How to make a VR headset with a pizza box, smartphone and $21 worth of tech

Google is bringing virtual reality to Android phones with cardboard — literally.

The Cardboard project is Google's attempt to bring inexpensive VR to its operating system using items you can find around home or buy at a hardware store or order online. Those include actual pieces of cardboard (an extra large pizza box will do), lenses, magnets, velcro, a rubber band and, if you like, an near-field communications (NFC) tag, which will launch Cardboard automatically. Combine those ingredients with a ruler, glue, scissors and an X-acto knife, and you've got yourself a makeshift virtual reality headset. Detailed instructions are available on the Cardboard corner of Google's developer site.

Grid View

Google handed out its own version of the cardboard box to Google I/O attendees, which came complete with lenses and a QR code for the VR tour mobile app. After we loaded the app onto an Android phone, positioned it within the cardboard box and looked through the lens, we saw fast-moving footage of a stroll through a city.

The cardboard box functioned in a similar way to the Oculus Rift. When we turned our head up, down or side to side, the cardboard box served as a window into the virtual world, and we were able to see what we around us. Unlike the Oculus Rift, the cardboard box's depth of field was low. The app's footage moved too fast, and the head tracking was not as smooth. We started to feel a bit motion sick after a minute.

According to Google, Cardboard is compatible with "most" phones running Android 4.2 Jelly Bean or above. To get started, you can download the free Cardboard app from Google Play, which contains VR tours using Google Earth and strolls through cities like Versailles and Paris. You can even watch YouTube videos. Those interested in developing for Cardboard can view Google's developer documentation for the experimental VR Toolkit.

You can learn more about Google's other recent announcements from its I/O developer conference — including a game called Zombie Gunship Reality, which is based on new technology you can see in action below — in Polygon's StoryStream.

Tracey Lien contributed to this report.