Desenvolvimento de um Theremin óptico digital com síntese de áudio e interface gráfica

Abstract

The Theremin, in addition to being one of the first electronic musical instruments, has the particularity of not requiring physical contact to perform it, since, to do so, it is only necessary to bring your hands closer or farther away from the instrument’s antennas, in which the antenna positioned on the right controls the frequency and the left controls its loudness. Given this, Gomes et al. (2009) developed a Theremin with ultrasonic sensors, using a DSP to map the distance of the hands about the sensors, applying an FM synthesis to generate the sound, and even relating colors to musical notes through Emitting Diodes of Light (LEDs) Red-Green-Blue (RGB). In this project, an optical digital Theremin with a graphical interface was developed, with good cost-effectiveness, timbre diversity, and ease of interaction. For this, two optical sensors were used, responsible for measuring the distance about the instrument. Through a microcontroller, the captured data is processed and sent via the serial port; then, from a PC, the subtractive synthesis method is applied to generate and modify the instrument’s timbre. In addition, a graphical interface was developed to allow the visualization of the instrument’s parameters, as well as providing options for its configuration. After completion of the prototype, experiments were carried out to verify the distance-frequency relationship, timbre diversity, and cost analysis, for which the prototype had a low relative error for the distance-frequency relationship, ability to create different timbres, and relationship high-cost benefit. Finally, a demonstration of the prototype was also presented through the execution of two musical pieces. With this, it was verified that the instrument can be used by beginner musicians in the introduction to musicalization and the development of musical perception, and also by professional musicians in recordings and presentations.