Well that sucks. (Arduino Stereo Part 2)

Well I received my RN-52, got it all soldered up, and hooked up to my laptop for the initial setup. Once I figured out that I needed to hit enter after entering a command, I got everything set to start streaming music from my phone.

Fantastic. Wait, the sound quality is kind of… wrong. I check the connections to the trrs breakout, everything looks good. Nope. Wait a moment. Flip the connections around. That’s better. Not fantastic though. And now the Bluetooth chip is flaking out if I run at full volume. Perhaps my power supply isn’t running enough current to the chip. No, that’s not it. I eventually gave up on that and tried test calls to see if the audio was OK. Unfortunately not. I have no audio coming through the microphone. Well tits.

So after a couple months with it just sitting there, I noticed that Sparkfun released a new bluetooth chip. The BC127. So I ordered that. When that one arrived, I did the same thing. Soldered everything up, wired it up to the computer, set everything to start streaming music. Fantastic, this one doesn’t crash when I run it at full volume. However, the audio quality isn’t as good as the RN-52. That’s fine, I’ll build an equalizer or something, but at this point, that’s far into the future. And this chip also passes the MP3 metadata through serial. Great, so now I can display the track information on a screen. Fantastic.

When I try to make a call, however, I get the same problem. There is no audio coming through the microphone. This time I did a little more research. I found out that I’m not building the circuit correctly, and I need to put a few more components between the microphone and the chip. Balls. And I can’t for the life of me figure out what I’m missing. I’ve picked up an electret microphone with a built in amplifier, but it’s not working either. This is seriously pissing me off now. Doing a search for electret microphone biasing returns so many different results depending on what you are attempting to do, that I can’t make heads or tails of it.

So I’ve put the project on hold while I learn more circuit building. We’ll see if I can figure this out eventually. If not, I have two chips to build a music box out of.

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About Skullnerd

I could tell you how long I've been on the internet, but I don't remember, or care. I could tell you that I love food, but I don't. I love certain types of food, but not all food. I could tell you that I love music, but I don't. I am a fan of certain artists, and the majority of popular music just pisses me off. I could tell you that I watch a lot of TV... actually, that one is true. Just not reality TV. That shit is boring. My current hobbies are trying to create things out of leather - and screwing them up horribly - and trying to build electronics - and failing miserably. As always, I read fantasy and science fiction. A lot. Anything else you don't need to know.
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5 Responses to Well that sucks. (Arduino Stereo Part 2)

  1. trupthi says:

    Retrieving track metadata via AVRCP with RN-52?how is it done?i need help…

    AVRCP supports transmission of the track metadata (artist, album, track title). Is it possible to receive or retrieve this data with the RN-52 module? If so, it’s not clear from the documentation how that’s done. Are the raw non-audio AVRCP frames sent via the UART?

    • SkullnerdSkullnerdSkullnerd says:

      I didn’t pull the metadata through the RN-52. Unfortunately, that chip doesn’t support it, at least not with the firmware that it came from sparkfun with. I picked up a BC-127, and that chip does do metadata. I have only played with it enough to know that I have no idea of what the hell I’m doing, and am trying to learn more before I go any further.

  2. EE-Mike says:

    hello sir, I found this page on a quick google search of the RN52 and Arduino. I suggest looking at the RN52 development board from Microchip.. Go to their site and look at the schematic (RN51-EK). You’ll see that they use an external audio amplifier to drive external speakers/headphones. The amp is like a $3 IC chip available at many places (the part #) is on the schematic. Also use the capacitors (i would just copy their circuit exactly). Not sure if that will solve your problems but it’s worth a shot!

    • EE-Mike says:

      sorry, RN52-EK is the part number, not 51

    • SkullnerdSkullnerdSkullnerd says:

      Sorry it took me so long to approve your comment, gmail decided that my wordpress emails are spam. Bastards.

      Anyway, I have hooked up both the RN52 and the BC127 according to the schematic for the development boards for both. I’ve never been able to get sound over bluetooth for either. I do know that I’m missing a couple inductors for the BC-127 schematic, but I can’t tell if that is absolutely required.

      Thinking about it though, I don’t know if I tried my amplified electret microphone on the RN52… I might have to try that one of these days.

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