The Mobile Acoustic Array Robot Sensor (MAARS) project is an array of three equally spaced audio microphones in a triangular plane that detects sound sources from any direction to use in mobile robot navigation and line of sight sensor pointing. It is an acoustic sensor that provides non line of sight detection of audio signal sources.
Individual beams are formed digitally by the delay and add method using a computed table of sample time offset factors. The microphones are an omni directional design made with off the shelf parts. Each of the three analog microphone signals is digitized by an Atmel ATmega16 microprocessor to form a digital beam in a particular direction. The beam signals can be band pass filtered to pass specific frequencies such as human speech or mechanical sounds. The beam angles are used to point a pan tilt platform with other sensors such as a camera in the audio source direction.
“The entire sensor fits within a nine inch sphere, weighs under a half pound, and mounts on a remote controlled mobile robot. Compared to vision and range sensors, robot audition capability is in its infancy,” said Henry Pfister, project designer.