Using USB bluetooth dongle to mbed

18 Sep 2012

Hi everyone,

For my project, it involves using an off-the-shelf USB bluetooth dongle ($3) to communicate with my LPC1768 mbed through USB (pin31, pin32). My ultimate goal is to hopefully be able to communicate my Android phone with the mbed using bluetooth. But for now I'm having trouble working out the configuration with the dongle and the mbed. I've looked at some libraries such as BlueUSB (http://mbed.org/users/peterbarrett1967/notebook/blueusb---bluetooth-and-usb-host-controller-for-mb/) and and being a novice of bluetooth programming, the codes are not making sense to me. If anyone could point me in the direction where I can begin on how to program bluetooth using USB that would be great.

I've also seen other projects using UART serial communication for bluetooth and I'm actually more comfortable using UART. But in your opinions, would a project of this scope be better suited for USB or UART? Or are these two communications the same thing? Please correct me if I'm wrong.

Thanks in advance.

18 Sep 2012

Hi Jonathan,

I used the RN41 module to communicate over Bluetooth which I think would be a lot easier than writing a Bluetooth library. Details can be found here

Good luck Martin

18 Sep 2012

Hi Jonathan,

Forget about BlueUSB and Android you will not go far with this combination for many reasons. Just to give you some more important is that: BlueUSB is not complete proper Bluetooth stack and your communication with Android will be fail very soon or will not happen ever. The second reason is that even if BlueUSB will be modified in order to support proper timing of the Bluetooth protocol stack in all layers from HCI, L2CAP and RFCOMM you still need to add your code with so careful implementation that it will not affect your BlueUSB Bluetooth communication stack. Which mean probably the only way to make it work correctly is to go and make it work with RTOS. So BlueUSB in RTOS + your code there. Finally if you success with this you will see your power consumption will go away very quickly.

From my point of view it is much better to use dedicated Bluetooth chip like this BlueCore4-Ext which is used in RN41 , RN42 and etc. The RN41 and RN42 are expensive, so probably it is better to use something like this http://www.dealextreme.com/p/wireless-bluetooth-rs232-ttl-transceiver-module-80711 which cost 6,6$ and if you do not like it Bluetooth firmware then upgraded it to the firmware which I am provided here in http://www.uelectronix.com My firmware have probably the best in market Bluetooth stack for RFCOMM communication and the low power consumption for it.

So maybe help you little bit and good luck with your project.

Kind Regards, Stas