once this is done, every time the laser beam is interrupted, an input pin detects a voltage change and the arduino calls a music shield library function to play the note associated with the specific photoresistor.
Having fun creating music, in a new and captivating way, is the purpose of this project. Our team wanted to amaze viewers by playing something cool and fascinating such as a harp without real and tangible strings.”