Monitoring of Physiological Sounds with Wearable Device based on Piezoelectric MEMS Acoustic Sensor

2021 ◽  
Author(s):  
Mengjiao Qu ◽  
Xuying Chen ◽  
Dengfei Yang ◽  
Dongsheng Li ◽  
Ke Zhu ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Myocardial Contraction ◽  
Low Noise ◽  
The Body ◽  
Wearable Device ◽  
Acoustic Sensor ◽  
Human Machine Interaction ◽  
Vocal Fold Vibration ◽  
Mechanical Waves ◽  
Silicone Polymers

Abstract Physiological mechano-acoustic signals play a pivotal role in medical diagnosis and fitness monitoring. Mechanical waves generated by natural physiological activities such as myocardial contraction, and vocal fold vibration, propagate through the tissues and fluids of the body and reveal characteristic signals of these events. Conventional methods such as stethoscope and electrocardiography (ECG) are not suitable for wearable mode and continuous monitoring. In this paper, we propose a wearable physiological sounds sensing device to monitor heart sound and detect speech and voice with high accuracy. The device consists of a MEMS (microelectromechanical systems) acoustic sensor and a low-noise amplification circuit, and both of them are packaged by silicone polymers with an air cavity to achieve conformal contact with human skin. The proposed device has advantages of light weight, sweatproof capability, resistant to noise and good stability. The wearable device has great potential in clinical diagnosis, healthcare, human-machine interaction and many other applications.

scholarly journals A High Efficiency Low Noise RF-to-DC Converter Employing Gm-Boosting Envelope Detector and Offset Canceled Latch Comparator

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Thi Thuy Pham ◽  
Dongmin Kim ◽  
Seo-Hyeong Jeong ◽  
Junghyup Lee ◽  
Donggu Im
Keyword(s):  
Power Consumption ◽  
High Efficiency ◽  
Supply Voltage ◽  
Current Source ◽  
Low Noise ◽  
The Body ◽  
Common Source ◽  
Conversion Gain ◽  
Input Transistor ◽  
Envelope Detector

This work presents a high efficiency RF-to-DC conversion circuit composed of an LC-CL balun-based Gm-boosting envelope detector, a low noise baseband amplifier, and an offset canceled latch comparator. It was designed to have high sensitivity with low power consumption for wake-up receiver (WuRx) applications. The proposed envelope detector is based on a fully integrated inductively degenerated common-source amplifier with a series gate inductor. The LC-CL balun circuit is merged with the core of the envelope detector by sharing the on-chip gate and source inductors. The proposed technique doubles the transconductance of the input transistor of the envelope detector without any extra power consumption because the gate and source voltage on the input transistor operates in a differential mode. This results in a higher RF-to-DC conversion gain. In order to improve the sensitivity of the wake-up radio, the DC offset of the latch comparator circuit is canceled by controlling the body bias voltage of a pair of differential input transistors through a binary-weighted current source cell. In addition, the hysteresis characteristic is implemented in order to avoid unstable operation by the large noise at the compared signal. The hysteresis window is programmable by changing the channel width of the latch transistor. The low noise baseband amplifier amplifies the output signal of the envelope detector and transfers it into the comparator circuit with low noise. For the 2.4 GHz WuRx, the proposed envelope detector with no external matching components shows the simulated conversion gain of about 16.79 V/V when the input power is around the sensitivity of −60 dBm, and this is 1.7 times higher than that of the conventional envelope detector with the same current and load. The proposed RF-to-DC conversion circuit (WuRx) achieves a sensitivity of about −65.4 dBm based on 45% to 55% duty, dissipating a power of 22 μW from a 1.2 V supply voltage.

Abstract 156: Involvement of β-adrenergic System in Myocardial Dysfunction Induced by Obesity

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Ana Paula Lima-Leopoldo ◽  
Artur Ferron ◽  
Bruno Jacobsen ◽  
Dijon Campos ◽  
Renata Luvizotto ◽  
...  
Keyword(s):  
Myocardial Dysfunction ◽  
Myocardial Contraction ◽  
Experimental Models ◽  
The Body ◽  
Adrenergic System ◽  
Standard Diet ◽  
Adrenergic Stimulation ◽  
High Fat ◽  
Functional Changes ◽  
Adiposity Index

Several structural and functional changes of the heart have often been associated with human and experimental models of obesity. Some factors have been suggested as responsible for possible cardiac abnormalities in models of obesity, among them β-adrenergic system, an important mechanism of regulation of myocardial contraction and relaxation. The objetive of present study was to evaluate the . Thirty-day-old male Wistar rats were assigned to one of two groups: control (C) and obese (Ob). The C group was fed a standard diet and Ob group was fed cycles of four unsaturated high-fat diets for 15 weeks. The body fat was measured from the sum of the individual fat pad weights and the obesity was defined by adiposity index. Isolated papillary muscle preparation was performed under basal conditions and after inotropic and lusitropic maneuvers. β-adrenergic system was evaluated by using cumulative concentrations of isoproterenol and Western Blot. After 15 weeks, the Ob rats developed higher adiposity index than C rats. Obesity promoted comorbities such as glucose intolerance, insulin resistance, hyperleptinemia, and dyslipidemia; however, were not associated with changes in systolic blood pressure. The cardiac structure results post-death showed that obesity caused cardiac hypertrophy. Furthermore, Ob muscles developed similar baseline data, but myocardial responsiveness to post-rest contraction stimulus and increased extracellular Ca2+ was compromised. There were no changes in cardiac function between groups after β-adrenergic stimulation. The obesity was not accompanied by changes in protein expression of Gsα, β1 and β2 adrenergic receptors. In conclusion, the myorcardial dysfunction caused by unsaturated high-fat diet-induced obesity, after 15 weeks, is not related to β-adrenergic system impairment.

scholarly journals A High Q-Factor Outer-Frame-Anchor Gyroscope Operating at First Resonant Mode

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1071
Author(s):  
Bo Jiang ◽  
Yan Su ◽  
Guowen Liu ◽  
Lemin Zhang ◽  
Fumin Liu
Keyword(s):  
High Performance ◽  
Microelectromechanical Systems ◽  
Resonant Mode ◽  
Low Noise ◽  
Silicon On Insulator ◽  
Q Factor ◽  
Wafer Level ◽  
High Q ◽  
Ring Structures ◽  
Static Performance

Disc gyroscope manufactured through microelectromechanical systems (MEMS) fabrication processes becomes one of the most critical solutions for achieving high performance. Some reported novel disc constructions acquire good performance in bias instability, scale factor nonlinearity, etc. However, antivibration characteristics are also important for the devices, especially in engineering applications. For multi-ring structures with central anchors, the out-of-plane motions are in the first few modes, easily excited within the vibration environment. The paper presents a multi-ring gyro with good dynamic characteristics, operating at the first resonant mode. The design helps obtain better static performance and antivibration characteristics with anchor points outside of the multi-ring resonator. According to harmonic experiments, the nearest interference mode is located at 30,311 Hz, whose frequency difference is 72.8% far away from working modes. The structures were fabricated with silicon on insulator (SOI) processes and wafer-level vacuum packaging, where the asymmetry is 780 ppm as the frequency splits. The gyro also obtains a high Q-factor. The measured value at 0.15 Pa was 162 k, which makes the structure have sizeable mechanical sensitivity and low noise.

scholarly journals Compact Acoustic Rainbow Trapping in a Bioinspired Spiral Array of Graded Locally Resonant Metamaterials

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 788 ◽  
Author(s):  
Liuxian Zhao ◽  
Shengxi Zhou
Keyword(s):  
Health Monitoring ◽  
Microelectromechanical Systems ◽  
Acoustic Wave Propagation ◽  
Spiral Tube ◽  
Helmholtz Resonators ◽  
Frequency Selection ◽  
Mechanical Waves ◽  
Space Saving ◽  
Spiral Array ◽  
Sub Wavelength

Acoustic rainbow trappers, based on frequency selective structures with graded geometries and/or properties, can filter mechanical waves spectrally and spatially to reduce noise and interference in receivers. These structures are especially useful as passive, always-on sensors in applications such as structural health monitoring. For devices that face space and weight constraints, such as microelectromechanical systems (MEMS) transducers and artificial cochleae, the rainbow trapping structures must be compact as well. To address this requirement, we investigated the frequency selection properties of a space-saving design consisting of Helmholtz resonators arranged at sub-wavelength intervals along a cochlear-inspired spiral tube. The height of the Helmholtz resonators was varied gradually, which induced bandgap formation at different frequencies along the length of the spiral tube. Numerical simulations and experimental measurements of acoustic wave propagation through the structure showed that frequencies in the range of 1–10 kHz were transmitted to different extents along the spiral tube. These rainbow trapping results were achieved with a footprint that was up to 70 times smaller than the previous structures operating at similar bandwidths, and the channels are 2.5 times of the previous structures operating at similar bandwidths.

Self-Assisted Care System for Human Mobility

2004 ◽  
Vol 16 (5) ◽  
pp. 464-472
Author(s):  
Teruhisa Onishi ◽  
◽  
Tatsuo Arai ◽  
Kenji Inoue ◽  
Yasushi Mae ◽  
...  
Keyword(s):  
Human Body ◽  
Human Mobility ◽  
The Body ◽  
Wearable Device ◽  
End Effector ◽  
Sitting Posture ◽  
Holding Device ◽  
Physically Challenged ◽  
Care System

Since humans are bipedal, it is easy to become bedridden when the hip and legs become weakened or disabled due to aging or other causes. If such physically challenged people are enabled to get up from bed and move to a nearby location, however, they could use their arms and hands to do certain tasks such as taking meals or writing. In this paper, we propose a wearable device for supporting the human body that can be easily worn or removed by means of a body-holding device. The hoisting device has an arm which, as an end-effector, supports the body and allows the user to rise from bed and lie down again. In addition, a three-point fixing mechanism is used to maintain the user’s sitting posture at a desk, and to realize an integrated self-assisted care system.

Microelectromechanical systems directional acoustic sensor for underwater applications

2019 ◽  
Vol 146 (4) ◽  
pp. 2996-2996
Author(s):  
Jason Roberts ◽  
Alberto Espinoza ◽  
Fabio Alves ◽  
Renato Rabelo ◽  
Gamani Karunasiri
Keyword(s):  
Microelectromechanical Systems ◽  
Acoustic Sensor

scholarly journals A Sporting Chance

2011 ◽  
Vol 133 (07) ◽  
pp. 40-45
Author(s):  
Noel C. Perkins ◽  
Kevin King ◽  
Ryan McGinnis ◽  
Jessandra Hough
Keyword(s):  
Inertial Measurement Unit ◽  
Wireless Sensors ◽  
Microelectromechanical Systems ◽  
Angular Rate ◽  
Rigid Body Dynamics ◽  
The Body ◽  
Measurement Unit ◽  
Golf Club ◽  
Sports Training ◽  
Inertial Measurement

This article discusses using wireless sensors to improve sports training. One example of wireless sensors is inertial sensors that were first developed for automotive and military applications. They are tiny accelerometers and angular rate gyros that can be combined to form a complete inertial measurement unit. An inertial measurement unit (IMU) detects the three-dimensional motion of a body in space by sensing the acceleration of one point on the body as well as the angular velocity of the body. When this small, but rugged device is mounted on or embedded within sports gear, such as the shaft of a golf club, the IMU provides the essential data needed to resolve the motion of that equipment. This technology—and sound use of the theory of rigid body dynamics—is now being developed and commercialized as the ingredients in new sports training systems. It won’t be too long before microelectromechanical systems based hardware and sophisticated software combine to enable athletes at any level to get world-class training.

scholarly journals Stretchable Composite Acoustic Transducer for Wearable Monitoring of Vital Signs

2019 ◽  
Author(s):  
Yasin Cotur ◽  
Michael Kasimatis ◽  
Matti Kaisti ◽  
Selin Olenik ◽  
Charis Georgiou ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Vital Signs ◽  
The Body ◽  
Sound Waves ◽  
Acoustic Transducers ◽  
Acoustic Transducer ◽  
Silicone Polymers ◽  
Initial Results ◽  
Soft Composite

AbstractWe report a highly flexible, stretchable, and mechanically robust low-cost soft composite consisting of silicone polymers and water (or hydrogels). When combined with conventional acoustic transducers, the materials reported enable high performance real-time monitoring of heart and respiratory patterns over layers of clothing (or furry skin of animals) without the need for direct contact with the skin. Our approach enables an entirely new method of fabrication that involves encapsulation of water and hydrogels with silicones and exploits the ability of sound waves to travel through the body. The system proposed outperforms commercial, metal-based stethoscopes for the auscultation of the heart when worn over clothing and is less susceptible to motion artefacts. We have tested the system both with human and furry animal subjects (i.e. dogs), primarily focusing on monitoring the heart, however, we also present initial results on monitoring breathing. Our work is especially important because it is the first demonstration of a stretchable sensor that is suitable for use with furry animals and do not require shaving of the animal for data acquisition.

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