Optimal placement of accelerometers within the constraints of a smart garment system

The aim of this study was to investigate the effects of accelerometer placement, within the practical constraints of a smart garment, for the purposes of monitoring gross levels of activity. Experiments involved collection of data from three participants who were instructed to walk on a motorized treadmill at speeds of two, three and four miles per hour. Accelerometers were placed on a specially designed harness in an array like configuration around the torso. Data obtained from the accelerometers attached directly to the body and those placed within clothing were compared. Noticeable differences in signal amplitude and noise were apparent, however, this noise can be removed using appropriate signal processing techniques. Data was also collected using eight Shimmer devices controlled by a bespoke application created in BioMobius. Data from the eight devices was compared by visual inspection. Results showed that there was no significant difference in accelerometer output due to placement on the back and front of the torso. An adaptive threshold algorithm was also utilised to compare step counts at each of the positions. No large differences in step counts where observed between devices placed at the various positions.