I am currently deciding whether it would be best to maintain an active bluetooth connection, use an rf system, or have a system where when a condition is met a central Bluetooth device(battery consumption doesn’t matter on this one) receives data from many other Bluetooth devices(battery matters for these). In the third option I would have the central device send a signal that tells the other devices to broadcast.
I don’t really have an idea for what would be the most efficient signal or if the voltage required to maintain a receiver on the others would consume too much power. For this third option would it make more sense to use rf?
Also I only need at most 4m of range.
For my purposes rfid will not work.