DUST SENSOR AND AIR CLEANING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a dust sensor that can identify dust (allergen) and smoke (cigarette smoke), has a simple constitution, and low in price. SOLUTION: This dust sensor is constituted to detect the quantity of coarse particulates by projecting light upon the particulates from a pulse-driven light source 1 and detecting scattered light synchronized to a generated pulse and to identify the coarse particulates as dust when the difference between the maximum value and mean value of the output of a light receiving element 2 in a fixed period is larger than a prescribed value. This sensor is provided with an identifying means 5 which does not identify the coarse particulates as dust when the mean value in the subsequent fixed period is larger than a set value in the case where the difference between the maximum value and mean value of the output of the element 2 in the fixed period is larger than the prescribed value.