TY - JOUR

T1 - Optical Wake-Up From Power-Off State for Autonomous Sensor Nodes

AU - Dudko, Uliana

AU - Overmeyer, Ludger

N1 - Funding Information: Manuscript received June 4, 2020; revised August 2, 2020 and September 3, 2020; accepted September 8, 2020. Date of publication September 14, 2020; date of current version January 6, 2021. This work was financially supported by the Lower Saxony Ministry for Science and Culture (Germany) within the framework of the Tailored Light Project. The associate editor coordinating the review of this article and approving it for publication was Dr. Yongjia Li. (Corresponding author: Uliana Dudko.) The authors are with the Institute of Transport and Automation Technology, Leibniz Universität Hannover, 30823 Garbsen, Germany (e-mail: uliana.dudko@ita.uni-hannover.de; ludger.overmeyer@ita.uni-hannover.de). Digital Object Identifier 10.1109/JSEN.2020.3023817

PY - 2021/2/1

Y1 - 2021/2/1

N2 - Wireless sensor nodes spend most of their time in standby mode and wake up periodically to send measurement data. Typically, a radio-frequency antenna is coupled with an amplifier to provide this wake-up function; together, these two elements recognize instances of radio signal activation. Even during standby operation, the sensor node utilizes a certain base amount of energy, which can be critical when using an energy-harvesting source. In this study, we propose a novel optical approach to the wake-up function for autonomous sensor nodes, which employs a solar cell as the wake-up signal detector. A bright light flash coming from another node or a smartphone hits a solar cell and activates the sensor node. Unlike photodiodes or RF-antennas, solar cells do not require any additional energy to detect such a signal. Therefore, the proposed electrical circuit allows the sensor node to wake-up from a complete power-off state. The solar cell of the novel wake-up receiver has an area of sensitivity of 8 mm ×10 mm. The wake-up signal can be recognized from a maximum distance of 25 cm at a range of ambient illumination from 0-1600 lx with a transmitter optical power of 20 mW. In the power-off state, the power consumption of this novel design is the lowest of all existing off-the-shelf wake-up receivers: 248 pW at 0 lx and 627 nW at 1600 lx.

AB - Wireless sensor nodes spend most of their time in standby mode and wake up periodically to send measurement data. Typically, a radio-frequency antenna is coupled with an amplifier to provide this wake-up function; together, these two elements recognize instances of radio signal activation. Even during standby operation, the sensor node utilizes a certain base amount of energy, which can be critical when using an energy-harvesting source. In this study, we propose a novel optical approach to the wake-up function for autonomous sensor nodes, which employs a solar cell as the wake-up signal detector. A bright light flash coming from another node or a smartphone hits a solar cell and activates the sensor node. Unlike photodiodes or RF-antennas, solar cells do not require any additional energy to detect such a signal. Therefore, the proposed electrical circuit allows the sensor node to wake-up from a complete power-off state. The solar cell of the novel wake-up receiver has an area of sensitivity of 8 mm ×10 mm. The wake-up signal can be recognized from a maximum distance of 25 cm at a range of ambient illumination from 0-1600 lx with a transmitter optical power of 20 mW. In the power-off state, the power consumption of this novel design is the lowest of all existing off-the-shelf wake-up receivers: 248 pW at 0 lx and 627 nW at 1600 lx.

KW - eess.SP

KW - Wireless sensor networks

KW - autonomous sensors

KW - optical wireless communication

KW - energy harvesting

KW - wake-up receiver

KW - visible light communication

KW - solar cell

UR - http://www.scopus.com/inward/record.url?scp=85099205121&partnerID=8YFLogxK

U2 - 10.1109/JSEN.2020.3023817

DO - 10.1109/JSEN.2020.3023817

M3 - Article

VL - 21

SP - 3225

EP - 3232

JO - IEEE Sensors Journal

JF - IEEE Sensors Journal

SN - 1530-437X

IS - 3

M1 - 9195495

ER -