All Meraki APs can "see" and locate Wi-Fi enabled devices even if these devices are not connected to your network. The only requirements are that the devices have their Wi-Fi feature turned on, and that your APs have the scanning feature turned on and integrated with your application.
If your APs are relatively new, they should support Bluetooth scanning alongside Wi-Fi scanning. Bluetooth scanning would let you see devices that:
- have both Wi-Fi and Bluetooth turned on
- have Wi-Fi turned off, but Bluetooth turned on
- do not support Wi-Fi, but support Bluetooth, and have it turned on (headphones, for example)
Given this, you could roughly approximate the number of people who have their Wi-Fi turned off by subtracting the number of devices seen through the Wi-Fi scanning system from the number of devices seen through the Bluetooth scanning system. For this to have any accuracy at all, you would have to assume that:
- every person has exactly one device on them
- every device that has Wi-Fi turned on also has Bluetooth supported and turned on.
These are pretty big assumptions.
If your question was about determining the number of people who have both Wi-Fi and Bluetooth turned off, that would not be possible using access points alone. Access points need devices to at least try to communicate in some way in order to see them. If a device has all of its radios turned off, it will be invisible to access points.
You could get cameras involved. This would get very expensive very fast, but if you position them in the right way you would be able to use the Sense API to count people in an area, and then have your application compare the number of people the cameras see to the number of devices your APs see.
Another alternative might involve beacons (also available on Android), although beacons can be very device- and vendor-specific.
Hope this helps, good luck!