Bluetooth HC-06 or Otherwise

hi all
this my first post and I look forward to learning a thing or ten…
I am a Design Tech teacher and have a Year12 student who wishes to make a Bluetooth key station that would monitor and house 4 sets of keys (house, cars etc). The idea is that the ‘station’ serves as a place where keys are returned and kept when family members come home. Works a bit like this -

  1. when keys are within bluetooth range they are expected to be stored in station otherwise there is a constant beep or similar. allowing for a time duration when keys are leaving bluetooth range or coming back into bluetooth range etc.

each key set would be attached to its own ‘keyring unit’. there would be a single receiver in the home station.

i think m y question is 'how many bluetooth connections can a HC-06 or 05 handle? Would she need a separate receiver unit in home station for each keyring unit?
OR is there a better way to solve this problem?? The student is in a Year 12 Design Technology class.
It occurs to me as i’m writing this that maybe a wireless/bluetooth setup using an ESP8266 or ESP32 plus some HC-05/06’s may work. I really dont know but am keen tohelp her pursue the idea. I am quite familiar with arduino now but i havent used any of the bluetooth type technologies yet.

Many thanks for the opportunity and hoping to get some ideas
regards Scott

Hi Scott,

This is a bit outside of my area of expertise as well, but it should be possible using bluetooth 4.0 and BLE devices. I found this library for use:

It’s got a nice primer for bluetooth in it, and in one section they describe the “bulletin board” method that you should be able to use for this project. The HC-05/6 is a simple bridge and can only really be used for single device to single device.

This might be a good platform to use as your base. It’s very well documented:

I hope that helps!