Sherrerd: Paranoid much?!
My guess: CO detector
I hope someone comes back in here and tells us what that is!
They live.
It’s the IR controller for that grid ball thing.
It is an infrared diffused mode wireless transmitter. It is a member of INNCOMs Integrated Room Automation System (IRAS). Most commonly, it is used as a wireless door switch transmitter to report door open and close status to the e4 digital thermostat.
Here is a website for the item S541
I was going for the laugh.
(Of course the NSA does get up to quite a lot, whether we laugh or not.)
Looks like CWN got it.
Here’s a google image search:
That’s it!
My faith in the 'Dope has been restored.
I was beginning to worry, because it seems that whenever someone has a “What is this?” question the answer comes within five minutes, in quadruplicate. This one took a little longer.
Next time I’m up there I’ll take out my phone and look for IR signals coming from it when I open the door. If I can see flashes, I’ll snap a picture and post it.
ETA: Now that we know what it is, I see someone else was asking about the mystery object on their blog.
Well, here I am on my monthly trip to Connecticut.
First thing I did after settling down was to inspect the S541 device.
I put my iPhone in “selfie mode” and used the front camera to monitor the device as I opened the door.
A glance at the thermostat showed that the top left corner is black, obviously where a IR receiver is listening for those invisible door signals.
Yay! Closure. 
And upon opening too.
So, that’s the “Official” story on what they’re used for. What do you think the NSA really uses them for?
If the sensors are on a wireless circuit, I presume that, for real, the signals could be intercepted and an outline/heat profile of anyone/thing could be reconstructed.
What are the infrared probe frequency/strength requirements for that?
groan
Well done.
Care to explain how this would work?