I recently moved to Aerohive NG and they provide an excellent API to monitor your devices. I have been in contact with Check MK and they have provided me with an mkp file that most likely will be availible for everyone soon. To set up this do the following.
Start by creating an account at https://developer.aerohive.com
Create an APP and write down the info. You will need this later
Download and install hivemanager_ng-1.1.mkp
You can now create a dummy host like below.
Now open the ruleset and enter the info you got from your app. You will also need to know the Aerohive ID.
Create a rule to warn you about the connected levels.
It will now show up like this.
Note that in the basic plan your API calls are limited. It might be a good idea not to check every minute.