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This paper presents the development of tactile sensors using the sol-gel process to deposit a PZT thin-film from 250 nm to 1 μm on a flexible stainless steel substrate. The PZT thin-film tactile sensor can be used to measure human pulses from several areas, including carotid, brachial, finger, ankle, radial artery, and the apical region. Flexible PZT(More)
Piezoelectric transformers (PTs) converters show some difficulties to work in the case of the variable load at fixed frequency. PTs can be designed to achieve these problems, but the size of the PT may become larger. In fact, the selection of the circuit topologies and the control methods influence the size and the efficiency of the PT converter. Two(More)
An innovative, multilayer piezoelectric transformer equipped with a full modal filtering input electrode is reported herein. This modal-shaped electrode, based on the orthogonal property of structural vibration modes, is characterized by full modal filtering to ensure that only the desired vibration mode is excited during operation. The newly developed(More)
A composite optical bend loss sensor for measuring 3-D forces has been developed. The sensor is composed of two optic fiber meshes which are embedded into a polydimethylsiloxane (PDMS) slab. The sensor consists of an array of optical fibers lying in perpendicular rows and columns sandwiched inside an elastomeric pad. A map of normal and shear stress is(More)
This paper focuses on comparing the effects of varying degrees of electromechanical coupling in piezoelectric power harvesting systems on the dynamics of charging a storage capacitor. In order to gain an understanding of the behavior of these dynamics, a transducer whose vibrational dynamics are impacted very little by electrical energy extraction is(More)
A high-precision ultrasonic ranging system platform is presented and evaluated in this work. By queuing peaks of the self-destructive interference, the proposed hardware platform can enhance the accuracy without complex algorithms. At the emitter, the developed technique generates two amplitude-modulated pulses with 180° phase shift. At the receiver,(More)
With the rapid development of low power consumption electronics, wireless sensor networks (WSN) are highly investigated and used to improve our life quality. Using piezoelectric materials to transfer the mechanical energy into electrical energy for batteries of WSN in order to extend the life time is the focus in many researches in the recent years. It is(More)
Piezoelectric transformers (PT) are widely adopted in recent year due to many advantages, including safety, no EMI problem, low housing profile, and high power density, etc. The characteristics of the PT are well-known when the load impedance is a pure resistor. When PTs are used in AC/DC or DC/DC converters, there are always a rectifier circuit block(More)
In this paper, a low cost and low power consumption humidity sensor was developed by blending SiO<sub>2</sub> nano-particles blending with PEDOT conductive polymers. The developed sensing material was fabricated by inkjet-printing technology on silicon substrate. Compared with pristine PEDOT:PSS materials, the adding of SiO<sub>2</sub> nano-particles(More)
This work demonstrates a printable blending material, i.e., reduced graphene oxide (RGO) mixed with poly(methyl methacrylate) (PMMA), for formaldehyde sensing. Based on experimental results, 2% RGO/10% PMMA is an optimal ratio for formaldehyde detection, which produced a 30.5% resistance variation in response to 1000 ppm formaldehyde and high selectivity(More)