Wake-up iot wireless sensing node based on a low-g threshold mems inertial switch with reliable contacts

We demonstrate a wireless sensing node (WSN) that is woken-up by a Microelectromechanical systems (MEMS) inertial switch with low-g threshold of 9.4g for Internet-of-Things (IoT) applications based on zero-power event-driven sensing. By virtue of the device design and fabrication of the switch contacts, the inertial switch in the WSN maintains a contact time long enough to wake up a Bluetooth Low Energy (BLE) module. Upon wake-up, the BLE module initiates data transmission to a remote display, when the WSN senses an external acceleration above the threshold. We also demonstrate remarkable contact reliability in the MEMS inertial switch as a significant step towards long lifetime zero-power sensors. The inertial switch output shows little degradation even after 100 cycles of testing under ambient conditions with an unpackaged MEMS device; a notable first among MEMS inertial switches.