Before we mounting everything in an enclosure, just make sure everything is working perfectly. Just turn ON your raspberry Pi3 and wait a 5 second to load everything. Press the button to take a shot using the camera and wait another second. You can hear...
Visit http://hardware-libre.fr/category/hacks-hwl/reseau-domotique/, everything you need is there (but not everything is documented yet, some small bits are still missing)
Make sure you get everything that you need to mod your extruder. Measure everything, check the spacing and clearance of parts, and be ready to get creative.