787 research outputs found
Bioelectronic Sensor Nodes for Internet of Bodies
Energy-efficient sensing with Physically-secure communication for bio-sensors
on, around and within the Human Body is a major area of research today for
development of low-cost healthcare, enabling continuous monitoring and/or
secure, perpetual operation. These devices, when used as a network of nodes
form the Internet of Bodies (IoB), which poses certain challenges including
stringent resource constraints (power/area/computation/memory), simultaneous
sensing and communication, and security vulnerabilities as evidenced by the DHS
and FDA advisories. One other major challenge is to find an efficient on-body
energy harvesting method to support the sensing, communication, and security
sub-modules. Due to the limitations in the harvested amount of energy, we
require reduction of energy consumed per unit information, making the use of
in-sensor analytics/processing imperative. In this paper, we review the
challenges and opportunities in low-power sensing, processing and
communication, with possible powering modalities for future bio-sensor nodes.
Specifically, we analyze, compare and contrast (a) different sensing mechanisms
such as voltage/current domain vs time-domain, (b) low-power, secure
communication modalities including wireless techniques and human-body
communication, and (c) different powering techniques for both wearable devices
and implants.Comment: 30 pages, 5 Figures. This is a pre-print version of the article which
has been accepted for Publication in Volume 25 of the Annual Review of
Biomedical Engineering (2023). Only Personal Use is Permitte
Low power CMOS IC, biosensor and wireless power transfer techniques for wireless sensor network application
The emerging field of wireless sensor network (WSN) is receiving great attention due to the interest in healthcare. Traditional battery-powered devices suffer from large size, weight and secondary replacement surgery after the battery life-time which is often not desired, especially for an implantable application. Thus an energy harvesting method needs to be investigated. In addition to energy harvesting, the sensor network needs to be low power to extend the wireless power transfer distance and meet the regulation on RF power exposed to human tissue (specific absorption ratio). Also, miniature sensor integration is another challenge since most of the commercial sensors have rigid form or have a bulky size. The objective of this thesis is to provide solutions to the aforementioned challenges
Hybrid Energy Harvester for Medical Sensor Node toward Real-Time Healthcare Monitoring
In healthcare applications, the remote monitoring for moving patients depends on medical sensor nodes, which should be mobile. Thus, the power mains of medical sensor nodes should be disconnected most of the time to monitor natural movements of patients. In this paper, a self-sustainable medical sensor node is proposed for healthcare monitoring applications. The node implementation consists of a microcontroller unit (MCU), a photo-plethysmography (PPG) sensor, a Bluetooth low energy (BLE) module, and a MPU module that includes a gyroscope with accelerometer. The power supply of the node is a hybrid energy harvester developed to provide a sustainable energy for the sensor node. The harvester is composed of a photovoltaic (PV) panel, a thermoelectric generator (TEG) module, a DC-DC converter, and a super-capacitor. Experimental results illustrate that the proposed node can monitor a physiological data on a mobile device using the BLE Terminal application
Millimeter-Scale and Energy-Efficient RF Wireless System
This dissertation focuses on energy-efficient RF wireless system with millimeter-scale dimension, expanding the potential use cases of millimeter-scale computing devices. It is challenging to develop RF wireless system in such constrained space. First, millimeter-sized antennae are electrically-small, resulting in low antenna efficiency. Second, their energy source is very limited due to the small battery and/or energy harvester. Third, it is required to eliminate most or all off-chip devices to further reduce system dimension. In this dissertation, these challenges are explored and analyzed, and new methods are proposed to solve them. Three prototype RF systems were implemented for demonstration and verification. The first prototype is a 10 cubic-mm inductive-coupled radio system that can be implanted through a syringe, aimed at healthcare applications with constrained space. The second prototype is a 3x3x3 mm far-field 915MHz radio system with 20-meter NLOS range in indoor environment. The third prototype is a low-power BLE transmitter using 3.5x3.5 mm planar loop antenna, enabling millimeter-scale sensors to connect with ubiquitous IoT BLE-compliant devices. The work presented in this dissertation improves use cases of millimeter-scale computers by presenting new methods for improving energy efficiency of wireless radio system with extremely small dimensions. The impact is significant in the age of IoT when everything will be connected in daily life.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/147686/1/yaoshi_1.pd
A new power MEMS component with variable capacitance
Autonomous devices such as wireless sensors and sensor networks need a long battery lifetime in a small volume. Incorporating micro-power generators based on ambient energy increases the lifetime of these systems while reducing the volume. This paper describes a new approach to the conversion of mechanical energy, available in vibrations, to electrical energy. The conversion principle is based on charge transportation between two parallel capacitors. An electret is used to polarize the device. A large-signal model was developed, allowing simulations of the behavior of the generator. A small-signal model was then derived in order to quantify the output power as a function of the design parameters. These models show the possibility of generating up to 40 muW with a device of 10 mm 2. A layout was made based on a standard SOI-technology, available in an MPW. With this design a power of 1 muW at 1020 Hz is expected
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