Before christmas I bought myself a smartphone VR viewer (a la Google Cardboard, just fabricated out of plastic instead of cardboard). I spent ages pondering whether I should buy one or not, since I didn’t actually NEED one, and it would just open up a world of new projects that I don’t have time for. In the end I did it, because the $30 or so that it cost would be offset by not being drawn to eBay and Aliexpress all weekend trying to find the best deal and then talking myself out of it. I bought the VR Box 2.0:
The reasons I picked this unit were fairly simple:
- No particularly bad reviews
- Adjustable lens position for both pupillary distance (distance between the centre of your eyes) and focus (distance from lens to eye)
- Low cost
- Moderate specs, enough for my purposes
- Sliding panel for exposing camera
- Openings for power and headphones
Overall it functions, and you can get a reasonably good VR experience. Some people will complain about the cheaper VR sets not having an immersive enough experience, but I don’t think that a few degrees extra Field Of Vision will really fix that.
Yes, the headset can get a little heavy on the nose, but that’s nothing that can’t be fixed by adjusting the straps or adding a little extra padding.
This headset doesn’t have the built in magnet switch for interactive with applications, so I made up a little dongle with a small rare earth magnet inside. When I bought the headset, it also came with a miniature bluetooth gamepad, and while many apps don’t accept gamepad inputs (for some bizarre and stupid reason), quite a few do.
In fact, the main issue I had with this purchase was dealing with the seller on Aliexpress. See, when the VR Box 2.0 arrived in the mail, I had a look at the sparse documentation, and it didn’t have a QR code for calibrating the Google Cardboard apps to the headset. There was a shrunk down image of a QR code in the pamphlet (which in itself looked like it had been photocopied onto glossy paper, so the image was blurry), but it wasn’t readable by the phone. Naturally I contacted the seller, asking if they could send me a copy of the QR code required. After a several responses along the lines of “the QR code is in the documentation” (which is wasn’t), and “please see the manufacturer’s website” (which could not be found, nor would the seller give me the URL), I told them that I’d have to leave a negative feedback if they didn’t help. They didn’t, so I did.
In the end, I used the Google Cardboard QR Generator: https://www.google.com/get/cardboard/viewerprofilegenerator/
I use a Samsung Galaxy Note 4 (which has a 145mm screen), and set up the QR code to suit my lens position, so your inputs relating to screen and lens position might be a little different, but the rest should be okay. Here are the values I used:
Primary button type: Magnet
Screen to lens distance: 44 mm
inter-lens distance: 61 mm
Screen vertical alignment: Centre
Distortion coefficients – k1: 0.1
Distortion coefficients – k2: 0.02
Field of View angles: all 50°
Note: if setting up your own QR code for this or another viewer, the fiddliest bit is getting the distortion coefficients set up correctly. These coefficients determine the adjustments for distortion, and need to be set up to ensure that vertical and horizontal lines stay straight, and don’t curve in or out at the edge of the screen. There isn’t a written description of these coefficient, but if you increase/decrease the values significantly you’ll see what they do in the little diagram on the right. k1 I believe sets the distortion for the 2nd power, and k2 sets the distortion coefficient for the 3rd power. For you, this means that if you look at the vertical lines in the VR grid preview (while setting up the QR code parameters), and they are curving in or out, adjust the k1 input until they look pretty straight, particularly in the centre 2/3 of the screen. Then, if the lines are still distorted near the edge of the viewing field, adjust the k2 coefficient in the same direction. If the ends of the lines have distorted too far, just take k2 back the opposite direction instead.
Here’s the QR code that I came up with, and it looks significantly better than the one I used just to test out the headset:
Overall, I’m happy with it! but… Now I have to figure out how to write a VR app… Yet another project. Sigh.
If you found this blog post useful at all, I encourage you to check out my first android app: The Lightbulb Audit . As I said, it’s my first app, so please leave positive reviews. If you have any criticisms, comments, bugs or suggestions, please leave them as a comment on my corresponding post on this blog: here.