Ultra-Low Power MEMS Inertial Switch Based Wake-Up Wireless Sensing Node for Door Lock Monitoring

We present the first demonstration of our event-driven ultra-low power MEMS inertial switch for dry cabinet door lock monitoring. The MEMS inertial switch is integrated into a wireless sensing node (WSN) which houses a commercial accelerometer (ADXL355) and Bluetooth Low Energy (BLE) module to detect the door lock status. Upon the acceleration generated by unlocking of the dry cabinet, the MEMS inertial switch is turned on and wakes up the BLE module and the accelerometer sequentially. After wake-up, the BLE module streams the accelerometer data to a remote PC tracking the activities on the dry cabinet door. The inertial switch successfully detects the door unlock events and wakes up the WSN to stream the accelerometer data for 2 hours. The data signature of the accelerometer is able to classify the status of the opening, closure and locking of door.