This is the case for my "AquaBot" IoT project for aquarium automation.
It made compatible with 2 x 2 socket module with size 104 x 104 mm.

Inside the case you can fit WeMOS D1 R2, 4 relay Arduino module, 230 V to 5V power module and small switch. Stepper motor driver and thermometer PCB can be glued to walls inside.

Power cable input below power switch. There are holes for USB cable for programming and external 9-12 V power supply if needed.

Thermometer cable and stepper motor cable should be fixed on top of case below power sockets.

Wanhao Duplicator i3

No

No

0.2

30-50%

Case_Ear.stl should be printed 4 times. They should be glued on top of case.
They have builtin M3 thread. So, you might to clean it before use.
Ears gives 1 mm gap between case and power sockets for ventilation purposes.
Power module should be fixed by 4 M3 screws.

You will need to separate each socket to switch on individually by respective relay module.

In my case project based on Blynk cloud.
It monitors water temperature. Engage food feeder (powered by stepper motor) by schedule.
Sockets used for: two independent lamps, water pump filter, air compressor.
You can make your own purpose.