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Which parts for receiving/sending audio over bluetooth ?

Former Member

Hello Forum,

I'm an electronical engineering student  and i have to build a project for my final exam. I have decided to build circuit that receices audio from a smartphone (or any other BT device if it's possible) and puts it out as an analog signal ( so that you can plug it over a cable into an amplifier or into a cars radio). I want to begin this project this summer and have to finish it until 14 June next year.

Now i don't know which IC's or uC i have to use. If I have enough time i want to build the transmittig part to, so that i don't have to use my phone and can plug any other device with an aux exit.

 

What are the parts that you would recommend me ?

 

My mother language is german so im sorry for grammar mistakes image

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  • Hello Simon,

     

    This seems an odd subject for your project - you can buy such things ready made and very cheaply from dozens of different sources - what new feature are you going to add ?

     

    As for chips try Google:  bluetooth audio receiver chip

     

    You'll find lots of chips - your biggest problem will be finding one that you can buy, that has adequate documentation and is in a package you can solder to a board.

     

    Michael Kellett

  • in reply to michaelkellett

    Hello Michael,

    thank you for you quick response.

    So you think this is not a good project ? It may be better if try making a small fm transmitter that sends my audio from mp3 direct to the radio ? i know that this is illegal but i wont make a transmitter that has a lot of watts. I would only make it with a half watt or something like this.

    I know that there is a lot of stuff like this already finished and ready to buy, but i thought it would be a nice project :/

    You think that the idea with the fm transmitter would be better ?

    I maybe already found an IC that would fit for modulation (stereo fm transmitter BH1415F) .http://www.mikrocontroller.net/attachment/24717/BH1415F.pdf


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  • in reply to michaelkellett

    Hello Michael,

    thank you for you quick response.

    So you think this is not a good project ? It may be better if try making a small fm transmitter that sends my audio from mp3 direct to the radio ? i know that this is illegal but i wont make a transmitter that has a lot of watts. I would only make it with a half watt or something like this.

    I know that there is a lot of stuff like this already finished and ready to buy, but i thought it would be a nice project :/

    You think that the idea with the fm transmitter would be better ?

    I maybe already found an IC that would fit for modulation (stereo fm transmitter BH1415F) .http://www.mikrocontroller.net/attachment/24717/BH1415F.pdf


Children
  • in reply to Former Member

    Hello Simon,

     

    You need to do a lot more reading and thinking about the project. You need to KNOW if it's legal - It's a common duty of  a professional engineer to advise on compliance with regulations. If you build a half watt transmitter operating in the normal FM band expect to do time in gaol (or community service if you are lucky). I think half a milli Watt might be too much for this application. Legal unlicensed radio usually uses power in the range 1-10mW.

    If the leagl issues are OK then the FM based project would be good because you will be able to do all the work yourself. Bluetooth is so complicated that you will end up using huge chunks of pre-built software and  hardware that you won't understand (not least because the suppliers don't document it.).

     

    So by all means do the MP3 to car radio by FM link (if it's legal) but approach it like a professional project and make sure you understand the theory, regulations, customer requirements (your college ?) etc.

     

    Michael Kellett

  • in reply to michaelkellett

    Hello Michael,

     

    it is legal up to a few 10 nW, but is this power enough to reach your cars antenna ? doesnt the cars body work like a faradaysch cage ? do you maybe know for which law i must search to know the exact nW that i can use? I already did a little bit of reasearch on this topic and found out that in germany you can use up to 50nW if im not wrong. But like it always is in italy there are different laws then in every other country.

    This project will just work as a prototype and will not go in any production.

    Do you think i should make it discret or just use an IC ? It must not be an amazaningly complicated project because others are also only making not to hard things, for example a radio clock.