Portable USB LED lamp

This is a portable version adapted from igorF2's great design of 3D printed articulating LED lamp. https://www.thingiverse.com/thing:2505394

In order to reduce post-printing works, I used commercial UBS-A LED lights and USB-A male to female cables, and USB plug charger (or portable charger).
USB-A LED lights is like this: http://24h.pchome.com.tw/prod/DCADI8-A90069XW8
USB-A male to female cables I used: http://24h.pchome.com.tw/prod/DYAP8N-A9007M12E

For standard assembly, you need:
ring