USBvalve Case

Recently I discovered and built the [USBvalve project on Github](https://github.com/cecio/USBvalve). It's a great project, but I wasn't quite satisfied with case model provided, so I created my own version.

Also, I somehow didn't think to check if maybe someone else had already encountered the same issue. So this isn't the first alternative case for the USBvalve.

Currently, version 1.2 of the USBvalve project PCB and a 128x32 pixel OLED display are supported.

Be sure to align the Pi pico exactly before soldering and use the ["Pi Pico Spacer"](https://www.thingiverse.com/thing:4748043) to place the OLED display module correctly.