Applicability of MEMS microphones for environmental sound level monitoring

2021 ◽  
Vol 263 (6) ◽  
pp. 875-885
Author(s):  
James Oatley ◽  
Craig Storey
Keyword(s):  
Integration Method ◽  
Sound Level ◽  
Monitoring Systems ◽  
Environmental Sound ◽  
Sound Localisation ◽  
Type Approval ◽  
Mems Microphone ◽  
Mems Technology ◽  
Mems Microphones ◽  
Level Monitoring

This paper explores the challenges associated with the integration of MEMS microphone technology into IEC 61672 classified or type-approved environmental sound level monitors. A comparison is drawn between MEMS microphones and electret condenser capsule microphones to highlight key performance differences within the technologies, and a basic integration method for both technologies is suggested. A review of the IEC 61672 and type-approval standards is conducted against the suggested integration method for a MEMS microphone; key shortcomings are reported and objectively reviewed. Development trends for MEMS microphones are explored, providing key insights into the progression of the technology against electret condenser capsule microphones. Furthermore, the evolution of environmental sound level monitoring systems is explored with a key focus on networked and sound localisation technology. The importance of MEMS microphones within the evolution of environmental sound level monitoring systems is presented alongside key arguments for the practical suitability of MEMS technology over electret condenser capsule technology.

An Alternate Geometry for a Piezoelectric MEMS Microphone, Part I: Design and Analysis

2007 ◽  
Author(s):  
Robert Littrell ◽  
Lei Cheng ◽  
Karl Grosh
Keyword(s):  
Microelectromechanical Systems ◽  
Complete Analysis ◽  
Noise Levels ◽  
Noise Characteristics ◽  
Mems Microphone ◽  
Mems Technology ◽  
Mems Microphones ◽  
Similar Materials ◽  
Piezoelectric Mems ◽  
Sensor Geometry

Microphones fabricated using microelectromechanical systems (MEMS) technology are one of the fastest growing applications of MEMS. While most commercial MEMS microphones are sensed capacitively, piezoelectric MEMS microphones require less accompanying electronics and offer increased linearity. Currently, piezoelectric MEMS microphones suffer from high noise levels, limiting their applicability. This paper presents an alternative sensor geometry consisting of a cantilever beam electrostatically clamped to the center of a diaphragm that both favorably concentrates stress from the applied acoustic load and eliminates the deleterious effects of residual stress in the piezoelectric material. A complete analysis of the sensitivity and noise characteristics of the electromechanical design (including the amplifying electronics) is performed and compared to a design employing a piezoelectric layer on a diaphragm. The analysis has shown that the proposed geometry can be used to build microphones sensed via aluminum nitride with noise levels around 48 dBA while similar materials and sizes result in noise levels around 57 dBA using the standard geometry.

MEMS microphone intensity array for cabin noise measurements

2021 ◽  
Vol 263 (3) ◽  
pp. 3023-3034
Author(s):  
Carsten Spehr ◽  
Daniel Ernst ◽  
Hans-Georg Raumer
Keyword(s):  
Sound Intensity ◽  
Phase Match ◽  
Acoustic Energy ◽  
Low Frequencies ◽  
Cabin Noise ◽  
Noise Simulation ◽  
Mems Microphone ◽  
Noise Measurements ◽  
Mems Microphones ◽  
Absorbing Material

Aircraft cabin noise measurements in flight are used toto quantify the noise level, and to identify the entry point of acoustic energy into the cabin. Sound intensity probes are the state-of-the-art measurement technique for this task. During measurements, additional sound absorbing material is used to ease the rather harsh acoustic measurement environment inside the cabin. In order to decrease the expensive in-flight measurement time, an intensity array approach was chosen. This intensity probe consists of 512 MEMS-Microphones. Depending on the frequency, these microphones can be combined as an array of hundreds of 3D- intensity probes. The acoustic velocity is estimated using a high order 3D finite difference stencil. At low frequencies, a larger spacing is used to reduce the requirement of accurate phase match of the microphone sensors. Measurements were conducted in the ground-based Dornier 728 cabin noise simulation as well as in-flight.

scholarly journals Using a Planar Array of MEMS Microphones to Obtain Acoustic Images of a Fan Matrix

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Lara del Val ◽  
Alberto Izquierdo ◽  
Juan José Villacorta ◽  
Luis Suárez
Keyword(s):  
Microelectromechanical Systems ◽  
Processing System ◽  
Signal Acquisition ◽  
Acoustic Images ◽  
Mems Microphone ◽  
The Matrix ◽  
Planar Array ◽  
Mems Microphones ◽  
The Individual ◽  
Signal Acquisition And Processing

This paper proposes the use of a signal acquisition and processing system based on an8×8planar array of MEMS (Microelectromechanical Systems) microphones to obtain acoustic images of a fan matrix. A3×3matrix of PC fans has been implemented to perform the study. Some tests to obtain the acoustic images of the individual fans and of the whole matrix have been defined and have been carried out inside an anechoic chamber. The nonstationary signals received by each MEMS microphone and their corresponding spectra have been analyzed, as well as the corresponding acoustic images. The analysis of the acoustic signals spectra reveals the resonance frequency of the individual fans. The obtained results reveal the feasibility of the proposed system to obtained acoustic images of a fan matrix and of its individual fans, in this last case, in order to estimate the real position of the fan inside the matrix.

Sound level monitoring apparatus

1982 ◽  
Vol 72 (3) ◽  
pp. 1095-1096
Author(s):  
Michael C. Martin ◽  
Ian R. Summers
Keyword(s):  
Sound Level ◽  
Level Monitoring

scholarly journals Towards the Interpretation of Sound Measurements from Smartphones Collected with Mobile Crowdsensing in the Healthcare Domain: An Experiment with Android Devices

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 170
Author(s):  
Robin Kraft ◽  
Manfred Reichert ◽  
Rüdiger Pryss
Keyword(s):  
Mobile Devices ◽  
Sound Level ◽  
Sensor Data ◽  
Environmental Sound ◽  
Mobile Crowdsensing ◽  
Sound Levels ◽  
Level Data ◽  
Combined Use ◽  
Smartphone Sensors ◽  
Ecological Momentary

The ubiquity of mobile devices fosters the combined use of ecological momentary assessments (EMA) and mobile crowdsensing (MCS) in the field of healthcare. This combination not only allows researchers to collect ecologically valid data, but also to use smartphone sensors to capture the context in which these data are collected. The TrackYourTinnitus (TYT) platform uses EMA to track users’ individual subjective tinnitus perception and MCS to capture an objective environmental sound level while the EMA questionnaire is filled in. However, the sound level data cannot be used directly among the different smartphones used by TYT users, since uncalibrated raw values are stored. This work describes an approach towards making these values comparable. In the described setting, the evaluation of sensor measurements from different smartphone users becomes increasingly prevalent. Therefore, the shown approach can be also considered as a more general solution as it not only shows how it helped to interpret TYT sound level data, but may also stimulate other researchers, especially those who need to interpret sensor data in a similar setting. Altogether, the approach will show that measuring sound levels with mobile devices is possible in healthcare scenarios, but there are many challenges to ensuring that the measured values are interpretable.

Using open source & low cost rain gauges to support debris flow real-time monitoring in Lima, Peru

2021 ◽  
Author(s):  
Miguel Arestegui ◽  
Miluska Ordoñez ◽  
Abel Cisneros ◽  
Giorgio Madueño ◽  
Cinthia Almeida ◽  
...  
Keyword(s):  
Debris Flow ◽  
Open Source ◽  
Historical Data ◽  
Low Cost ◽  
Monitoring Systems ◽  
Community Based ◽  
Rain Gauges ◽  
Flow Modelling ◽  
The One ◽  
Level Monitoring

<p>Debris flow, locally known as huaycos, impact the east part of the metropolitan city of Lima, capital of Peru. However, after many extreme events such as the one related to the 2017 “Coastal Niño” or the one in 1987, there is a lack of historical data and sufficiently accurate monitoring systems.</p><p> </p><p>The fact that this area is densely populated presents obvious challenges, from social and physical perspectives, but also some opportunities. We present our experience using open source & low cost rain gauges on previously unmonitored microwatershed, as part of a broader watershed-level monitoring system enhancement by SENAMHI (National Meteorological and Hydrological Service). We also present our experience on linking monitoring systems, debris flow modelling and community based risk management towards developing operational EWS.</p>

Effects of Sustained Exposure to Temperature and Humidity on the Reliability and Performance of MEMS Microphone

2017 ◽  
Author(s):  
Pradeep Lall ◽  
Amrit Abrol ◽  
David Locker
Keyword(s):  
High Temperature ◽  
Failure Modes ◽  
Sound Waves ◽  
Sensing Element ◽  
Operating Life ◽  
Reliability Data ◽  
Low Temperature Storage ◽  
Mems Microphone ◽  
Mems Microphones ◽  
Temperature Operating

MEMS microphones are extensively used in many applications that require reliability, small size, and high sound quality. For harsh environment reliability data MEMS microphones need to be monitored under conditions mimicking their areas of applications. MEMS microphones have an opening/sound port in order to interact with the environment, therefore cannot be sealed completely since the sensing mechanism requires interaction between sound waves and the sensing element. Little to no information exists on reliability data for MEMS microphones under low/high temperature operating life and temperature humidity bias condition. Our work is primarily focused on providing harsh environmental reliability data which can be useful to MEMS designers and engineers. In this paper the test vehicles with MEMS Microphones have been tested under three different harsh environmental conditions: high temperature operating life (HTOL) at 125°C at 3.3V, low temperature storage (LTS) at −35°C and temperature humidity 85°C/85%RH at 3.3V. The main motive of this study is to document the incremental shift and degradation in output parameters namely distortion, frequency response, power supply rejection capability of IC, frequency vs pressure characteristics and analog output voltage of the MEMS microphone. The survivability of MEMS microphone, ADMP401, has been demonstrated as a function of change in the output parameters. Failure analysis has been conducted on the microphone samples to study failure modes and sites using analytical methods such as SEM, EDS and X-ray.

Sign in / Sign up

Export Citation Format

Share Document