IEEE Sensors Journal · 2014 · 131 citations · 17 references
EngineeringBioengineeringBiomedical EngineeringEnergy ManagementMicroelectromechanical SystemsSensorsBattery TechnologySensor NetworksSoft SensorsWearable Health TechnologiesWireless Power TransferWireless Sensor NetworksBiometric MonitoringEnergy HarvestingEnergy Harvesting DevicesPhysiological MonitoringPower ConsumptionSensor Node DesignSensor NodesWireless Sensor Node Design
Wearable wireless sensors are widely used for physiological monitoring, but their bulky, rigid designs and limited battery life hinder long‑term, body‑conforming deployment. This work introduces an autonomous, body‑conforming wireless sensor node that harvests energy flexibly for biometric monitoring. The node incorporates a flexible, ultralow‑power management circuit on a flexible PCB that efficiently transfers solar energy to a supercapacitor, enabling sustainable operation. The flexible PMC consumes only 32.86 µW, and under 320 lux indoor lighting the battery‑free node continuously measures and transmits temperature, generating 56 µW at a 30° body angle to sustain operation for over 15 h.
Distributed wearable wireless sensors are widely employed in wireless body sensor network for various physiological monitoring purposes like health or performance related monitoring applications. The real challenges in employing these wearable wireless sensors on human subjects include: 1) bulky and rigid system design thus, it is difficult to conform to human body contour and 2) limited operational lifespan of batteries with finite energy supply. In this paper, an autonomous body-worn wireless sensor node with flexible energy harvesting (FEH) mechanism, able to conform to body contour, is proposed for biometric monitoring. To be totally sustainable and compact, the FEH mechanism is equipped with an ultralow power management circuit (PMC) specially designed on a flexible PCB. The flexible PMC is able to transfer near maximum electrical power from the input solar energy source to store in the supercapacitor for powering the wireless sensor node. The power consumption of the flexible PMC is only 32.86 μW. Experimental results show that under indoor condition, typical average lighting intensity of 320 lux, the wearable sensor node is able to continuously monitor the temperature of the wearer, read, and transmit back to the base node in a wireless manner, without the need of any battery. In addition, the designed FEH sensor node flexed onto the wearer body contour at an angle of 30° generates 56 μW of electrical power, sufficient to sustain its operation for >15h.
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PV panel model based on datasheet values
Dezső Séra, Remus Teodorescu, Pedro Rodríguez · 2007 · 840 citations