Measurement of Resistance/Force Conversion Characteristics of FSR Elements for Evaluation of Contact Skin Pressure by PPG Sensors

This paper describes realization of a simple measuring tool for easy, but precise investigation of resistance/force conversion characteristics of force-sensitive resistors (FSR) by comparative measurements with the help of calibration weights. Due to proposed further use of FSRs in measurement experiments with human subjects, only a lower part of the force range (up to 250 grams) was investigated. Then, a linearization of depicted FSR’s conversion characteristics based on the linear regression was performed. This is important for practical implementation into the control program of the currently proposed prototype of a wearable multi-sensor working on a photoplethysmography principle.