Based on the great design of anjanathisal I created this case with the following changes:

• More venting holes on top bottom and sides to allow more air flow
• Holes for screws to fix the case that its not accidentally opening
• Add screw cylinders to case top to fix the PCB inside
• Make the case 2mm higher to give some space to add ons inside

I have here two variants. One has an additional hole for a antenna connector. I use it for my HM-MOD-RPI-PCB ELV module. Its for my openhab homematic integration.

Update 2019-12-05: The temperature in the passive cooled housing (using my openHAB configuration) was still over 60 degrees Celsius. I decided to add a top cover with fan... Now its arround 42 degrees with the fan connected to 3.3V!