Here's how you do this:
In dude, go to "Functions" and create a new function called: wireless_clients
under "Code" paste in the following:
array_size(oid_column("iso.org.dod.internet.private.enterprises.mikrotik.mikrotikExperimentalModule.mtXRouterOs.mtxrWireless.mtxrWlRtabTable.mtxrWlRtabEntry.mtxrWlRtabStrength"))
click on Ok and go back to your network map
right click on one of your wireless devices and select "Appearance"
click on the "Label" box and paste the following:
[Device.Name]
[device_performance()][Device.ServicesDown][wireless_clients()] Wireless Clients
Click on Ok and see your handy work.
Here's to graph it:
Right click on your network object and go to "Settings"
on the "Services" tab, add a new service
click on the 3 dots next to "Probe"
Fill out the following settings:
Name: wireless_probe
type: Function
Available: wireless_clients()
Error: if(wireless_clients(), "", "")
Value: wireless_clients()
Unit: Clients
rate: None
click on "ok" and select the wireless_probe as your probe
Hit Ok again and you should be graphing the number of wireless clients now.
Cheers
Edit: Added to the wiki:
http://wiki.mikrotik.com/wiki/Number_of ... ss_Clients