Block 1: Pressure and Distance Sensing

Title: Pressure ad Distance sensing

Credits: Admar Schoonen and Troy Nachtigall

Year of invention: 2015

Description: The well known resistive pressure sensor made with velostat, but now with a twist: the same sensor can also be used to measure presence using capacitive sensing. By combining both sensing methods, the same hardware can work both as distance sensor and pressure sensor. And when a small hardware change is added, it is also sensitive in only one direction (ignoring the human body on the other side).

The workshop assumes you are familiar with Arduino and basic electronics such as a voltage divider.

First half of the workshop will cover theory of resistive sensing with Velostat and capacitive sensing to measure distance.

Second half of the workshop will be up for voting for one of these three things:

  1. More in depth theory of capacitive sensing, for example discussing different methods of capacitive measurement (RC method, CVD method or others), guards / shields to make it sensitive to only one side without sacrificing performance etc.
  2. Brainstorm sessions on use cases for such a sensor.
  3. A hands-on where you will experiment with materials and make such a sensor or use the material from the workshop in their own application.

Materials: Arduino, velostat or ESD foam, conductive textile, opamp

Dimensions: ~ 5 x 5 cm for the sensor, ~ 3 x 3 cm for the circuit (excluding Arduino)

Link: https://github.com/admarschoonen/resistive_cap_touch

Photo: coming soon (Troy has them)

Circuit diagram:

wiring_with_shield

given by Admar Shoonen and Troy Nachtigall.

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