What is the easiest and cheapest way to determine the occupied rooms in a building in real time, taking into account who exactly?

Question

Do it yourself

It is understood that only predetermined people can be in the building. Their names are known, and they all agree to assist in the creation of such a surveillance system (even if it is known who and how often goes to the toilet, and how much time they spend there, and with whom).

But at the same time, it must be taken into account that all of them are people, that is, they can forget, make mistakes, and make random decisions every day that cannot be predicted in advance. That is, the scheduling option is not suitable.

We also exclude the option "to go and see who is where", because it is not cheap. The beholder needs to eat a lot, and sometimes sleep. This includes the option of creating a security service that watches everyone through cameras. The reason is the same - it is expensive and difficult, and is usually used specifically for security, i.e. definitions of whowhat does. But we don’t need this information at all (moreover, unnecessary questions about privacy will arise, despite the fact that a priori no one feels sorry for revealing only their location within the building).

Answer 1

Try RFID tags. They are really made for this purpose.
Each zone-room can be covered with antennas and thus register people with their badges and others. There are solutions for offices, warehouses and open spaces. Not only control of finding people, but also property.

Answer 2

ACS is in your hands.
Another option is mikrotik + carpsman + a plate in every room.
Each set up an access point on the phone. By the logs of the entrance, you determine who and where.
You can even draw a map.

Answer 3

ACS is designed to solve this problem. RFID readers for entering and exiting the room, an electric lock on the door, an access controller, plus, if you need to know exactly where a person is currently outside the rooms, divide the floors into sections with doors with locks and readers. Or the entrances to the floors. Tags at first will be forgotten and lost, then they will get used to wearing them. Distribute to everyone with roulettes on carbines. I would look towards the Russian manufacturer Era.