ZX Spectrum - ZX Microdrive USB Drive Case

Please drop a ❤ if you like this project! 

Why This One? 

Because it's tailored for those ridiculously cheap credit card USBs, which qualifies them for popular giveaway goodies - so very likely you already have one lying around!

They are awful slow, but just perfect for loading small 10-100 kB files into an 8-bit computer emulator or The Spectrum console. Copying your totally legal collection of every piece of software ever written for the ZX Spectrum might take a while, but each individual program will load in the blink of an eye.

Those USBs typically have 8-32GB, but the aformentioned collection is unlikely to exceed 2-3GB, even if you include scans of all the cassette sleeves and have each program saved in several different formats.

USB Stick

You can use most plastic credit card-shaped USB thumb drives, as they are essentially all the same model. Simply flip out the part containing the USB connector and close it back into the casing.

There are plenty of those USB drives available on AliExpress, just be sure to purchase a plastic one, as I think the metal ones wouldn't exactly fit.

If you plan to use it on Retro Games The Spectrum, use only sticks up to 32GB, as partitions larger than that are not supported. When purchasing, keep in mind that 32GB sticks are generally 2-5 times faster than the small 8GB versions, and the price difference is negligible. It is not that you'll run short on the disk space, or you'll notice games being loaded faster, but it will save you time when saving game collections from your computer to the USB.

Printing

For best results I recommend a 0.25mm nozzle with the finest detail settings, or a resin printer.

The top and bottom parts are designed to snap together, but you can use a tiny drop of glue for extra security if desired.

Preparing and Adjusting to Thicker USB

If your USB is slightly too thick preventing the bottom plate from sitting flush against the top part, you can use the ‘bottom.3mf’ PrusaSlicer project file to adjust the negative volume Z-size (Generic-Box). This will deepen the bottom slot until the USB fits properly. Be sure to unlock the XYZ dimensions so that only the Z dimension is altered. 

Please note that increasing Z by 1mm will increase the depth by 0.5mm, as it grows in both directions.

If your USB drive has a printed design on it, you can remove it by sanding with 300–400 grit sandpaper and finishing with 800 grit sandpaper.

The ‘ZX Microdrive’ Text

You have several options to choose from:

a) Print the top.stl with the relief text ‘ZX Microdrive’ and manually paint the text white if you have the necessary skill.

b) Use a multi-material print with the included 3MF PrusaSlicer project file, that will print the body in black and the text in white. It will work even on a Prusa printer without the MMU, just swap the black and white filament each time when prompted (a total of 5 changes).

The Rainbow

For additional detail, you can unpack the PNG files from the ‘decals.zip’ file. Print the 'rainbow.png' (single instance) or 'rainbow-multi.png' (multiple instances) on an inkjet or color printer and attach it for a polished look. 

If necessary, scale the picture until the print fits perfectly.  

Pro-Tip: I printed mine on a regular printing paper, and covered it in two layers of glossy transparent car spray. That's how you get some thin, glossy and smudge-proof decals.

(The picture below is just for illustration - do not print it! Use the ‘rainbow-multi.png’ from the enclosed ‘decals.zip’ file instead.)

3D Render vs The Actual Result

On the left is a 3D render, and on the right is a photo of the actual result. 😁

Putting Your Collection to USB

1. Format the drive to FAT32.
   Right-click on the drive letter, select "Format," then choose "File system: FAT32." If the FAT32 option is unavailable, it means your drive exceeds 32GB. Use a smaller one!
   
    
2. Find a ZX Spectrum games collection.
   These are usually 1-3GB compressed archives (RAR or ZIP files) and are widely available as torrents. Use Google, Bing, or your preferred search engine — you’ll find one!
    
3. Unpack the archive to your local drive.
   The games are usually organized into folders by different criteria, often alphabetically. The files will be in formats like TZX, Z80, SNA, and TAP.
    
4. Organize folders to avoid exceeding 256 files per folder.
   The Spectrum cannot read more than 256 entries in a single folder. To check folder contents on Windows, right-click the folder, select "Properties," and look for the file count under “Contains: X Files, Y Folders.”
   
   For folders with more than 256 files (not counting the files within its subfolders, but each direct subfolder does count as one), break them into subfolders. For example, divide an "A" folder into "A-AL" for games from "Ace" to "Alien" and "AM-AZ" for games from "Amazon" to "Avalon."
    
5. Optional: Further organize your collection.
   You can organize games by company, genre, or any other criteria, as long as no single folder exceeds 256 files.
    
6. Copy your collection to your USB drive.

If you want to use custom ROMs, you likely already know how to set them up. Simply store them in the /THESPECTRUM/roms folder on the USB drive.

Change Log

2024-11-25

• Fitting pins for the top and the bottom part are made 0.5mm longer (now 1.5mm in total).
• Customizable bottom part to adjust to thicker USB sticks.
• Decal PNGs moved to 'decals.zip' to prevent them from automatically being converted to WEBP by the printables.com.