Sound direction recognition using a condenser microphone array

This paper presents a sound direction recognition system for intelligent mobile robots. We studied the analysis, design, and circuit realization of a standalone sound recognition system using multiple condenser microphones. Sound signals from three condenser microphones are integrated in a circuit to resolve the source direction. The minimum recognition angle of a triangular configuration is derived. A new decode method is proposed in this paper to resolve the sound direction. The proposed scheme uses a circuit to obtain direction information, an improvement to the conventional computer-based approaches. The recognition circuitry has been implemented using UMC 0.5μm IC chip fabrication technology. Both simulation and practical experiments validate the desired performance. Experimental results show that the system recognizes sound direction with an accuracy of ±5°. The sound recognition system has been integrated to a multi-robot system to investigate various robot control applications using whistle sound in a noisy environment. Experimental results demonstrate the effectiveness of the proposed method.