SNA-MEMS Batteryless-Wireless Sensing Module utilizing RFID System

Summary form only given. The network sensing systems connect various sensors by wire in order to collect information measured by each sensor. Although, the wired connection causes certain restrictions regarding with the system installation. Consequently, many kinds of research on wireless sensor network systems have been developed. However, almost all commercialized products utilize a battery as the power source. But, the battery exchange process is needed and therefore the setting condition is restricted, again. Furthermore, the management cost of the battery is troublesome. In order to solve these problems, we have proposed the wireless network sensing system with sensor modules with MEMS sensor and without battery by applying the RFID system for power transmittance. Based on this concept, the unique sensor module SNA-MEMS (smart nano micro electro mechanical systems) is developed for the demonstration. This module is driven by the electric power converted from radio wave at the in-module circuit to realize the battery-less concept by following the RFID standard, ISO 15693 13.56 MHz. The demo-model has a piezoresistive 3-axes MEMS acceleration sensor and consists of eight 1cm x 1 cm ceramic boards those are stacked vertically. Each board is connected to the next boards by soldering between through-hole bus located on outer rim of each board. The electric circuit in the modules has following circuit blocks: antenna, interface, power generation, reception, transmission, sensor, multiplexer, and MPU embedded ADC boards. In this paper, the concept of battery-less and wire-less sensing network with the details of developed sensing module, SNA-MEMS is introduced.