Application of Force Sensing Resistor (FSR) in Design of Pressure Scanning System for Plantar Pressure Measurement

Abstract

This paper aims at development of low cost dynamic foot pressure scanner. To estimate the peak pressure points on the foot sole, a study was conducted on a healthy male group. In all, 8 subjects were placed for observation on EMED (from Novel Inc.) foot mat system at different clinics. The data, thus recorded, was analyzed using Novel-Win-Mask software and it is concluded that, on a single pressure head for a normal person, the deviation from mean value is not too much. Hence in case of a normal foot, the peak pressure points are heel, 1st, 3rd, 5th Meta tarsal head (MTH) and toe. Although 5 points for plantar pressure analysis look sufficient but one can add few more points to provide a complete coverage of pressure distribution on shoe sole. Using this data, shoe sole of different sizes were developed with 8 force sensing resistors (FSR) placed in each sole. The sole was connected to multi-channel Biopac MP100 data acquisition system (DAS) through an amplifier circuit. The USB interface is provided between DAS and the computer system. The data recording and analysis was performed using data acquisition software Acq. 3.7.3. The developed system is flexible and portable for field studies and also advantageous due to large memory size, dynamic recording of pressure and no fear of foot step modification. The data analysis can provide early information regarding diabetic foot ulceration and also could be used for shoe sole design.