Abstract
This work presents a wirelessly powered, buried soil moisture sensing system. The system is electrically charged by a low-frequency electrodynamic wireless power transmission scheme. A coin-cell secondary battery and battery management system provide an energy reservoir, which supplies power to a capacitive soil moisture sensor connected to an ESP-8266 Wi-Fi SoC for transmitting data. Buried at 30 cm from the wireless power transmitter, the 17 cm3, three-phase, rotating-magnet receiver produced an average power of 230 mW. The system demonstrated a time averaged energy transfer of 0.272 W-hr. The soil moisture data was transmitted to an IoT cloud platform for remote monitoring.
Fig. 1: Electrodynamic Wireless Power Transfer to buried sensors.
