Screen Printed Capacitive Free-standing Cantilever Beams used as a Motion Detector for Wearable Sensors

This paper reports the screen printing of free-standing cantilever beams on to fabric, for use as motion detectors. Such low cost motion detectors could be used in clothing as activity monitors to indicate if the wearer is unconscious in safety critical applications, e.g. a fireman in a building. We have fabricated capacitive free-standing cantilevers by screen printing sacrificial and structural materials onto a fabric substrate. In this paper, these devices are used as motion detectors which are mounted and tested on a human forearm alongside a commercial accelerometer, for comparison. The results show the feasibility of using a fabric based cantilever to indicate that the wearer is moving.