to ask what this this is?

[Penny325]

Just moved into a new home and wondering what this is? part of the fire alarm?

Maybe easier if you post a photo?

here is the photo

burglar alarm sensor i think.

Security alarm /motion detector

Motion detector for a burglar alarm

It’s a motion detector

how on earth would that be part of the fire alarm?!

Motion sector for a burglar alarm.

Even if there isn’t an alarm, people often leave them in place instead or removing and repairing

Where did you move from? Venus?

Yep motion sensor for a burglar alarm. We have one.

Even if you don't use the alarm, or the keypad had been taken out etc, and you are thinking of removing that sensor to make the room look 'tidier' then DON'T.

I made that mistake. They have little tiny springs coiled inside, or trigger switches, and if you remove them they assume they've been tampered with and the alarm starts going off and can't be switched off. At least not without an engineer. And I know this because in my first house I took a grotty faded one off the wall to check what type of connections a replacement would need. Miniscule tiny spring jumped out never to be seen again and as it was about 7pm on a Friday and I had moved to a new area my only option was to drive to the local pub down the the road and just shout to see if anyone was an electrician 🤣🤣 (in the days before Facebook when yellow pages was still a thing!).