Investigation on Smart Cushion Based on SFS Structure and its Application in Physiological and Activity Monitoring

A smart cushion based on SFS (single-mode-few-mode-single-mode) structure is proposed and experimentally demonstrated, which can be applied in physiological and activity states monitoring simultaneously. The sensing unit embedded in a common cushion is designed as a sandwich structure, consisting of a piece of fiberglass mesh, a SFS structure layer and a polyvinyl chloride (PVC) layer thus the sensitivity can be significantly enhanced. With off-line processing and analyzing of the raw signals collected from the cushion system, the heartbeat rate (HR) and respiratory rate (RR) can be obtained with the maximum error of 1 bpm and the activity states on the cushion can be clearly distinguished within the accuracy of one second. Such a smart cushion has the advantages of low cost, compact structure and high comfort, especially suitable for office workers and the elderly in nursing homes.