Key Considerations and Experience Using the Ultra Low Power Sensium Platform in Body Sensor Networks

A body-worn monitor termed the LifePebble has been developed for real-time measurement of ECG, heart rate, physical activity (3 axis accelerometer) and optionally skin temperature. The LifePebble incorporates the SensiumTM system-on-chip platform designed specifically for wireless body sensor networks, and achieves robust and reliable operation in a compact and lightweight form factor. An initial target application is described; the real-time measurement of energy expenditure, to encourage positive lifestyle changes for early stage type-2 diabetic patients. This paper describes issues encountered during the design of the LifePebble, particularly related to the ambulatory application environment, and describes techniques developed to ensure reliable operation under such conditions.