But that design used a keyring recoil, which was quite strongly sprung. I wanted one that latched... like one of those USB cables for laptops... so I picked up a couple for cheap and started experimenting.
Step 1: Gather your materials and tools
1) two retractable USB cables. Can be USB extension or power or anything. No electrical signals are transmitted. I got a set of 3 for �1 each in Pound Land.
2) a photo-frame style micro memory stick
3) A spare keyring
5) epoxy resin
6) stiff wire for twisting
7) electrical tape
1) couple pairs of pliers
2) wire cutter
3) measuring calipers
4) Sharp craft knife or set of knives