Optical sensor and electric stringed musical instrument with digital interface (MIDI) equipped with optical sensor

A stringed musical instrument with a digital interface comprising:

• a body,
• at least one string stretched over said body,
• an optical sensor comprising a housing attached to the surface of said body of the stringed musical instrument, at least one optical emitter and at least one optical receiver located on said housing so that a light beam of at least one optical emitter forms a light spot that completely covers a photosensitive surface of at least one optical receiver, with at least one optical emitter and at least one optical receiver being located under the same string,
• wherein
• said optical emitter generates light beams,
• said optical receiver comprises at least two photosensitive surfaces, forming, together with said optical emitter, at least two optical pairs, a lower one and an upper one respectively,
• a light beam modulator located between said optical pairs, covering a part of each of the photosensitive surfaces, and configured to be fixed to a string and configured to change an area of an illuminated part of the upper photosensitive surface and an area of an illuminated part of the lower photosensitive surface when a string, with said modulator attached thereto, deflects in horizontal and vertical planes, respectively.