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Google releases Cardboard VR viewer specs and SDKs

Dec 11, 2014 — by Eric Brown 6,549 views

Google released open hardware specs and Android and Unity SDKs for its “Google Cardboard,” which turns smartphones into a low-cost stereoscopic VR viewers.

Google Cardboard was born as an informal virtual reality brainstorming project inside Google earlier this year, and a DIY kit was given away free to Google I/O attendees in June as a proof-of-concept device. Cardboard was a hit, and Google quickly released the design files along with free Android and iOS viewing apps. Four companies now sell self-branded versions of the cardboard-constructed kits ranging from $15 to $22 for basic models. A half million kits have already shipped, says Google.

Now, Google has released Google Cardboard’s first fully formed Android SDK, as well as the first SDK for the Unity gaming engine. The open source kits let you modify applications, videos, and images to appear in 3D on the device, or build new ones.

Google Cardboard kits (left) and fully assembled
(click images to enlarge)

The Android SDK enables applications with features including lens distortion correction, head tracking, 3D calibration, and side-by-side rendering. Other features include stereo geometry configuration and user input event handling.

Cardboard with smartphone
(click image to enlarge)

Google also released a new set of hardware specs under open source license, with improved design templates and manufacturing guidelines. In addition, the company has launched a collection page on Google Play containing over a dozen Cardboard-ready apps. Most of them, including Jaunt’s Paul McCartney and Jack White immersive music apps, are free. Some these apps are also available on iOS.

Cardboard-ready Android apps including Paul McCartney (left), Volvo Reality test drive (right), and Proton Pulse 3D (bottom)
(click image to enlarge)

Google Cardboard is simpler than Android-based 3D viewing devices such as the Oculus Rift-infused Samsung Gear VR, which went on sale for $200 this week. It’s also somewhat less advanced than Carl Weiss’s $99 VR One, which is due to ship soon.

Samsung Gear VR (left) and Carl Weiss VR One

Google Cardboard offers the same basic design concept, which puts your own smartphone to work as the computer and display. However, it has an advantage over both the Gear VR and VR One in that it supports a wide variety of Android phones, as well as the iPhone. The Gear VR requires a Galaxy Note 4 phablet, and the VR One requires either a Samsung Galaxy S5 or an iPhone 6. Although Cardboard devices are optimized for major Android phones, like Google Nexus 4 and 5, Motorola Moto X, Samsung Galaxy S4 and S5, and Galaxy Nexus, other phones should also work.


The device displays 3D scenes with binocular rendering. It can track and react to head movements, and it communicates with apps via a magnet input that interacts with the phone’s magnetometer. An optional NFC tag informs the phone of your exact configuration.

Two Cardboard versions: Dodocase VR (left), and I am Cardboard’s foam-fabricated Eva
(click images to enlarge)

Cardboard models are available from DODOcase, I Am Cardboard, Knoxlabs, and Unofficial Cardboard. Specs vary a bit, but the $15 UC VR Headset version of the Cardboard from Unofficial Cardboard is typical. (Note: this is the first LinuxGizmos specs list to include a rubber band.)

Specs listed for the UC VR Headset are as follows:

  • E-Flute corrugated cardboard
  • 2x Asymmetric-BiConvex optical lenses (25mm diameter, 45mm focal length)
  • Forehead strip
  • Ceramic disc magnet (3/4 in.)
  • Neodymium (rare earth) ring magnet (3/4 x 1/8 in.)
  • 2x pairs of velcro strips
  • #32 rubber band
  • Programmed NFC tag (NTAG203 sticker)
  • Optional head strap (add $4.95)

Google Cardboard components unpacked
(click image to enlarge)

In early 2015, Google will provide a viewing calibration tool. This will let manufacturers and makers tailor the viewing experience to a particular Cardboard spin-off’s unique optical layout.

Knoxlabs’s $45 Knox Aluminum

A recent Engadget hands-on review by Nicole Lee praised the Google CardBoard viewing experience as being “surprisingly bright and sharp.” The device’s head tracking and positioning, which uses a phone’s accelerometers and gyroscopes, is “pretty responsive,” writes Lee.

Particularly impressive is the magnet-enabled switch that lets you trigger actions and select menu items, writes Lee. “It truly felt like I was using an old-school View-Master from my childhood, except now I can do things like watch movies and play games,” adds Lee.

Further information

The Google Cardboard SDK announcement may be found here, and the SDK site with free downloads can be found here.

Google Cardboard kit variations can be bought ranging from $15 to $45 from sources including DODOcase, I Am Cardboard, , and Unofficial Cardboard.

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One response to “Google releases Cardboard VR viewer specs and SDKs”

  1. Nilesh Yadav says:

    Also $25 Converge VR made from Plastic, side and head strap and Leather flap holder.

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