Wearable technology is gaining popularity, with people wearing everything “smart” from clothing to glasses and watches. Present-day wearables are typically battery-powered, and their limited lifetime has become the critical issue. Most devices need recharging every few days or even hours, falling short of the expectations for a truly satisfactory user experience. This paper presents the design, implementation and in-field evaluation of InfiniTime, a novel sensor-rich smart bracelet powered by energy harvesting. It is designed to achieve self-sustainability using solar cells with only modest indoor light levels and thermoelectric generators (TEG’s) with small temperature gradients from the body heat. The wearable device is equipped with an ultra-low power camera and a microphone, in addition to accelerometer and temperature sensors commonly used in commercial devices. Experimental characterization of the fully operational prototype demonstrates a wide range of energy optimization techniques used to achieve self-sustainability with harvested energy only. Our experiments in real-world scenarios show an average of up to 550 μW for photovoltaic in indoor and 98 μW for TEG with only 3 ° temperature gradient and up to 250 μW for 5° gradient. Simulations using energy intake measurements from solar and TEG modules confirm that InfiniTime achieves self-sustainability with indoor lighting levels and body heat for several realistic applications featuring data acquisition from the on-board camera and multiple sensors, as well as visualization and wireless connectivity. The highly optimized low-power architecture of the presented prototype features image acquisitions at 1.15 frames per second, powered only from the energy harvesters.
InfiniTime: Multi-sensor wearable bracelet with human body harvesting / Magno, Michele; Brunelli, Davide; Sigrist, Lukas; Andri, Renzo; Cavigelli, Lukas; Gomez, Andres; Benini, Luca. - In: SUSTAINABLE COMPUTING. - ISSN 2210-5379. - ELETTRONICO. - 2016:11(2016), pp. 38-49.
|Titolo:||InfiniTime: Multi-sensor wearable bracelet with human body harvesting|
|Autori:||Magno, Michele; Brunelli, Davide; Sigrist, Lukas; Andri, Renzo; Cavigelli, Lukas; Gomez, Andres; Benini, Luca|
|Titolo del periodico:||SUSTAINABLE COMPUTING|
|Anno di pubblicazione:||2016|
|Numero e parte del fascicolo:||11|
|Codice identificativo Scopus:||2-s2.0-84989852622|
|Codice identificativo ISI:||WOS:000389323400005|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.suscom.2016.05.003|
|Citazione:||InfiniTime: Multi-sensor wearable bracelet with human body harvesting / Magno, Michele; Brunelli, Davide; Sigrist, Lukas; Andri, Renzo; Cavigelli, Lukas; Gomez, Andres; Benini, Luca. - In: SUSTAINABLE COMPUTING. - ISSN 2210-5379. - ELETTRONICO. - 2016:11(2016), pp. 38-49.|
|Appare nelle tipologie:||03.1 Articolo su rivista (Journal article)|
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