The fume extractor from Davide83 is a great design! I just didn't want to glue the electronics to the case. Therefore I added very simple holders for the USB module and the step up module. The battery holder is added with double sided tape. Here I also included the stl files of my holders which I added to the case. If you print them you can test if your modules fit before printing the case part.
I also added a hole for the LED of the USB module. This way I can see if the battery is fully loaded.
The missing two parts of the case you find at Davides thing.
0.16 mm layer height / 0.4mm nozzle
Extrudr PLA NX2 1.75