Bluetooth module help?

Question

Hello,

I have done some work with Bluetooth modules in the past and have connected them to microcontrollers. However, I am still unclear as to what the best module for my applications is. My main point of confusion lies in whether or not a "profile stack" is needed for simple data connections.

For example, I can purchase a $70 module with built in SPP (Serial Port Profile) or a $60 module without it. With the $70 module, hook-up is fairly straigh forward. Just talk to the module over UART/Serial. If, however, I go with the cheaper module, how much more work do I have to do in the microcontroller to talk to the module? I'm sure this is somewhat module-specific, but in general, how necessary is the "profile stack"? Is it worth the extra $10?

Thank you very much for your comments.

Best Regards, Adam Kumpf snipped-for-privacy@mit.edu

Here are the two modules for comparison:

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(look at the 2nd module and the 6th module )

Thanks again. :)

Martin Maurer · Accepted Answer

Hello,depends if it is a private project or a commercial project. And on the amount of pieces you want to produce. If it is commercial, you need a Bluetooth certification for your developed parts (Bluetooth stack), which is not cheap. Also a lot interop test are needed, if you want to be compatible. You already have an Bluetooth tester (Air Sniffer, HCI decoder...) ? Most important, also take into account the time (and amount of people) needed to write such a stack.If private project, you can just take the modules, create a ACL connection and transfer some data. But this way is not compatible to anything else !Perhaps, to make your decision easier, download the Bluetooth Core Spec. and have a look at chapters HCI, L2CAP, RFCOMM. All these are needed to implement your Serial Port Profile...If yu have further questions you can contact me directly via email !Regards,        Martin

Adam Kumpf · Answer

Thanks so much for the reply.It sounds like $10 is a pretty small price to pay for greatlysimplifying the design of a proof-of-concept prototype.  The time andcost required to implement my own HCI, L2CAP, and RFCOMM for abluetooth project is probably not worth it unless I end up wanting toproduce millions of these gadgets.Your input was very helpful!Thanks again,  Adam

Anton Erasmus · Answer

Unless you want to use these modules in huge quantities, $10 is peanuts to pay for the software stack. Also remember that the production cost for the manufacturer is essentially 0 for this software over time. So over time and with the competition one would expect they would drop this extra $10. Just for interest sake, which modules are you considering ?

Regards Anton Erasmus

Bluetooth module help?

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