motion detector, sense motion through window?

[fat freddy]

I have a utility room I want to protect, which has a large window and glass door.  I have the door and window contact switches installed but wanted to add a motion detector in case entry is gained by breaking the window.

I don't want the motion detector to be set off by movement outside the room, only inside.  Problem is, the best spot to mount the motion detector is opposite the door and window.  Will the motion detector "see" through the glass?

Thanks.

- Fat Freddy

[Don N]

Not sure which motion sensor you have but, my experience with the MS14A motion sensor ... they do not allow detection through glass.  The MS14A measures the heat difference in the surrounding area and therefore will not detect that heat difference through glass.  I do not have any experience with other motion sensors.  Try checking out the X10 KowledgeBase for more information.  http://kbase.x10.com/wiki/Motion_Sensors

[fat freddy]

Thanks.  The knowledge base does not address the question, but I suppose all I have to do is try it!

[FromDimension12]

FF:

Most window glass attenuates infrared radiation substantially. By using one of the relatively insensitive X10 indoor motion detectors, you should have little or no problem with activation by outdoor heat sources. Also, you could adjust the central aiming point downward to reduce pickup of outdoor motion, if needed.

However, a simpler approach might be to use a glass break detector on the window instead of a motion detector in the room. This could be wired in series with the existing magnetic contact circuit. USP (United Security Products) has an inexpensive glass break detector called the Window Bug.

My suggestion is that you use a low cost glass break detector on the window and forget about using a motion detector.

In cases where outdoor motion detection is desired, then the wise approach is to install an outdoor detector.

Advice From Beyond

[vhoang]

I've had no success actually wanting detection through a window.  Tried with a MS14A, MS16A, DS10A with no detection at all.  But it could just be my window.   

[HA Dave]

Will the motion detector "see" through the glass?

I placed a eagle-eye motion sensor (at my daughter's apartment) between the glass windowed entrance door, and the glass windowed storm door.

Because the motion sensor can't "see" through the glass, neither her movements inside, or passer-bys can be detected. However, now she never has to enter a dark home, as a light is turned on before she can even get a key in the (entrance) door.

As an added bonus, if anyone attempts to tamper with the door (at night) a light will come on. And, when it gets dark another (separate) light automatically comes on.

[dave w]

I placed a eagle-eye motion sensor (at my daughter's apartment) between the glass windowed entrance door, and the glass windowed storm door.

Because the motion sensor can't "see" through the glass, neither her movements inside, or passer-bys can be detected. However, now she never has to enter a dark home, as a light is turned on before she can even get a key in the (entrance) door.

GREAT IDEA!!! Thanks!