Help tracking if a device is disconnected

Howdy guys!,

this message is regarding a project that I want to start ,

i work at a hotel and they have roku systems at the tvs,
but the thing is that the guests keep stealing the rokus and we want to make trought home assistant a process that can detect a roku that gets disconnected for more than 24 hours, and send an email to check for it .

our network is managed by ubiquiti so I assume that we can use the ubiquiti device tracker but my principal concerns are:

  1. discover only rokus devices at hassio i dont know if there is a way to get manufacturer information from device tracker
  2. when it gets discover i can send an email after 24 hours of beign disconnected how to achieve that

Any help would be appreciated!,

How big is the hotel?
If this is a modest size then you could use Ping sensors manually setup to ping every 5 minutes to see if attached.
There is also a Roku integration but you would need the IP addresses for those just like the ping sensor.
As for email there is an SMTP integration to allow sending of email.
I would name the ping sensors for the room they are in and then make an automation with conditions of pings being offline for your 24 hours.
I would also have a display that lists all the roku devices, which is by far the easiest to do. As long as you name your ping sensors with reasonable logic you can display all your rokus and their status; have it sort by status and color code the state and you very easily see what is offline. This is what I do on my own network.

Thanks for your help!, it helped me to develop a different automation with some speakers systems that I have around the hotel.

So basically it has to be with the IP address?

Because i would like to get the devices scanning a MAC address range and add it automatically, is it possible?