keeboard: a multi-sensor finger pressure surface

2003 Bob Gluck


keeboard Click here for a brief Quicktime silent movie
And here for an mp3 of a recent performance (March 30, 2004)



pressurepads

... constructed in layers of pressure and position sensitive Infusion Systems I-Cube sensors and rubber padding ... A keeboard performer can send multiple layers of data to an I-Cube digitizer and software interface (programmed in Max / MSP). It is possible to articulate finger position within an x / y axis, while simultaneously sending other information by pressing on one of four mall square pressure sensors that are positioned on the base of the instrument. All that is required is dexterity and finger independence.

The image to the left shows the rear of the four pressure sensors that have been connected to a thin metal plate. Pressure on the plate is distributed across all four sensors, with the strongest signal coming from the sensor most closely under the finger. Thus, relative levels of pressure can be calculated throughout the plate. The wires underneath connect the all six of these sensors to the digitizer.


The images below show the metal plate, from above (left image) and, the plate covered with one of two larger position sensitive sensors. Each sensor tracks data on one axis. The keeboard has two identical sensors stacked vertically, perpendicular to one another.

metalplatepositionsensor

The next set of images show the keeyboard under construction. On top are two thin layers of rubber sheeting, which cover all of the sensors beneath and forms a playing surface that is slighly pressure resistant to pressure. This forms the center of the keeboard.

thinrubberpadthinrubberprep

Here, below, is the keeboard, nearing completion; thick rubber stripping forms the boundary containing the center playing surface.

nearlydone

Here are three mp3 examples, where five (or more) fingers shape the sounds of two physical models of acoustic instruments (information is on the larger Max / MSP screenshot, below). one, two, three.

Here is an initial version of a Max / MSP patch for the keeboard, in which finger motions control the various parameters of two physical models of acoustical instruments. Click the image for a larger image.

Max / MSP interface

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