Hello.
I have some ZigBee devices connected via Xiaomi Gateway v2 to OH2.
I lost one of the devices (Aqara Motion Sensor). Don’t ask how. 
It’s probably in some drawer or closet. I can’t find it at all.
It still works, it is connected to OH2, and a few times a day it randomly detects movement. I set a rule to receive a notification on Telegram.
Any idea how I would find this sensor? Maybe with some RF Field Strength Meters? With which one?
I’m really curious where I stored it.
Thank.
I don’t know anything about this device, but if it’s registering movement, doesn’t it have to be able to see heat signatures? That would seem to rule out a drawer. However, if it isn’t going off all of the time, it can’t be in a high-traffic area. If you have pets, perhaps it can only see them.
I hate to bring up this possibility, but if it’s in a closet then it might be triggering due to mice/rats.
I don’t think an RF meter is going to do anything for you (or if that will even work), since your house is full of RF devices. You’re probably already on the right track with your telegram rule. You just have to search everywhere in your house and open everything until the rule triggers. Then you’ll know that you’re close.
I do use zigbee2mqtt thus don’t know how much of this your gateway supports…
In zigbee2mqtt, you have a map of the devices together with the link qualities between these. With this, you can check which zigbee routing device your sensor is currently connected to, also you could e.g. move a routing device (bulb, socket) to see wether link quality improves (i.e. you come closer) or it connects to a different routing device…
rfu
If it detects movement, I would connect to openhab on my phone an make sure I can see the status of the sensor. Then I would start walking around and look at my phone to see if it triggers. Mind you that it could be tha[ the vibration of people moving might cause the movement, so you might have to jump up and down 
Use
zigbee nodes
and
zigbee neighbors <IEEE Address of your lost sensor>
to narrow down its location.
Thank you all.
I doubt it’s mice, more likely a spider.
It’s been months since I’ve been able to find it. I’ve already looked everywhere.
Since I don’t have access to the sensor, I can’t connect it to another gateway. If i use zigbee2mqtt will i see this sensor too?
I have this binding Xiaomi Mi Smart Home - Bindings | openHAB
OH communicates with the gateway via wifi. OH dont have direct access to zigbee network.