Evaluation of body-worn FPCBs with bluetooth low energy, capacitive touch, and resistive flex sensing

Abstract

Commercially available flexible printed circuit boards (FPCBs) have the potential to embed electronics, connectivity, and interactivity into the same surface. This makes them an ideal platform for untethered and interactive wearable devices. However, we lack an understanding how well FPCB-based antennas and sensors perform when worn directly on the body. This work contributes an understanding by studying body-worn FPCBs in three technical evaluations: First, we study the integration of Bluetooth Low Energy and compare the signal strength of our body-worn FPCB with a rigid BLE developer board. Second, we study the accuracy of capacitive touch sensing with two electrode sizes. Finally, we develop a resistive flex sensor based on commercially available FPCB materials and compare its accuracy with a state-of-the-art flex sensor. Taken together, our results demonstrate a high usability of FPCB-based wearable devices.