The Amulet Wearable Platform: Demo Abstract

In this demonstration we present the Amulet Platform; a hardware and software platform for developing energy- and resource-efficient applications on multi-application wearable devices. This platform, which includes the Amulet Firmware Toolchain, the Amulet Runtime, the ARP-View graphical tool, and open reference hardware, efficiently protects applications from each other without MMU support, allows developers to interactively explore how their implementation decisions impact battery life without the need for hardware modeling and additional software development, and represents a new approach to developing long-lived wearable applications. We envision the Amulet Platform enabling long-duration experiments on human subjects in a wide variety of studies

Amulet: An Energy-Efficient, Multi-Application Wearable Platform

Wearable technology enables a range of exciting new applications in health, commerce, and beyond. For many important applications, wearables must have battery life measured in weeks or months, not hours and days as in most current devices. Our vision of wearable platforms aims for long battery life but with the flexibility and security to support multiple applications. To achieve long battery life with a workload comprising apps from multiple developers, these platforms must have robust mechanisms for app isolation and developer tools for optimizing resource usage.\r\n\r\nWe introduce the Amulet Platform for constrained wearable devices, which includes an ultra-low-power hardware architecture and a companion software framework, including a highly efficient event-driven programming model, low-power operating system, and developer tools for profiling ultra-low-power applications at compile time. We present the design and evaluation of our prototype Amulet hardware and software, and show how the framework enables developers to write energy-efficient applications. Our prototype has battery lifetime lasting weeks or even months, depending on the application, and our interactive resource-profiling tool predicts battery lifetime within 6-10% of the measured lifetime

An Analysis of Bluetooth Low Energy in the Context of Intermittently Powered Devices

Bluetooth Low Energy (BLE) has become a prominent low-power wireless solution for portable, battery-powered devices, potentially allowing them to run for several years, even off of a simple coin cell. But batteries must still be replaced. The emergence of batteryless devices is gaining momentum due to their ability to run for decades with no maintenance. The design of BLE relies on exact timing, which usually means a constant power source. The question, then, is how well will BLE function when used in batteryless sensors that run on harvested energy and therefore lose power frequently. In this paper, I evaluate the suitability of using BLE in the context of these Intermittently Powered Devices by analyzing the energy requirements of the three main BLE events: an advertisement, the connection establishment, and the periodic connection event. I then apply the results in an evaluation of BLE on a Periph-eral powered by harvested solar energy and compare and contrast connectionless broadcasting and connection-oriented operation. The results show that batteryless BLE devices are not limited to connectionless operation as convention suggests, and that connected devices have the potential for better performance overall. Based on these findings, I describe a modified BLE protocol that would allow for sustainable connection-oriented operation to make it a more effective wireless standard for IPDs