Scan for connected devices in same Wifi

Hi,

a great feature would be getting a list of connected devices (IP/Mac) within the same Wifi as the phone.

Apps like "Fing" can display this information, so it should be possible without root. Sadly I didn't find an app that can send this information to tasker.

Why I want this:
I want to make a task to turn off all lights, when nobody is at home. I could do this via geofencing with the Hue app, but it draines a lot of battery on the older iPhone of my gf. (Also no Tasker on her phone to send a message if she disconnects from home Wifi)

Do what I want to do is: have an old Huawei P7 scanning the network every x minutes and if none of the two phones (MAC-Adresses) is connected, turn off the lights. (This also would turn them off at night)

So any possibility of adding this to one of the apps?

 

around 3 sec to get all devices, around 10 to get the names, too.

But when trying this I just noticed that the iPhone disconnects from wifi everytime the screen goes off; googling says that there's no way of changing this on iOS.
I really hate, she's using this "we know best what you need and won't give you a choice"-OS. (It's my third idea on how to track the home state that's not working because of iOS)

So maybe it's nice for others I imagine, but probably I won't be able to use it....