Bela-Based Augmented Acoustic Guitars for Sonic Microinteraction

This article describes the design and construction of a collection of digitally-controlled augmented acoustic guitars, and the use of these guitars in the installation \textit\{Sverm-Resonans\}. The installation was built around the idea of exploring `inverse' sonic microinteraction, that is, controlling sounds by the micromotion observed when attempting to stand still. It consisted of six acoustic guitars, each equipped with a Bela embedded computer for sound processing (in Pure Data), an infrared distance sensor to detect the presence of users, and an actuator attached to the guitar body to produce sound. With an attached battery pack, the result was a set of completely autonomous instruments that were easy to hang in a gallery space. The installation encouraged explorations on the boundary between the tactile and the kinesthetic, the body and the mind, and between motion and sound. The use of guitars, albeit with an untraditional `performance' technique, made the experience both familiar and unfamiliar at the same time. Many users reported heightened sensations of stillness, sound, and vibration, and that the `inverse' control of the instrument was both challenging and pleasant.