Calibration of force sensing resistors (fsr) for static and dynamic applications

This article shows a procedure to calibrate Force Sensing Resistors (FSR), whose manufacturers rarely offer calibration details. Literature and experience show that, due to the nature of FSR construction, its time dependency makes it hard to calibrate at first glance by simple measurements. The methodology employed is based upon the comparison of the measured data obtained from a FSR with the one obtained from a calibrated load cell. The force loading and unloading processes are performed automatically with a mechatronic device which allows having time invariant and variant force profiles. Special analysis is taken over creep and hysteresis compensation along with its relation with static and dynamic applications with the help of existing literature. At the end a time dependant function is obtained that relates the force applied on the sensor, and the signal obtained from it, allowing for the use on applications to measure force and pressure in ranges from 0 to 20N and 0 to 100mmHg respectively.