Google Cardboard

Google, the name synonymous with cutting-edge technology, introduces a new exciting platform, Google Cardboard. No, the Internet gurus at the Googolplex have not decided to diversify into origami, in fact they have developed a device that can be made out of cardboard (and a couple of magnets) that makes virtual reality affordable and accessible for anyone with a smartphone. In this article, we take a look at what all the fuss is about.

What is Google Cardboard?

Virtual reality has come on leaps and bounds in recent years, and with Google Cardboard the virtual reality experience has become affordable for the masses. Google Cardboard is the name of the ‘do it yourself’ headset, but the goal is far greater than that. By making a VR headset accessible for anyone with a smartphone, they are creating a greater incentive for developers to get creative and produce VR applications for the Android platform.Google Cardboard viewer with phone inside playing an application

How does it work?

OK, it does sound a bit far-fetched that a piece of cardboard, two carefully placed lenses and a couple of magnets can turn your smartphone into a VR headset but when you break it down, it seems all too simple. Essentially, the assembly works by presenting two slightly different images, one to each eye. This is achieved by the application on your phone splitting the screen in two and a strategically placed piece of card inside the viewer dissecting the two images. Because each of your eyes is looking at a slightly different image, with the rest of your vision blocked out it creates an immersive 3D environment.

That’s the simple bit covered, however, to really make it feel like you are in a virtual world, the applications rely on the technology inside your phone. The main components being the accelerometer and the magnetometer. The accelerometer detects movement, so when you turn your head with the viewer attached, the screen of the device follows the movement of your head giving the feeling that you are part of the action. The magnetometer cleverly detects the changes in a magnetic field, which we will look into further now.


What are the magnets for in Google Cardboard?

As you can’t reach the screen of your phone when it is inside the viewer, you need some way of selecting and using certain functions to operate the applications. This is where the magnets come in. Inside your smartphone, there is a clever device catchily known as a magnetometer, which detects changes in magnetic fields. It is this device, working with the two magnets that allows you to perform certain functions when your phone is secured inside the viewer.

On the inside of the box, there is one disc magnet held in place with adhesive and on the outside, there is a second magnet that sits inside a groove in the cardboard, held in place by the magnetic attraction to the magnet on the inside. Cleverly, the outside magnet is countersunk on one side so that you can easily slide it down with your finger, then when released, it springs back up to its original position. This movement changes the magnetic field created by the two magnets, which the phone understands like the flick of a switch, however, the function of the magnet switch differs from application to application.

If you buy a pre-assembled or flat-pack Google Cardboard viewer, the magnets included will be approximately 20mm in diameter x 4mm thick and you will have one plain ferrite, ceramic style disc magnet for the inside and either a countersunk or ring-shaped strong neodymium magnet for the outside.

Google Cardboard showing ferrite magnet and countersunk magnet

This arrangement goes against our usual magnet advice as over time, strong neodymium magnets can demagnetise weaker ferrite magnets. Therefore we suggest using a 20mm diameter x 4mm thick countersunk neodymium magnet on the outside and a 20mm diameter x 0.5mm thick neodymium magnet on the inside. However, as all phones have different magnetometers in different positions we found that the magnet switch can at times, be temperamental. Although a little experimenting will get the function working – you may need to change the location of the magnets or try different sizes to get it working perfectly.


How to make your own Google Cardboard

The thing we love about Google Cardboard, is its simplicity and DIY feel. It is possible for anyone to make one for just a few pounds and experiment with the growing number of VR apps. Google provide the plans to be able to create your own viewer, then you just need the magnets and the lenses.

Acrylic lenses – these should be 25mm diameter with a focal length of 45mm. Google suggests biconvex lenses work best as these prevent the image from becoming distorted around the edges. A quick search for Google Cardboard lenses will give you lots of options of where to buy these.

Magnets – Google suggest using magnets identical to these:

20mm diameter  ferrite magnets and 20mm diameter countersunk neodymium magnets

However, we suggest using a neodymium disc instead of a ferrite disc, such as this:

20mm diameter x 0.5mm thick neodymium disc magnetsIt is important to remember that every model of phone is different so it may take some experimenting to find the best position for the magnets.

To take our Google Cardboard to the next level, we replaced the hook and loop tape with self-adhesive magnets.. We think this is a much better closing method that prevents you bending the top flap of the device and eradicates the horrible scratchy sound; yes we are perfectionists!


The best Android apps for Google Cardboard

There are lots of apps that have been released for the Android platform in addition to the official demos released by Google. Such as:

Official demo – the official release by Google lets you experience Google Earth and Street View in 3D as well as watch YouTube videos and other nifty demos.

Chrome Experiments – playable via the web browser on your phone, you can ride a virtual rollercoaster, take a ride of the Great Barrier Reef or visit bears in Russia

The best rated on Google Play include:

Orbulus – This app allows you to select photo spheres uploaded by the photography community just by the movement of your head and you are instantly taken to the place where the photo was taken and able to look through 360 degrees.

DebrisDefrag – hurtle through an interstellar comet belt and blast space rocks without the use of a controller.

VR YouTube 3D videos – Scroll through 3D YouTube videos and use the Cardboard’s magnets to play, stop and select videos. Complete with voice activation.


Does Google Cardboard work with an iPhone?

Google Cardboard is designed to work with applications on its Android platform, not Apple’s App Store. However, if you’re in team iPhone all is not lost as we have scoured the Internet and identified some iPhone applications that do work, however some do require a controller.

  • Shadowgun VR – A demo level from the game Shadowgun. Incredibly detailed, but you do need a controller to use it.
  • Dive City Coaster – Jump in and take a ride on a 3D rollercoaster.
  • The Height – Not for those afraid of heights. Walk around a £D scaffolding but don’t look down!
  • Dive Zombie – Fight off the zombie hoards in this first-person shoot-em-up
  • Moorente – Instead of zombies, Moorente lets you shoot ducks out of the sky by moving a crosshair with your head movement.
  • YouTube – Yes YouTube! YouTube app and just search for “3D trailers for 3D glasses,” then play any video that’s split into left and right halves.


Don’t panic, the magnets will not cause your smartphone to self-destruct. If you are nervous about having strong magnets near your phone, read our article about the effects of a magnet on a smartphone here.

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