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🔌General Home Automation => Automating Your House => Troubleshooting Automation Problems => Topic started by: PettyKash on July 05, 2011, 08:46:43 PM

Title: MS14A inside a window?
Post by: PettyKash on July 05, 2011, 08:46:43 PM
Has anyone had success using a MS14A motion sensor from inside a window?

I have tried parallel with the window, and at a 45-degree rotation.

The chime will work when my fingers are between the sensor and window, but reacts to nothing outside the window.

The sun is not reflecting into the sensor.
Title: Re: MS14A inside a window?
Post by: JMac on July 05, 2011, 09:13:33 PM
You need to research how these work.  They don't react to "motion", but instead react to a heat differential.
Title: Re: MS14A inside a window?
Post by: dbemowsk on July 05, 2011, 09:27:59 PM
The MS14A uses an infrared sensor that reacts to heat.  I am betting that the infrared sensor is getting confused by the window glass.  Some parts of the infrared spectrum will pass through glass, but others won't.  Other factors come into play also, like the type of windows they are (single or double pane), tinting of the glass (if any), and other light being reflected inside the glass.  The sun may not be directly reflecting into the sensor, but there is probably a slight bit that is bouncing around in there causing heat that is confusing it.  In short, I wouldn't trust it behind glass.
Title: Re: MS14A inside a window?
Post by: dave w on July 06, 2011, 10:21:34 AM
Just jumping on this band wagon.

They do not work through glass (MS14, MS16, DS10, etc. or any motion detector that uses moving infrared light as a trigger). As Dan pointed out, glass filters out most of the infrared light. I do not know if a polycarbonate window pane (Plexiglas, Lexan, etc) would pass infrared light any better, but suspect not.

Can you mount the MS14A outside the glass?
Title: Re: MS14A inside a window?
Post by: PettyKash on July 06, 2011, 10:34:20 AM
Ok, thanks for the responses.