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I live in a rented apartment, and there is this little plastic box on the wall that I had been ignoring. Here is what it looks like:

enter image description here

There are no markings or holes on the casing. I got curious and opened it up, and was surprised to find a small PCB inside:

the circuit board

Since it's about halfway up the wall, I was thinking it could be a carbon monoxide detector, but those are usually pretty identifiable or at least have some holes on the side. I was also thinking it could be a wireless doorbell, but we don't have one of those, nor do I see any evidence that there was one here previously. Any ideas?

mostsquares
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2 Answers2

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It's a temperature sensor w/ wireless transmitter:

https://www.inovonics.com/products/dual-input-temperature-transmitter-en1723/

I found that by googling the various numbers printed on the stickers -- EN1723 turned the device up as the top hit.

Nate S.
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It's basically a remote thermometer which sends the room temperature to a 'heat computer', which in turn turns the heat (or a/c) on or off based on settings comparing it with the other units in the building. Turning the screws will do nothing. They are used to attach another temperature sensor for transmission. The receiver/'heat computer' will detect and display a low battery message and the sensor will show as missing if the battery is dead or the unit is removed from the building (out of range). The units run about $75 or so, be prepared to pay for replacement if you remove it and/or toss it out. If you wish to try to 'fool' the sensor readings, put an incandescent lamp or other heat source under it to show a higher temperature, it's a little harder to show a lower temperature, maybe a small ziplock bag with ice? hanging above it? Be careful not to get it wet though!

Paul
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