​Hi my name is Raveen Baloo from Singapore. Currently, I'm working on a project, building a case box which has a MCU and a LCD screen. A removable bluetooth dongle is connected to the case box which will allow users to connect and display a message on the LCD screen through an mobile app.

Now, on the other end of the dongle, there will be an audio jack. Users can remove the bluetooth dongle from the case box, and connect it to a radio or a walkman using the audio jack. Now, the user will be able to connect a bluetooth headphone with the bluetooth dongle. This upgrades the existing radio into a bluetooth enabled radio.

I have done some fair amount of research but I'm still new to bluetooth technology and having a lot of trouble. Here are some of the questions that i have:

1) Since its going to be a removable dongle, do i need a separate MCU with the dongle?

2) Will I be able to use standalone bluetooth audio module (RN-52)?

3) Is there a Bluetooth audio module while will be able to both act as a receiver and transmitter?

4) Will it be better just to have a separate in-built bluetooth in the case box itself or a separate MCU chip in the Bluetooth dongle?

5) Which Bluetooth module out there is the best for this project?

I really hope someone out there will be willing to help me out to clear some of my doubts or to direct me to some good materials out there on Bluetooth. Really hoping to hear from you guys. Feel free to ask me any question regarding this project.

Thanking in advance.


Raveen Baloo


closed as too broad by PeterJ, Daniel Grillo, nidhin, The Photon, brhans Feb 8 '16 at 2:15

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ Recommendations for a specific product are off topic. But Generally you need a bluetooth chip that can do serial (or other protocols) to talk to the lcd/mcu, and one that can do audio. Some of the BT audio chips can handle text/metadata to display on a lcd. AFAIK, there is no common/hobbyist bluetooth audio module that does both audio transmitting and receiving. \$\endgroup\$ – Passerby Feb 3 '16 at 19:46
  • \$\begingroup\$ @Passerby Thank you so much for clearing that up. This means, I need two Bluetooth module, one to handle the LCD, and the other Bluetooth module to handle the the audio transmission? \$\endgroup\$ – Raveen Baloo Feb 3 '16 at 19:52
  • \$\begingroup\$ Maybe. Depends on how you code and wire your setup. Like I said, I have a bluetooth audio device (Phone to BT to FM) that will see the music title from my phone on the device. There is a protocol for text data over the bt connection. A single bluetooth ic can do this. Maybe. \$\endgroup\$ – Passerby Feb 3 '16 at 19:55
  • \$\begingroup\$ You definitely shouldn't need two BTs. Through proper coding and parsing, you can handle audio and the LCD. \$\endgroup\$ – Vicente Cunha Feb 3 '16 at 19:57
  • \$\begingroup\$ @Passerby Thank you so much for the help. Guess I'll need to do more research. \$\endgroup\$ – Raveen Baloo Feb 3 '16 at 20:03

1) Yes, your BT dongle will require a MCU.

2) Sorry, didn't understand what you meant.

3) Bluetooth allows for communication in both ways, your only stress should be coding the MCU properly for your application.

4) This is a product design question and I definitely couldn't answer... depends on your product goals.

5) I would say one of your best options is to get a BT device that already comes with MCU. Check out this example part from bluegiga.

  • \$\begingroup\$ For the second question, there is a bluetooth module which does not require a mcu called RN-52. Still figuring out if its possible to use that bluetooth module for this project, but i don't think so. Thank you so much for your help. Will check that BT device from bluegiga and probably drop them an email. Thanks again :) \$\endgroup\$ – Raveen Baloo Feb 3 '16 at 20:07

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