Abstract
The advent of the Internet of Things (IoT) has given rise to a new class of embedded systems that combine short-range, low-power wireless communication with proximity sensing, inertial sensing, and real-time clock (RTC) in a miniature package. Such a system can be very useful in collecting contextual information for its user, including user behavior or gesture, user location, orientation, and motion, user encounter with other users or objects, and time. Such context can be crucial in making pervasive electronic systems behave in a truly intelligent way. Unfortunately, there have been few platforms to date that can provide all the necessary features.In this thesis, we present EcoMini, a new wireless motion-sensing node with RTC and Bluetooth Low Energy (BLE) radio transceiver, all in a miniature size of 12 mm × 9 mm. It uses the same programmable microcontroller unit (MCU) for both the BLE protocol stack and application code. BLE enables direct connectivity to smartmobiles and PC/Mac computers without the inconvenience of a dongle or gateway. The 9 degree-of-freedom (9-DoF) inertial sensor includes a digital triaxial accelerometer, a gyroscope, and a compass in one package. Its threshold detection feature enables effective motion-based power management. The contributions include a balance between power, size, and expandability. This system has been used for easy, efficient implementation of several IoT devices, including a motion-enabled proximity tag, an air-mouse, smart slippers, and person- identifying cabinet doors.