Amplifying a 3W speaker from an Arduino & MP3 player module

Discussion in 'The Projects Forum' started by awwwt, Sep 9, 2015.

  1. awwwt

    Thread Starter New Member

    Aug 24, 2015
    Hello everyone,

    I am currently working on an installation that uses an Arduino Nano to trigger a sound from an SD card in the DFPlayer Mini mp3 player module. The tracks play on a speaker like this, and here are the specifications-

    Speaker - 45mm
    Output - 3w
    Frequency response - 280Hz - 16kHz
    Operating voltage - 5v

    My issue is a bit of a strange one, but basically the speaker has loads of un-useful settings (eg. bluetooth mode) that I need to bypass because I simply need to use the speaker as an output and can’t have the introduction tones and annoying voices announcing the mode I’m in every time I need to turn the project on.

    To do this, I am currently connecting the - and + wires from the speaker to the mp3 player module's SPK_1 and SPK_2 pins, however the sound is not nearly as loud as it could be (as it is when you just plug your iPhone into the whole thing), as there is a built in amplifier to the circuit board that I’m not using by bypassing the rest of the speaker….

    So - I think the best option is to build an amplifier and forget about the speaker’s circuit board. (I tried to take the surface-mounted IC from the board earlier which is this one and it did not work...)

    A slight side note - the mp3 module does have a presumed 'amplifier' that I'm not sure I'm using. On the data sheet for the module there seems to be ports to drive ‘the earphone and amplifier’ (DAC_L/R), however I have been using the SPK_1(+) and SPK_2(-) pins. I will try and connect these when I next have a chance, but if anyone knows more about how I might operate this module better, please say - I am currently only using the left hand side of the mp3 player’s pins to achieve my project.

    Most important question is, I was wondering if anyone could suggest me a good amplifier IC to use given the specifications of my circuit, and the best way of assembling the amp/ any advice. I am new to amplifiers but I think I need a stereo amp not a mono one? And I am unsure whether the mp3 module’s ‘amplifier’ will affect my choice. Bottom line, I need more sound!!

    I posted a few weeks ago about the same project here if you seek more detail but hope it all makes sense.

    Thanks so much!