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

The use of digital microfluidics for a silicon photonic sensors platform

status: publishe

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

19–22 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