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.