Three Microphones Embedded System for Single Unknown Sound Source Localization

This paper presents an embedded system for localizing a sound source in a two-dimensional plane. It uses an ensemble of three microphones placed in a straight line, and a digital signal processor for capturing and processing the signals. The controller is equipped on a development board, along with a display which shows the calculated results. The signal processing consists of a slightly modified Cross Correlation method used to obtain the delays of arrival of the three microphone signals. To obtain the distance and angle, inversed mathematical equations were used, determined in Matlab from the geometric direct equations. The obtained results show a minimal error for short distances and the error increases when the distance between the sound source and the microphones gets bigger. A large distance also shows some flaws in obtaining the right time delays, thus some erroneous results can be observed. This is caused by the limited power of the speaker used for tests, but also by the environmental noise and the reverberations. The system could be improved by using a faster approach for extracting the time delay information from the signals