Hmmm... interesting. How would that work? Just count the number of BT signals in a room?

How many BT devices is the average student or faculty member toting around with them at a given point?

Could conceivably be 4+ with some combination of: phone, smartwatch, tablet, BT speaker, game device, etc.

The idea is to scan every minutes for BLE MAC Addresses and send to a backend. On the backend you can identify what is the manufacturer of every MAC addresses and make some correlation. A very simple idea is to filter only the phone MAC addresses and use as presence counter estimator; it's a bit unlikely that a university student will have more than one phone.

A better method would try to correlate not random MAC addresses (headphones, BLE trackers, wearebles, etc) that are frequently together and mark as a single person.