Strumbot – an overview of a strumming guitar robot

Abstract

StrumBot is a novel standalone six stringed robotic guitar consisting of mechanisms designed to enable musical expressivity and minimise acoustic noise. It is desirable for less than 60 dBA of noise at 1 m to be emitted to allow StrumBot to play in intimate venues such as cafés or restaurants without loud motor noises detracting from the musical experience. StrumBot improves upon previous robotic musical instruments by allowing additional expressive opportunities for a composer to utilise. StrumBot can perform slides, vibrato, muting techniques, pitch bends, pluck power variances, timbre control, complex chords and fast strumming patterns. A MIDI input allows commercial or custom controllers to operate StrumBot. Novel note allocation algorithms are created to allow a single MIDI stream of notes to be allocated across the six guitar strings. Latency measurements from MIDI input to string pluck are as low as 40 ms for a best case scenario strum, allowing StrumBot to accompany a live musician with minimal audible delay. A relay based loop switcher is incorporated, allowing StrumBot to activate standard commercial guitar pedals based on a MIDI instruction.