ULTRASONIC SNOW SENSOR AND SNOW MELTING DEVICE USING IT

摘要

PROBLEM TO BE SOLVED: To provide an ultrasonic snow sensor suitable to be used for a snow melting device, capable of detecting fallen snow with high reliability by avoiding wrong detection caused by an influence of the quality of the fallen snow.;SOLUTION: In addition to the first snow determination means for determining that snow has fallen when a measuring distance becomes short, compared with a reference distance in the state of no snow, the second snow determination means for determining that snow has fallen when a measuring distance becomes long is adopted. In order to stabilize furthermore snow determination, a wave receiving filter means wherein a recognition lower limit of an ultrasonic received signal level is set and a low-level received signal is not taken into consideration is adopted.;COPYRIGHT: (C)2007,JPO&INPIT