I've been doing some research into the various ways of communicating with a microcontroller using bluetooth. I understand how to set up the pc side by using a usb bluetooth dongle as a serial port, but I'm having a bit of trouble finding what I would like to know about the micro controller connection.
I noticed in the bluetooth tutorial it says that one way of doing this is to buy an rs232 to bluetooth converter and plug it into the serial port of the microcontroller. I also saw in the UART tutorial that you can use a USB to UART converter that allows you to create a serial link between your pc and microcontroller using a standard USB cable. What I would like to know is can you add a USB to UART converter to your microcontroller, then plug a USB dongle into this? Effectively replacing a USB to USB cable with two USB bluetooth dongles.
If this is not possible, why are you able to connect to a bluetooth to rs232 addaptor but not a bluetooth to USB addaptor, when they are both connected to the UART pins? Is it only USB that has the issues of defining a "host" and "device"?
I hope I've managed to state my question clearly. The reason I'm looking to connect using this method is that it seems to be much cheaper to buy usb bluetooth dongles than it is to buy bluetooth rs232 dongles, or bluetooth UART modules. I'm also just curious about both USB and bluetooth interfaces.