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Thread: Don't assume random parts from your parts bin will work

  1. #1
    Senior Member+ MichaelMeissner's Avatar
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    Nov 2012
    Ayer Massachussetts

    Don't assume random parts from your parts bin will work

    I was messing around, and I had some DFPlayer Minis lying around. These are rather simple MP3 players that play MP3 files from a micro SD card. You can control it via a serial line or via simple button press.

    I was thinking it may be simpler to use that for when I wanted sound and to drive two separate SPI displays (i.e. uncanny eyes). At the moment, I'm still trying to convince myself to go in and solder one of the breakout boards to get the 3rd SPI bus/micro SD card, so I was looking for simple backup plans.

    Unfortunately, controlling the 240x240 displays consumes the SPI bus, and you can't put a micro SD card or flash memory on the bus and run the display full tilt.

    I took some time to get it working.

    • So I breadboard-ed and it didn't work.
    • I figured maybe it was the jumper wires, and I replaced them with custom cut wires, and it still didn't work.
    • I then realized I had wired it backwards, and swapped it around, and it still didn't work. At least the DFplayer had a tiny LED that I could tell it was getting power.
    • I use the multi-meter to verify all of the connections are sound, and they are.
    • I swap out the DFPlayer mini with another one that I had bought, and it still didn't work.
    • I verify the MP3 files on the SD card were sound, and they were.
    • Finally, I decide to test the breadboard speaker I had been using, and once I swap it out, then the new speaker started working.

    I must admit, I hadn't even considered the possibility that the speaker was bad. :-)

    The speaker had no name, but it looks like this one:

    This speaker is smaller than the other breadboard speaker I've used:

    I like these small speakers because you can solder them directly to the prototype board. I've found over the years, that for things like costumes, you really don't want that many things connected via external wires that can break or come out at the worst possible moment. In particular, several of the speakers connected with wires, I eventually had to resolder.
    Last edited by MichaelMeissner; 11-10-2019 at 03:06 AM.

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