Prototyping a wireless sensing platform for acoustic emission signals collected by microphone arrays

摘要

In this paper, we present a wireless sensing prototype for condition monitoring using acoustic emission signals. It consists of a 4-member microphone array, a 4-channel 16-bit analog-to-digital converter (ADC) and a wireless node. The prototype will serve as a platform for sensor and algorithm developments for gearbox condition monitoring. In the TinyOS operation system, software interfaces are written in the nesC language to link the hardware with high-level programs. The prototype will eventually collect acoustic emission signals from the microphone array, convert them into digital data using the ADC, perform local signal processing and transmit the results to another wireless node or a base station. Two TinyOS programs are also written to test the functionality of the ADC and the wireless nodes. The programs also demonstrate that data collection and transmission for the one-channel case has been accomplished, though the four-channel case is still under development. Preliminary results and analysis are presented in the paper. Future improvements would involve microphone array filtering/denoising, four-channel data transfer, signal processing and decision making algorithms, and a high-level wireless transmission protocol.