| Outstanding write-up! We actually built a business based on this technology (occuspace.io) and have had to address almost all the questions that you brought up. To answer some of them here: Q: How accurate is BLE beacon count, as a proxy for occupancy? A: It's very highly correlated but different dining locations, classrooms and library floors have very different correlation factors. Consider using other, perhaps more complex features, as well. Q: How accurate is BLE beacon availability time, as a proxy for dwell time? A: We don't believe it is very accurate given that BT MAC's randomize every 8-20 mins depending on manufacturer. Q: Can we improve the accuracy by setting an RSSI minimum, for which devices weaker than it do not count, to ensure only those who are really nearby get counted? A: That's a great idea. It's worth noting that different types of spaces and depending on where you installed your sensor, will have different threshold levels. |
But how often is an accurate count needed? The initial requirement of the project was just for the OP to "avoid crowds in the dining hall", and for that all one needs is a general idea of highs and lows.
In your business, do customers expect high accuracy? All of them, or some of them?
Also, regarding MAC address, even if they're randomized, isn't there a way to know what kind of device it is? (to count only phones for example, and discard headphones, etc.)