Sensor development

Excerpt from PhD-thesis: Michael Weilguni, "Force Sensors for the Measurement of Finger Forces in Clarinet Playing", Technische Universität Wien, 2013.

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The blue ring with 8.8 mm diameter is made from LTCC (Low Temperature Co-Fired Ceramics). The white sensing elements are made out of flexible Zirkonium with a piezzo resistive element attached. Three intrumentation amplifiers in the ring provide independent signals to measure finger forces from different directions with a sensitivity of 115 mV/N (maximum load 5 N).

Bottom and top view:

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Hand-made ring sensors including three (black) instrumentation amplifiers (AD8235, 2,2 × 1,5 mm²) and 11 soldering points on the back side. 

Layout:

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Layout of the ring-shaped force sensor, highlighting sensor section B with electronic devices. The calibration and sensing elements are indicated by resistor symbols.

Sensor Clarinet:

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Ring-shaped sensor attached to tone-hole of the clarinet: (left) without POM ring, (right) with POM ring. The surrounded key-work has been dismounted for attaching.