I am making a project that plays several sounds using a DFPlayer Mini mp3 player and a micro sd card. The size of the sounds I normally play is less than 20 MB, so a lot of space in the sd card is unused. I was wondering if there is an alternative to use an SD card to store the mp3 files, and if there is, what would be the best approach to switch to use this alternative.


  • what please is the problem you try to solve? you want a only 200 MB storage and not more? – Juraj Apr 22 at 16:36
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    why is the SD card free space an important factor? – jsotola Apr 22 at 17:23
  • The SD free space is not really important, but I wanted to know if there was a "better" alternative or a cheaper one. – PayToPwn Apr 22 at 18:23

The problem of all alternatives I can think of is a commercial one:
Its more expensive than to waste space. So if you look up your facvorite online dealer you will quickly find out that e.g. buying the cheapest 1GB SD card costs double than buying the cheapest 32GB card (6$). So the more space you waste the cheaper.
Get an used 512MB or 1GB card (cost in my country around 1$) and be happy with the space reserve.
Of course if saving space is a topic and not money get 20 x 1MB eeprom I2C boards (20*3$ from china), solder the hardware (you'll need some more parts to manage the board addresses), get a power source, write a library for managing the memory and after spending around 100$ and a lot of time you saved up to around 15.98 GB of free space but not the environment.

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  • I see, so it's always cheaper to use SDs to save mp3s than to store in EEPROMs, right? As you mention commercial uses, how do they solve this issue in commercial products? Do they also use SD cards? – PayToPwn Apr 22 at 18:34
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    Depends - falsh rom in industrial use is cheap (see usb sticks) but there are no payable solutions for mkers. But if you have an old usb stick start making your own project. As an SD card is basiclly a flash rom (the biggest parts are the contacts) you could also desolder the sd-slot and directly solder the card onto the DF-Mini, but whats the difference? SD cards have no moving parts so its normally shock proof (and can be secured with tape) if thats an issue. So you see there is a difference between maker and industry ;-) – Codebreaker007 Apr 22 at 20:41
  • Thanks for the great explanation and examples @Codebreaker007 ! – PayToPwn Apr 23 at 6:47

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