How does a Force-Sensitive Resistor work?
Does it work by sensing the number of tracks the user covers meaning that the more force the user pushes on the sensor the less resistance it causes?
Here is a picture of one:
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Sign up to join this communityHow does a Force-Sensitive Resistor work?
Does it work by sensing the number of tracks the user covers meaning that the more force the user pushes on the sensor the less resistance it causes?
Here is a picture of one:
A piece of flexible conductive material with a high resistance is under the tracks, and the resistance between the tracks reduces when the sensor is pressed.
I once made a crude one from a piece of conductive foam, which worked in a similar fashion.
Piezo film is another technique that is sometimes used. I've also experimented with that, and it works very well.
The one you picture here is a polymer film that has conducting particles held within it (think of something like novolac resist or SU8 with metal micro-particles evenly distributed within it). The film has a non-zero conductivity.
When you press on it some of the micro-particles touch, increasing the conductivity. Pretty simple.
It's not the same as the piezo-resistive effect, which depends on the shape of a crystal lattice in the atomic structure. when you bend it, the crystal lattice either expands or contracts, causing the resistance to increase or decrease because of a slight change in the energy bands of the crystal.