Magpick (2018)

The Magpick is an augmented pick for electric guitar that uses electromagnetic induction to sense the motion of the guitar pick while Bela analyses, processes and translates this motion into nuanced, low latency sonic interactions. The augmented pick contains a coil of copper wire and senses guitarists’ gestures by interacting with the magnetic field generated by any guitar pickups. A voltage is generated, which relates to the motion of the pick with respect to the magnets in the guitar pickup, and this in turn gives information about the gestures of the plucking hand. Thanks to Bela, this information is captured with high resolution, and low latency, and it is used to modify the guitar sound in ways that can be compatible with existing guitar techniques. The technology is minimally invasive, as it doesn’t require additional hardware to be installed on the guitar.

The most significant features of the pick signals are: they are created only when the guitarist strums over the pickup area (as opposed to over the fretboard, for instance); they respond to pick motion above the strings (not necessarily touching them); that they sense the intensity of movement with a wide dynamic range. To maintain a good signal-to-noise ratio with such a small signal, two specialised amplifier circuits were designed. Each amplifier produces a type of signal, which we’ll refer to as integrator and proportional, with different characteristics. The integrator signal (see image below in blue) is useful to detect slower motions, such as waving the Magpick above the magnets. The proportional signal (see image below in orange) is suitable for detecting high-frequency transient events such as the snap of the pick following plucking a string. The amplified signals were connected to two analog inputs of a Bela Mini. The signal from the electric guitar (guitar-signal) itself is connected to a third input. In the Bela board, the three signals are combined with a Pure Data patch that processes the sound to be sent to the guitar amplifier.

  • Ideation
  • Development
  • Pick design
  • Sound design
  • Evaluation
  • Andrea Guidi
  • Andrew McPherson
  • Adan Benito
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