A key ring to safely hold an SD card while being transported.
SD card key ring with 32Gb card inside.
A camera in my car uses a micro SD card. About once a week the card needs to emptied or it runs out of space. I take the card out of the camera, format it on my pc inside them return it to the car. Micro SD cards are small and I have managed to lose a couple by putting one in my pocket for transport but then forgetting about it. Sometime later the card gets lost possibly when taking something else out of my pocket or when I put my pants in the wash, and then I have to go buy a new one.
A key ring made sense as it is something that naturally travels between my home and my car, and as it will be harder to loose. (If I misplace my keys I have bigger problems than replacing an SD card.)
The design has a pocket for the card and a latch that prevents it coming out. The latch is hinged on an 20mm M3 screw which is deliberately tight so friction keeps it in position. The latch is rotated 90 degrees to open and shut. When the latch is oriented so that the attached keys are to the back of the key ring, the flat face of the latch lines up with the pocket and the card can slide in or out. When the latch is oriented so the keys are at the top of the key ring, the flat face instead buts up against the card keeping it safely in the pocket.
The 3d model was made using OpenSCAD and 3d printed. The key ring took ~45 minutes to print with a little clean up and assembly afterwards. I ran a 2.5mm drill through the holes and filed down the excess screw length for neatness.
The latch mechanism works well and should last for a while. It feels solid enough but isn’t too bulky on my keys. All in all, I’m happy with the final result.
3D model in Open SCAD