Active stereo nose: Using air curtain to enhance the directivity

A new gas sensing system is proposed, which uses an actively generated air curtain to determine the direction of a gas source. The system is equipped with two gas sensors and two pumps. Air is sucked through two intake pipes, and is delivered to the left and right gas sensors to make lateral comparison of the gas concentration. The exhaust of the pumps is ejected backward from two pipes, and assist in collecting gas samples to the sensors. Unlike its predecessor, a part of the exhaust is guided to a flat nozzle to generate an air curtain with an appropriate shape and strength between the intake pipes. Experimental results are presented to show that the difference between the left and right sensor responses is effectively enhanced by the active generation of air currents. The direction of a gas source can be determined simply by comparing the left and right sensor responses.