公开(公告)号：US20040129883A1

公开(公告)日：2004-07-08

申请号：US10338531

申请日：2003-01-08

Applicant: Home Data Source

Inventor： Brian C. Dougherty ,  Robert M. Bunch ,  Rachel E. Lukens ,  James Nagel ,  Christopher L. Wolfe

IPC: G01J005/00

CPC classification number: G08B13/191 ,  G01J5/34 ,  Y10S250/01

Abstract: A passive low power device for detection of boundary crossings includes a dual element pyro-electric infrared (PIR) sensor. The sensor is designed with a lens that provides a very narrow field of view and two pyro-electric elements that produce a waveform with two voltage swings of opposite polarity when a warm object moves past the sensor. The waveform is filtered and amplified before it is passed on to a comparator. The comparator triggers off the extremes of each waveform. The comparator includes two outputs that are normally high, but go low when a change in infrared radiation is detected. A processor makes an approximation of the zero crossing time based on the rising edge of the first comparator output. This approximate zero crossing time serves as an estimate of the boundary crossing time.

Abstract translation: 用于检测边界交叉的无源低功率设备包括双元件热电红外（PIR）传感器。 传感器设计有一个提供非常窄的视野的透镜和两个热电元件，当暖物体移动通过传感器时，产生具有相反极性的两个电压摆幅的波形。 波形在通过比较器之前被滤波和放大。 比较器触发每个波形的极值。 比较器包括通常为高的两个输出，但是当检测到红外辐射的变化时，该输出变低。 处理器基于第一比较器输出的上升沿来近似于过零时间。 这个近似的零交叉时间作为边界交叉时间的估计。