163 research outputs found
Characterisation of an Electrostatic Vibration Harvester
Harvesting energy from ambient vibration is proposed as an alternative to
storage based power supplies for autonomous systems. The system presented
converts the mechanical energy of a vibration into electrical energy by means
of a variable capacitor, which is polarized by an electret. A lumped element
model is used to study the generator and design a prototype. The device has
been micromachined in silicon, based on a two-wafer process. The prototype was
successfully tested, both using an external polarization source and an
electret.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/EDA-Publishing
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
A 3D Ferrite Coil Receiver for Wireless Power Supply of Endoscopic Capsules
AbstractTo expand capsular endoscopy from a mere passive screening tool towards a multipurpose robot, batteries become inadequate. Wireless power supply overcomes the problem of power shortage allowing the integration of high power demanding modules. This work focuses on wireless inductive power transfer and its optimization in size and materials. The ongoing development on 3D coil geometries is further refined by the introduction of a laser machined ferrite core to boost the amount of available power. It is demonstrated that 330mW can be transferred to a capsule under all possible orientations, within a 0.63cm3 volume
Motion-Based Generators for Industrial Applications
Scaling down of electronic systems has generated a large interest in the
research on miniature energy sources. In this paper a closer look is given to
the use of vibration based scavengers in industrial environments, where waste
energy is abundantly available as engine related vibrations or large amplitude
motions. The modeling of mechanical generators resulted in the design and
realization of two prototypes, based on electromagnetic and electrostatic
conversion of energy. Although the prototypes are not yet optimized against
size and efficiency, a power of 0.3 mW has been generated in a 5 Hz motion with
a 0.5 meter amplitude.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Design and fabrication of a low cost implantable bladder pressure monitor
In the frame of the Flemish Community funded project Bioflex we developed and fabricated an implant for short term (< 7 days) bladder pressure monitoring, and diagnosis of incontinence. This implant is soft and flexible to prevent damaging the bladder's inner wall. It contains a standard flexible electronic circuit connected to a battery, which are embedded in surface treated silicone to enhance the biocompatibility and prevent salt deposition. This article describes the fabrication of the pill and the results of preliminary cytotoxicity tests. The electronic design and its tests, implantation and the result of the in-vivo experimentation will be presented in other articles
Electrostatic microgenerators
Accepted versio
<Session 3: Biomedical Technology>Assessing radio frequency electromagnetic field exposure with a wearable network of dosimeters
19â22 May 2022 Kyoto, JapanIn contrast to the tremendous increase of wireless applications, the knowledge about daily life radio frequency electromagnetic field (RF-EMF) exposure remains low. Some research has already been conducted using large commercial single-antenna on-body dosimeters to assess daily RF-EMF exposure in different environments. To increase measurement quality and decrease variability however, a distributed, wearable body sensor network spread over the body for the assessment of RF-EMF exposure is desired. As a better alternative to the common single node assessment technique, this work therefore presents a wearable sensor network consisting of five nodes for the assessment of exposure in the 389 to 464, 779 to 950 and 2400 to 2483.5MHz bands using only two transceivers per node. A single node supports an antenna connection for the first band, two for the second and two for the third band. This makes antenna diversity possible and hence increases sensitivity for specific frequencies, depending on the choice of antenna design. Every node is powered by two AAA batteries, which define the size of the system (53x25x15mm), making it smaller than any other commercially available dosimeter. Furthermore, the device supports an inertial sensor for the assessment of body posture and/or activity during the measurement
Micropatterning and dynamic swelling of photo-crosslinkable electroactive Pluronic hydrogel
AbstractThis paper presents the controlled swelling of a novel combination of materials for microsystems: a photopatternable electroactive polymer gel. It is very promising as an actuator material for e.g. biomedical or microfluidic applications as it shows a volume swelling of over 50% upon application of very modest voltages in a liquid environment. We present the synthesis of the novel material, the development of a MEMS compatible fabrication process and the measurements on fabricated test structures
Ring resonator based SOI biosensors
In this paper, two recent advances in silicon ring resonator biosensors are presented. First, we address the problem that due to the high index contrast, small deviations from perfect symmetry lift the degeneracy of the normal resonator mode. This severely deteriorates the quality of the output signal. To address this, we discuss an integrated interferometric approach to give access to the unsplit, high-quality normal modes of the microring resonator. Second, we demonstrate how digital microfluidics can be used for effective fluid delivery to nanophotonic microring resonator sensors fully constructed in SOI
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