A minimalist wireless instrumented shoe design to measure foot clearance in human gait

• Foot clearance is crucial and is associated with risk of trip and fall. • The instrumented shoe can be worn comfortably for daily living activities. • The results were validated against the optical motion capture. • The measurements are accurate and reflect the user’s natural gait. Optical motion capture system is commonly used to measure the dynamics of the foot during walking. However, it is expensive and only captures limited gait cycles, restricting its ability for long term gait monitoring. This study proposes an affordable and minimalistic instrumented shoe design that can quantify the characteristics of heel and toe clearances in gait. The shoe was equipped with four laser Time of Flight (ToF) sensors and two Inertial Measurement Units (IMU). The results were compared against the data collected by motion capture system. The instrumented shoe can measure foot clearance with average Root Mean Square Error (RMSE) of 6.48 mm and 11.00 mm for toe and heel clearances. The proposed design is light and compact and it does not alter the wearer’s natural gait. It allows the measurement of foot motion during walking in an open and uncontrolled environment and the risk assessment of trip and fall.