Demonstration of Wireless Access to Batteryless and Antennaless Sensors Distributed on Clothes

Abstract

Tiny sensors, such as temperature and posture sensors, distributed over the body surface will provide more detailed information about the body’s status than a single-point measurement by sensor-loaded wearable devices including smartwatches. Power/data transfer to/from the distributed tiny sensors is an inevitable issue. In this presentation, wireless access to batteryless and antennaless sensors distributed on a conductive textile will be demonstrated. A double-sided conductive textile is used as a power and signal transmission bus. The two conductive surfaces, isolated from each other, work as a transmission line that conveys dc power and radio-frequency (RF) signals simultaneously. In the demonstration system, two RF carriers are modulated with Inter-Integrated Circuit (I2C)-formatted digital signals to transfer bitstreams from each sensor. Hence, the system is compatible with off-the-shelf I2C-interfaced digital sensor ICs. A demonstration system with distributed temperature sensors will be presented as an example of implementation; nevertheless, other various sensors, e.g., humidity sensors, accelerometers, and electromyography sensors, can be utilized in the same system.