A Flexible, Acoustic Localized Sensor with Mass Block–Beam Structure Based on Polydimethylsiloxane–Silver Nanowires

The flexible strain sensor is a fast-moving technology and has been used in many fields. The array design and application based on flexible strain sensors have been the current research hotspots. However, there are few reports on research of acoustic positioning using the flexible sensor array. Herein, we designed and realized the consistent fabrication of a thin-film, acoustic sensor array. The acoustic sensing research of the sensor was demonstrated as well. We used a convenient fabrication method to design a flexible acoustic sensor using silver nanowires coated on a thin polydimethylsiloxane (PDMS) film with mass block-beam structure. The acoustic sensor can record sound within a frequency domain of 20-2000 Hz and volume detection range of 83-108 dB. The sensor's resonance frequency is 380 Hz, horizontal distance sound detection limit is 5 cm, and vertical detection limit is 3.5 cm. We also achieved 360° azimuth detection in two-dimensional space with a detection accuracy of 15°. In three-dimensional space, the flexible acoustic sensor array was designed with two flexible acoustic sensors to detect the position of the sound source. This research first proposes the use of flexible acoustic sensors to test the sound source orientation.