JointSAFE: A Wearable, Wireless Motion Sensing System for Hip Rehabilitation

By Ninoshka Singh

The JointSAFE project entails the development of a wearable, wireless body sensor network which aims to monitor and control motion of an operated hip for hip replacement patients during rehabilitation. While monitoring orientation of the upper torso, thigh, and knee on the injured side, the system attempts to provide an early warning signal to alert the patient when they are moving their leg into a position that violates the hip movement restrictions required during the rehabilitation period. JointSAFE is comprised of three motion sensor nodes that calculate 2D orientation of roll and pitch angles using sensor fusion processing, and then wirelessly transmits the orientation data to a central monitoring device, an Android tablet. Each motion sensor node is comprised of a 3-axis accelerometer, 3-axis gyroscope, an alert sensor (LED), a microcontroller, and a Bluetooth RF transceiver module. The microcontroller reads raw data from the accelerometer and gyroscope, calculates orientation, and wirelessly transmits the data via Bluetooth to the Android Tablet. The Android tablet provides a GUI-based user application which manages the receiving of data from each sensor node, calculates the high level hip motion restriction parameters, and displays real-time data to the user.