Sensor development
Excerpt from PhD-thesis: Michael Weilguni, "Force Sensors for the Measurement of Finger Forces in Clarinet Playing", Technische Universität Wien, 2013.
![6sensor-coin.jpg](https://www.mdw.ac.at/upload/MDWeb/iwk/img/6sensor-coin_newcss.jpg)
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:
![7ring-btm.jpg](https://www.mdw.ac.at/upload/MDWeb/iwk/img/7ring-btm_newcss.jpg)
Hand-made ring sensors including three (black) instrumentation amplifiers (AD8235, 2,2 × 1,5 mm²) and 11 soldering points on the back side.
Layout:
![8tracks3d.jpg](https://www.mdw.ac.at/upload/MDWeb/iwk/img/8tracks3d_newcss.jpg)
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:
![9asensor-on-hole.jpg](https://www.mdw.ac.at/upload/MDWeb/iwk/img/9asensor-on-hole_newcss.jpg)
![9bsensor-on-hole-cap.jpg](https://www.mdw.ac.at/upload/MDWeb/iwk/img/9bsensor-on-hole-cap_newcss.jpg)
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.