The housing was designed in Fusion360. First, the parts for all the hardware were designed and printed individually to ensure a good fit. After that, it was back to Fusion360 to join the parts together with channels for the wiring, which is the .STL file that you have here for download.
Be sure to print with the lens part on the print bed. Surface supports will be needed for the Trinket portion of the housing. Printing at .2 resolution and 15% infill should yield good results.
Clear PLA should be used for the lens portion of the housing for proper light diffusion. If you want the rest of the housing to print in a different color though, you can edit your gcode so that the print pauses at a specific layer height, which will then allow you to swap filaments. As long as your printer is running Marlin firmware (aka accepts gcode) then you can use the Prusa ColorPrint utility (https://www.prusaprinters.org/color-print/). To change colors at the Trinket portion, enter in a color change at layer height 7.80.