We’re definitely pretty fond of the DIY MP3 players here at Hackaday, but we don’t think we’ve seen one like CartridgeMP3 from [jpet26] before.
All the electrical components are what we’ve come to expect. [jpet26] uses the popular VS1053 decoder to read MP3 files stored on an SD card. He also includes a potentiometer for adjusting volume, a USB C port for power and programming, a headphone jack for the audio output, a general-purpose status LED, and an on/off switch.
But what really caught our attention is the form factor [jpet26] selected for his MP3 player. Though the MP3 files are stored on an SD card, he uses a cartridge interface, similar to that of a Nintendo 64 or Game Boy of yesteryear, to choose which MP3 to play from the SD card. The cartridge interface is tied to a few GPIO pins and by reading the status of each pin, the device determines which MP3 to select.
You could say that the cartridge is a little unnecessary, and we wouldn’t argue with you. The cartridge doesn’t actually store the MP3 files, the SD card does. It might make a bit more sense if the cartridge housed the SD card itself with a few select MP3s stored on the card. That would be a quirky way of sharing your favorite playlists with your friends. So, yeah some clumsy handshaking there, but who isn’t guilty of that from time to time? We like it and thought you might appreciate it as well.
Cool MP3 player, [jpet26]! May we suggest a speaker for V2? And maybe some flex cables.
Not at all. Having just few pre-selected songs available is more in line with a cartridge system; you wouldn’t or couldn’t download just any game onto a cartridge either. You had Tetris, Super Mario 3, and then you had to go begging mom for more allowance because game cartridges were expensive.
Does he have to blow 8nto the cartridge slot to make it work?
B^)
It’s like that one 1970’s Pong console that used “cartridges” which simply jumpered contacts to select from the games that were built into the console. Cheaper than a multi-contact rotary or slide switch and made the buyer think they were getting something more than they were, and/or squeezing more money out of the buyers to access stuff they already had if the console didn’t come with all the “cartridges”.