They have many uses in the medical industrial sector, but their wide pressure range, and their sturdiness, make them particularly suitable for the automotive sector: for example as elements for hydraulic pressure measurement in the ABS systems, or for the measurement of the pressure of aerodynamic breaks and pneumatic transmissions.
Piezoresistant pressure sensors are made up of a silicon chip, which has the property of modifying its resistance when it is subjected to a mechanical stress.

Keller is one of the leading company in the process treatment of the resistance supplied silicon chip that constitutes a sort of Weathstone bridge.

Normally you start from a diffused Boro N type chip until creating P type strata which, in this context, make up the resistances. Primary causes of the piezoresistant effect to be exploited are: a longitudinal one, that increases resistance; the other transversal, with a decrease.
 
In the production process the most complex factor concerns the mechanical production of the sensor and the fixing of the mechanical support.