Quick and dirty Case for the RepRap.me Heatbed Temperature Controller.

http://reprap.me/electronic/heatbed-temperature-controller.html

The three buttons are exposed, the display is under a thinner surface, so with PETG it's still visable. You can cut that part out as well.
There is an opening for the cables.

It's not optimized for a minimum of support generation, so -one way or another- you have to cut away support structure.
It's screwed with 3/4 3mm screws via the bottom part into the the upper part..

I sliced it in KIsslicer, with 3 loops, 25% infill and 0.3mm Layer Height.