Josh Melnik
Character Animator



Oculus Rift Sensor Cover

I wanted to make a small cap to cover my Oculus Rift Sensors. This is the first project I designed in Blender and took to completion.

You can find it on the thingiverse here (Blender files included)

Print:

Printer: Monoprice Select Mini v2
Supporpts: touching build plate only, plus a skirt
Slicer: Cura
Layer Height: .1313MM (one of the MPselectMini's "Magic Numbers")

Goals:
- Use Blender and figure out a process for future projects
- Fit snug but not so snug it damaged or marked the sensor
- Have a cap with a hinge
- Look cool

Finished Cover

Process
I used Blender to initially sketch out a rough idea, and model some basic primitives into a rough approximation of that sketch:

After I was happy with my rough idea I measured the sensors and set up a blender scene using millimeters as my base unit size.

The sensor diameter was 34mm, so I made my base cylinders with a 34.2mm interior edge, and extruded outwards by 5mm. I felt this would be a sturdy enough print and give me enough clearance.

At this time I also made a small plane with the dimensions of 34.2mm to use as a measuring stick in orthographic views. I beveled in the top of the base so the cap wont hit the lense and put a second cylinder on top for the cap, and that was my starting point.


I then used the 3D cursor as the pivot and rotated the cap up-- I did this until I could locate where the cap would need to hinge in order to rotate past 90degrees and clear the base.

I used this point to place a cylinder and construct the hinge. I made the hinge 5mm in diameter and gave the outer joints .3mm of clearance.

I chose .3mm as my initially I was using a .3mm layer heights-- it felt like a good place to start. I thought the hinge was going to be the hardest part. (this turned out to be nearly perfect for my print, out of sheer dumb luck):


I kept working on the hinge and attached the relevant parts to the cap and base. I added some bevel to the base (for easier print bed removal) and exported a .stl file This was my first print test:



The whole thing was too heavy and too lose. Not only did it slid right off the downward facing sensor, the cap would hang open and dangle. The cap would also come right off when you attempted to rotate it up.

It wasn't a total failure though. The hinge more or less fit... It just needed to cover more of the bar (especially on the innern side). I also realized I had to shed material from both base and cap to reduce weight...

While beveling and shrinking the cap, I added a small groove of .3mm with the hope I could 'snap' it shut-- I was worried it was still too heavy and would dangle. I reduced the outter wall of the base to 3.5mm and cut away as much of the cap as I could while still leaving the top flush so it could print upside down.



This worked remarkably well. The cap fit almost perfectly and the hinge was working as intended. The only problem was it still slid off the sensor... What followed was a day long process of trial and error.

I gradually shrank the interior of the base until it was 34mm exactly. The cover was getting snug and harder to put on but it was still too loose and would slide down ever so slightly. My solution was to add some ridges inside the base:



After more trial and error, ridges of about .2mm (one at the base two near the top) seemed to do the trick. The cover was a little more snug on one sensor than the other but with the internal ridges it almost snaps into place and holds firm.

I am happy with the finished cover. I have printed two sets and so far both fit near perfectly. I learned a lot about 3D printing during this process, and excluded some of my struggles with oozing and retraction as they were noobie mistakes. I plan to print many more things in the future and do a better job of documenting the process along the way.


More to come soon.