I am working on a project with Arduino MKR 1010 WIFI (esp32 onboard) and a microSD sheild (the Mem Sheild).
At a basic level, I am trying to download an audio file daily at a particular time so I can listen on my morning commute. I have no problem downloading the audio file, but all of the ways I have found to play the audio file are not ideal. I am looking for a method to store an audio file I download and play it in a vehicle with two available inputs - 3.5mm aux input or via USB port.
At a more in-depth level, I download a .MP3 file (<100 MB) to a microSD everyday at 5am and then listen to the file at 8am. After the download is complete, the Arduino goes into a standby mode until the next day at 5am. My preferred method to play the .MP3 would be through the USB port on my vehicle. If I transfer the .MP3 to a USB memory drive and plug it into the USB port on my vehicle, I am able to navigate the folders and play the .MP3. I would like to find a solution so I don’t have to transfer the file from the microSD to the USB drive. This is my preferred solution because the vehicle provides the user interface (play, pause, .MP3 file names, etc.) and the USB provides power so only 1 connection is required. Ideally, my final design would look like a USB memory drive and sit plugged into my vehicle’s USB port.
My backup method is to output on a 3.5mm jack and connect to the aux input. The issue here is, from what I have found, additional circuitry is needed to decode a .MP3.
Any advice on what direction to go with my project is appreciated. I have spent countless hours trying to figure out a way to have the Arduino act as a USB mass storage device without finding the knowledge I need. I am considering trying a no so elegant solution which involves physically disconnecting the microSD from the Arduino when it is in standby mode and attaching it to a microSD to USB drive adapter. I am posting because I may not even be aware of other solutions that may be better. I am looking to be pointed in the right direction. Then I can do the research.