Home Forums Sparkfun MP3 Shield Library Support Forum Possible Shield Incompatability


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    I am using the Sparkfun Mp3 Player shield and a set of speakers. In addition to this shield, I am using the Shifty VU Shield to read the audio levels so that I can synchronize some LEDs with the audio decibel levels.
    Seperately, the two shields work perfectly. The Mp3 player shield, connected to the Arduino BT ONLY, can play the music through the speakers I’ve connected. The Shifty VU shield, connected to the Arduino ONLY, reads the audio levels sent by my phone via AUX cable while playing pandora.

    The problem is that whenever I stack the two, the music simply stops working. I can’t, for the life of me, figure out why it would do that. Everything is connected EXACTLY as they would be seperately, just stacked on top of eachother. Without even connecting the two through AUX, just stacking them, and the music stops playing.

    Any ideas why?


    Have you compared the pin out of the two shields? IE is there a pin sharing conflict?


    They both use 9, 11, 12, and 13.  But I’m not using any of those pins on the Shifty VU Shield. I’m pretty sure that shield only uses the SPI pins when you connect the “shiftbrites” (the LEDs made for the shield), which I am not currently using.


    The problem that I have with suppliers like the “Shifty VU Shield” is that they don’t share their design files, not even the schematic. So you don’t know what you are buying. Where the best I can find is a flicker picture of the blank PCB.

    That said I see from it and the example code the only thing needed are the analogread()’s of pin A2 and A3 for the left and right channels. If you invoke any of the other PIN commands or WriteLEDArray(); functions in the example such as will interfere with SFEMP3Shield library.

    float adc1avg = 0;
    float adc2avg = 0;
     void loop() {

      adc1avg = adc1avg * 0.95 + analogRead(2) * 0.05;
      adc2avg = adc2avg * 0.95 + analogRead(3) * 0.05;

    I see what you mean, Michael. However, according to the guy who created the shield, there should be no reason why they aren’t working together as according to the code I sent him.

    This implies a hardware issue:
    On the Mp3 player shield, I have pin 7 bent out, and I have a jumper
    going from pin 7 to pin 5 because in the library for the MP3 Player Shield, I
    changed one of the pins from 7 to 5 (because pin 7 is reset on the
    Arduino BT), like you suggested that I do a while back. Without this jumper connection from 7 to 5, the sound
    will not play.

    Do you think its possible that the Shifty VU shield is
    somehow blocking this connection from happening? I am doing the jumper
    from 7 to 5 now on the Shifty VU shield which is stacked on top of the
    Mp3 Player Shield. Does it not work this way? Could this be my problem
    you think?

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