So I have not actually experimented with the HC05 Bluetooth Module yet, but I have read up about it and watched some videos. From what I understand, you cannot use one module (master) to communicate with more than one other module (slaves), or at least its pretty difficult. But, you can use a module hooked up to an arduino to communicate to to another module hooked up to another arduino (I believe pretty simply).
However, I thought it might be possible to use an Arduino Mega (because it has multiple TX/RX pins) with 3 HC05 Bluetooth modules, to each communicate to 3 separate HC05s which would each be hooked up to an arduino nano. I know this might have to do something with running multiple Software Serials (I have no idea what that is to be honest)?
The project involves using the master arduino to "listen" for a button pressed on the slave arduino (across the room without connecting wires), then listening for another button press from one of the other slaves in some sort of sequence and within a certain time frame.
Does anyone have any idea about how this might be done, even if it doesn't use the HC05 Bluetooth Module?