The message
from David Hansen contains these words:

Provided the warm object is moving at more than the minimum speed
which the detector will detect. If the warm object is stationary or
moving slowly enough it will not be detected. That is why
sophisticated alarm systems tend not to use such sensors.

Because of the way the lens works it's very hard to move slowly enough
to not trigger the sensor. What does work is a thermal blanket. Even a
carboard sheild will work in most cases.

--
Skipweasel
Pay no attention to that man behind the curtain.