Grumpy_Mike:
No that would not work either.
What would happen is that the signals into the SD card would back power the audio player’s circuits and power it up, giving you exactly the same problem.
I figured something along these lines.
So even if I cut ground from the DFPlayer, the circuitry on the player could snake around somehow and get back to ground maybe on the ground pin of the SD card because I can't cut that if I want to use the Arduino SD library? Or possibly double up a voltage somewhere? Does this sound like I understand-ish?
TomGeorge:
I think you need to read the DFRobot documentation, the Player is just that, A PLAYER.
It has no hardware or firmware to record files to the SD Card.
The documentation informs you that you need a PC to load files onto the card.
Oh come on, it's not that I didn't read the documentation before I bought 200 of them, it's that my brain didn't tell me I couldn't access the SD card for writing. ; )
TomGeorge:
The Player pins do not even allow you access to the SD Card directly, and where would you get the software to write to it if you could.
Yes, I had come to the realization that the DFPlayer's pins don't give me access to the SD card . I was hoping Grumps was going to okay me bypassing the player pins and hooking straight up to the pins on the SD card. Turns out my incredible idea needs a tri-state buffer. Which I think would also need to be connected not where I can easily connect it? I'd need to buffer both when the player accesses the SD card and when the Arduino does as well? Which I'm thinking maybe I need to design my own sound decoder buffer type thing?
TomGeorge:
It is not designed for that job, especially at the low prices you can get them these days.
wvmarle:
Just get a separate SD card board. Even cheaper than the DF player and you can use it to read and write files.
Get the proper tool (part) for the job, leave the DF players for playing audio files.
I've bolded the following because this is the crux of my ten page essay I have concocted.
Right so I'm on board with getting the right parts for the job, but what does the job of playing music/sound from a micro SD card that I have interfaced to my ESP32 so that I can manage the files from a remote server?
Can I stream the songs through DFRobot's USB pins? I can't seem to find documentation for the USB pins on the DFPlayer.
BabyGeezer:
IMO that's irrelevant to my analogy.
i believe you can write a program to select the tracks to be played.
It wasn't supposed to be relevant to your analogy, it was supposed to be a different analogy that is relevant to the IC components. ; )
Yes, my microcontroller (DJ ESP) can definitely select mp3's from the prepared library like a DJ can put on whichever record he has at the station's library onto the turntable (DFPlayer's MP3 Decoder).
I love how the DJ is able to change the songs on the turntable, that's great. I just don't like the way the player is asking me to change stations, by removing the SD card and putting a different one in there. I would prefer that the player allow me to electronically hand it a new library.
I do also understand no matter how much I'd prefer to make a telephone call on an FM receiver, it won't change the fact that I'd need a whole bunch of new parts and there probably is no easy interface to hook it into the receiver.
BabyGeezer:
i don't know enough about serial communication to assume that as a given.
perhaps there is additional cost in making the hardware capable of two-way rather than just reading?
Yes, I think it is definitely that there would be more hardware needed at a minimum to share the SD card as Grumpy_Mike was saying. I'm sure other stuff as well.
Thank you everybody for your help and discussion.
