Solar Energy Harvesting to Improve Capabilities of Wearable Devices Articles uri icon

publication date

  • May 2022

start page

  • 3950

end page

  • 3971

issue

  • 10

volume

  • 22

International Standard Serial Number (ISSN)

  • 1424-3210

Electronic International Standard Serial Number (EISSN)

  • 1424-8220

abstract

  • The market of wearable devices has been growing over the past decades. Smart wearables
    are usually part of IoT (Internet of things) systems and include many functionalities such as
    physiological sensors, processing units and wireless communications, that are useful in fields like
    healthcare, activity tracking and sports, among others. The number of functions that wearables
    have are increasing all the time. This result in an increase in power consumption and more frequent
    recharges of the battery. A good option to solve this problem is using energy harvesting so that the
    energy available in the environment is used as a backup power source. In this paper, an energy
    harvesting system for solar energy with a flexible battery, a semi-flexible solar harvester module and
    a BLE (Bluetooth® Low Energy) microprocessor module is presented as a proof-of-concept for the
    future integration of solar energy harvesting in a real wearable smart device. The designed device
    was tested under different circumstances to estimate the increase in battery lifetime during common
    daily routines. For this purpose, a procedure for testing energy harvesting solutions, based on solar
    energy, in wearable devices has been proposed. The main result obtained is that the device could
    permanently work if the solar cells received a significant amount of direct sunlight for 6 h every day.
    Moreover, in real-life scenarios, the device was able to generate a minimum and a maximum power
    of 27.8 mW and 159.1 mW, respectively. For the wearable system selected, Bindi, the dynamic tests
    emulating daily routines has provided increases in the state of charge from 19% (winter cloudy days,
    4 solar cells) to 53% (spring sunny days, 2 solar cells).
    Keywords: energy harvesting; internet of things; physiological

subjects

  • Electronics

keywords

  • energy harvesting; internet of things; physiological sensors; solar energy; wearables; wireless communication; wireless sensor network