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Help building small bluetooth speaker

Discussion in 'Radio and Wireless' started by QuilavaFlame, Feb 7, 2013.

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  1. QuilavaFlame

    QuilavaFlame

    6
    0
    Feb 7, 2013
    Hiya,

    I'm new here, so this is my first post. I could really use some help figuring out how to configure a small Bluetooth speaker I'm trying to build. For the project I need to use as little components as possible to keep it small. I have a small Li-ion battery, a bluetooth module, small amp, and a speaker
    Speaker:
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/20130206_220835.jpg
    Amp:
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/20130206_220750.jpg
    BT Module:
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/20130206_220702.jpg
    Battery:
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/20130206_220552.jpg
    BT Module Diagram:
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/T2e4SGXadaXXXXXXXX_124189821.jpg

    So far as I'm thinking, the speaker should go into the "R+" and "R-" of the amp, then from the amp to bt module, "RIN" to "SPKN", "GND" to "SPKLP", and "LIN" to "SPKRP", and then the amp "VBAT" and "GND" to the battery. Is this at all correct? If not would you mind pointing out what should be connected where? And also where I may need resistors and what not, I'm not exactly sure.

    EDIT: I'm not sure what the battery voltage is, I just ripped the battery out of some electronics i had lying around

    I was just going to disconnect the battery and charge it with this quick charger, I'm hoping I don't have to watch my battery go up in flames :]
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/20130207_101524.jpg

    I found a datasheet for the BT module
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/T2DyqGXbxXXXXXXXXX_124189821.jpg

    And while i couldn't specifically find a datasheet for the amp, I found a datasheet for the PAM8403 chip on the amp, if that's of any help. And a picture that was pretty helpful.
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/PAM8403-circuits.jpg
    http://i215.photobucket.com/albums/cc232/QuilavaFlame/2013-02-07-00-45-05-544396602.jpeg

    I'm now positive where the speaker, connects to the amp, and where the battery connects to the bt module, but I'm still fuzzy on how to connect the amp and the bt module, and if ill need any resistors or not?

    Thank You,
    Quil
     
    Last edited: Feb 7, 2013
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,404
    2,777
    Jan 21, 2010
    Assuming the battery voltage is correct, each board will have a Vbat (or similar) and a gnd.

    I note you have no charger. You need something to control the charging of the battery or you will have the joy of watching your battery explode in flames.

    I note that there are a lot of connections to the bluetooth module. It is quite possible it requires external support circuitry and/or logic.

    Better than pictures would be links to the datasheets for these devices.

    edit: I Just noticed the last link had a different icon :) Yeah, it seems that the speaker left and right should go to the left and right inputs. The datasheet will probably tell you that spkn is the ground lead, but if it is isolated from ground you may have issues. (datasheets, datasheets, datasheets...)
     
    Last edited: Feb 7, 2013
  3. QuilavaFlame

    QuilavaFlame

    6
    0
    Feb 7, 2013
    Also when I use my multimeter to check the voltage it waivers between like .05v and .5v, am I doing something wrong, theres always the possibility its broken as well, its a very cheap multimeter.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,404
    2,777
    Jan 21, 2010
    what voltage is that?
     
  5. QuilavaFlame

    QuilavaFlame

    6
    0
    Feb 7, 2013
    I'm not positive but I'm assuming its a 5v battery. Also did you see my "EDIT", I added some datasheets :)
     
  6. Harald Kapp

    Harald Kapp Moderator Moderator

    10,090
    2,157
    Nov 17, 2011
    The question is not about the magnitude of the voltage, but between which points do you measure the voltage?
    Also: a 5V battery is very very untypical. Typical batttery values are 1.2V, 1.5V, 3V, 4.5V, 6V etc. You should know what components you use, that includes the battery.
     
  7. QuilavaFlame

    QuilavaFlame

    6
    0
    Feb 7, 2013
    Oh, I see. Do you think the +5v quick charger I pictured up top might hurt the battery, if i don't know the voltage of the battery? If so, is there a better way to go about finding out the voltage, my multimeter just keep reading .05v or so, does the battery need to have a charge?
     
  8. Harald Kapp

    Harald Kapp Moderator Moderator

    10,090
    2,157
    Nov 17, 2011
    You cannot use a charger in place of a battery.
    The charger is designed to charge the battery according to the battery's chemistry. It is not designed to supply power to a circuit. That may well b ethe reason for the fluctuating voltage you saw.

    What a question!. Of course. That's what chargers are for.

    Charge the battery, then re-connect the battery to the circuit.!
     
  9. QuilavaFlame

    QuilavaFlame

    6
    0
    Feb 7, 2013
    Im not trying to use the charger in place of the battery, I was just wondering if the charger might over power the battery and destroy it. And what I meant by "does the battery need a charge" is does it need a charge to be read by the multimeter? But nevermind that, im sure I can figure it out. What I really need help with is how do I connect the amp and the Bluetooth module?
     
  10. Harald Kapp

    Harald Kapp Moderator Moderator

    10,090
    2,157
    Nov 17, 2011
    If you don't know the voltage of your battery, you can quickly destroy it by overcharging. This might be a lithium battery which can strat tu burn if not treated properly. So go get the parameters of your battery.

    For getting your setup running, put aside the problem of the battery and use a power supply with well defined parameters (lab bench supply or known battery). Once your setup is up and running, you can still add the battery.

    As for the connection from teh BT module to the amp: Steve has given you all information that can be gained from your pictures.
     
  11. QuilavaFlame

    QuilavaFlame

    6
    0
    Feb 7, 2013
    Oh ok, yea thats a good idea for the battery, ill just use some other power source for now.

    I've added some extra pictures including datasheets in my edit, do those help figure out the configuration?
     
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