All the virtual reality announcements from Google and Oculus inspired me to build a headset for myself. Using the large iPhone 6 Plus screen and the available apps from the App Store, all that was left were lenses and a frame. The frame was 3D printed from CAD models made using Onshape.com. The lenses were also 3D printed but then subsequently molded and cast in clear resin. Finally, they were sanded from 220 - 7000 grit sandpaper, then further polished with compound and polish. It's a tedious process where each step can't be rushed to achieve an optically clear finish. However, for a first try at 3D printing lenses on a consumer printer, I was surprised that they worked so well!
Never having experienced VR I didn't have high expectations. I showed my contraption to an Oculus dev kit owner, and they were marveled at how simple yet effective it was at inducing the virtual reality experience. After building the first prototype, I subjectively compared it to an Oculus Dev Kit and was very excited for the future. I'm not making any claims that this hack holds a light to an Oculus, but for building it completely from on-hand supplies and tools, I'm more than pleased with the hack-job results.
Assuming that aligning the lenses would be difficult, I opted for a design where the user could adjust each eye independently. I had no idea how to start accounting for variety of faces, eyes prescriptions, and eye-wear so it made sense ( at the time ) to tackle each eye independently and let the user do what's most comfortable for them.
The iPhone acts like the central structure which the user safely holds with both hands. The two eye pieces friction fit inside padded u-channels which can flex independently to conform to the user's face. The user can lightly press the device to their face to block-out light. The results were surprisingly effective once the user got it just right but it was tricky to actively keep aligned and turn their head.
60% of the inspiration for project was answering the question: "can a consumer 3D printer make satisfactory lenses?" Google Cardboard recommends these lenses, 25mm 40mm focal range bi-convex so it was a good enough starting point. Again, using the free OnShape I made a CAD model of the master. I then used silicone mold material and waited for the result to cure, pulled the master, and cast resin copies in its place. Finally, endless sanding and polishing created a clear-enough lens. The hand polished lenses were not impressive. Even compared to the mass produced lenses they were very blurry. However, the self-made lenses worked in allowing the user to focus on the iPhone screen inches away from their eyes! The defects in the lenses made it difficult to focus on any specific thing. However, especially during motion that didn't require focusing like turning the head, the user felt presence and immersion in the virtual world. It was clear that improving the polishing step would return the biggest benefits.
The first prototype was literally crushed in my car door. After moping for a couple days I took advantage of everything I learned and build a MUCH simpler frame in 30 minutes. This frame simply sits on any smartphone screen. It's light and also held in place while also holding the phone. The lenses can slide closer and further apart but otherwise the focal distance is fixed so the adjustments stop there. No fiddling and much less to take you out of immersion.
Instead of hand polishing each lens, I tried 3D printing a chuck and spinning it in my drill press. Unfortunately this method creates a unacceptable swirl in the middle of the lens. The right lens (shown below) is polished with by carefully polishing by hand. Gleaning from the "How It's Made" Lens episode, I suspect lens manufacturers spin the lens and the abrasive to avoid the center swirl.
Q: "Why are you making your own VR lenses when you could buy better lenses for a couple bucks on Amazon?"
A: I want to 3D print my own prescription glasses and now I'm very close to achieving that dream.