| 摘要 |
The device is provided with independent range finding means 10-13 and movement sensing means 14-16, the sensing means generating output signals in response to the detection of an object, which output signals provide information as to the range and size of the object detected, and a comparator means for comparing the output signal from the sensing means with a pre-set threshold level. The range finding means is preferably ultrasonic while the movement sensing means may be a PIR sensor or a microwave Doppler sensor. |
