I want to be able to wirelessly change the music on the "USB drive" in my car; i.e. the "drive" is actually an always-on computer, e.g. a Pi.
Change the music from the computer at home and be on my way?
Nota bene, do not mount it two places at the same time!
Something I’d still like to add is a USB OTG emulation of iOS/Android/iPod/etc, so that the currently playing track shows on the dash, steering wheel controls can be used, etc, but my last experimentation a couple years ago didn’t go anywhere. (All the open source stuff for emulating CarPlay and Android Auto seem to be for the other direction: the dash, not the device.)
As in, I'm fine with the SYSTEM that plays music now (I have Toyota Entune) and I don't much want to mess with it.
I literally just want to be able to remotely change the files on the USB drive in the car -- without ever having to take it out of the car; that's it.
Best example of such a use-case was someone who wanted to make an old printing press fetch files its files from the internet. The press only had an interface for floppy disks. He replaced the floppy disk controller with a floppy emulator that exposed an USB port. Connected a phone with DriveDroid. Synced usb image files from the internet to be exposed over usb mass storage. The image files were fat images that hold the printing job files. They were generated by the server automatically. It worked pretty well from what I heard.
Similar solutions are also popular in the 3D printing space, look up Fysetc or BTT wifi sd cards.
It's a USB gadget kernel module that pretends to be an iPod to stream music to car/etc.
Pity the market keeps evaporating. Very cool product.
I recently realized I can use a $15 USB capture card with an HDMI input on the other end to snag the video feed of a Pi or anything else that can output HDMI. As I use Linux, you can tap into the /dev/video<number> device as if it was a camera, using VLC/OBS. (There's also a paid app on Play store that allows me to also do this on my phone as the display side, using OTG. Would love to be able to use my tablet running a de-Googled LineageOS as well, but that'd entail figuring out how to crack/patch out Google's license checking library, and I haven't found any FOSS alternatives, ugh.)
From there, making the (my) dream happen would be if there was some convenient way to use the same device that's tapping into the video out as the keyboard/mouse input, much in the modal way of VMWare/VirtualBox, where it overtakes your input, and using the hotkeys to release when you want to switch back to your tasks on the host.
In particular, I have a Flipper Zero that doesn't get real use beyond novelty functions and have been wondering if that (or something like a ESP32/ESP8266 computer) could help facilitate that. My skillset is nowhere near that close to the metal.
At least, re: your post I'm piggybacking, and coming from knowing the capabilities of the Flipper Zero, I wonder if RubberDucky/BadUSB payloads could bring you any closer to meeting the spirit of your goal. Or, some sort of rsync like mechanism baked into the Pi when it (automatically) connects to a detected, saved network. Or, a RubberDucky/BadUSB payload on-demand to fire off an rsync.
For the esp32 there is this official example of what I think is faking a usb drive: https://github.com/espressif/arduino-esp32/blob/master/libra...
Not all ESP32s support USB OTG and I don’t have the correct one here atm to test with. Not sure how much more work would be needed to serve files from sd card.
You could then use a web server on the esp32 to transfer your files