Research On Flexible Acoustic Sensor Based On PDMS-AgNWs

Acoustic sensors are widely used in life,industry,military and other fields because they can obtain the information of sound field.In recent years,with the development of flexible technology,the transformation of acoustic sensor from rigid structure to flexible structure has become a research hotspot at home and abroad.However,there is little research on the detection of sound source location using flexible acoustic sensors.Through the research on the current development of flexible acoustic sensors,it is found that the flexible acoustic sensors can obtain the information of sound field mainly using the change of the resistance of conductive nanomaterials under the acoustic signal vibration.The piezoresistive flexible strain sensor was studied,and the flexible devices were fabricated on PDMS as base and AgNWs as conductive nanomaterials.Firstly,the piezoresistive flexible strain sensor based on PDMS-AgNWs was prepared,its volt-ampere characteristics and tensile properties were tested,and a circuit was designed to convert resistance change into voltage change,which was applied in the sound field.The test results show that the piezoresistive flexible strain sensor based on PDMS-AgNWs has good conductivity and tensile properties,and can also be used for frequency detection in sound field.Then,the flexible acoustic sensor based on PDMS-AgNWs with a mass block-beam symmetrical structure was designed.The structure was optimized by a finite element software and the structural parameters were designed in combination with actual operation.The flexible acoustic sensor based on PDMS-AgNWs was prepared.A sound field test platform was set up to test the sound frequency,volume,sound field distance,resonance frequency of the device in the sound field,and the sensor was used for speech recognition.The results show that the prepared flexible acoustic sensor has a frequency detection range from 20 Hz to 2000 Hz,a volume detection range from 83 dB to 108 dB,a horizontal distance detection limit of 5 cm,a vertical distance detection limit of3.5cm,and an ability to distinguish.The resonant frequency of the device is380Hz.Finally,the sound source orientation was detected using the flexible acoustic sensor.In two-dimensional space,the flexible acoustic sensor was placed at different locations of the sound source,and?35?U/U₀ on the four beams were tested at each position.Through the analysis of the results,it can be seen that the flexible acoustic sensor can realize azimuth detection in a two-dimensional space,and the angle detection limit is 15°.In three-dimensional space,the flexible acoustic sensor array was designed by two flexible acoustic sensors to detect the position of the sound source.The detection of the three-dimensional sound source orientation can be achieved by comparing the?35?U/U₀ on the eight beams in the acoustic sensor array.