Study and implementation of a wireless accelerometer network for gait analysis

Stamatakis, Julien [UCL] Gerard, Pierre [UCL] Drochmans, P. Kezai, Tahar [UCL] Caby, Benoît [UCL] Macq, Benoît [UCL] Flandre, Denis [UCL]

The purpose of this work is to develop a new wireless system implementing a network of accelerometers, based on the IEEE communication Std. 802.15.4, for gait analysis. 3-axis accelerometers are indeed well adapted for characterizing gait features. The IEEE 802.15.4 standard enables 250 kbps data transfers with very low power consumption. Our network of 10 such RF nodes with 3-axis accelerometers can record accelerations up to +/- 10 g and shocks up to 50 Hz for tests on walking and running subjects. Accelerometers have been calibrated according to battery voltage and temperature variations. The average node power consumption is 14 mA, which allows 55 hours of use with two AAA batteries. A base station, connected to a PC, controls the whole 10 nodes system and collects the recorded data. Validation tests have shown that the system handles possible transmission problems. The system is robust and allows real time visualization of accelerations. The system could be easily reconfigured to incorporate other sensors.