Arduino Nano Enclosure
This is going onto a UAV being flown by the USDA, for detecting pinched irrigation lines in crops. The UAV manufacturer has no means for triggering other than TTL, so I added the Nano.
It screws down with M3 16mm screws (I need to check). There is a built-in reset button, that can be easily removed if you don't want that feature. There is also a window for viewing the LEDs. I would recommend a dollop of clear silicone sealant here to keep water out.