5 Things to check while buying a Cardboard/mobile VR headset

Kumar Ahir
Jan 20 · 5 min read

While Virtual Reality is on surge, mobile VR is still the cheapest option today to experience VR, using smartphone and cardboard based VR headset.

Mobile VR headset

Mobile VR headset is the most basic and inexpensive option of experiencing Virtual Reality.

In a Mobile VR headset, smartphone is used as the main display and head tracking device. The VR box is just a casing that allows to view stereoscopic image on the smartphone display.

However, they come with their own limitations. Some of them come with adjustments that enable a good experience.

Types of Cardboard VR

Absence of these adjustments can make or break the VR experience.

Below is a snap list of things that you should look at before buying a mobile VR headset

1. Lens width for Focal length

The focal length of the lenses in VR box gives a Field of View (FoV) and compatibility with smartphones with larger display/screen sizes.

In market you’ll find headsets with Focal length of 45mm, 48mm, 52mm and 58mm. This Focal length is the distance between lens and the display screen which allows for adjustment of a sharper image.

Cardboard with larger focal length will give bigger Field of View and better experience. So go with larger focal length headsets.

2. IPD adjustment

IPD refers to Inter Pulilatory Distance, that’s the distance between center of two lens. This is to adjust the distance between two eyes of the user. Physiologically each of us has different distance between the two eyes. This adjustment allows you to set the distance between

3. Display and Lens distance adjustment

The adjusting distance between lens and the smartphone display screen will allow the lens to see more of less of the phone display. Depending on the size of the phone display the distance between lens and the display screen need to be adjusted to focus for a sharper image. This is like zoom in/out to get focus. As we have smartphones with variety of display sizes this adjustment is a must else we end up loosing a lot that’s displayed on the screen

4. Heat dissipation

When the smartphone CPU is doing lot of work rendering the 360 view as you move your head quickly, it’s bound to heat up. The VR box need to have proper heat dissipation mechanism so that the excess heat is let off the box and do not harm your eyes.

5. Interaction controller

In mobile VR interaction with Virtual objects happens in 3 different ways

  1. Gaze Fuse interaction — we focus our gaze on an object for certain time say 3 sec and then the action happens. You can opt out of the action if you move your gaze away before time out. This is more like hover over interaction
  1. Gaze Click interaction — we focus on an object then use external controller or the magnetic switch to trigger selection. The magnetic switch momentarily changes gyro sensor values when it passes by. The app is programmed to capture the gyro change event and take action.
  1. External bluetooth controller — this can be a game controller which is hooked to the mobile using bluetooth. You can connect an XBox game controller or a cheaper one. Control buttons are normally mapped to screen tap, volume up/down and sometime tap, drag and release too.

And important thing to note is that the orientation of the controller is not tracked. Hence do not think that you’ll be able to point to all virtual elements in the scene by moving the controller around.

The controller just mimics screen tap event. And the joystick on the controller moves the position of pointer where the screen tap will be done. The joystick doesn’t even controll the camera movement in VR scene.

In a nutshell the controller just acts as a wireless mouse click.

6. Face Cushioning

This is not so important as you won’t be using mobile VR for more than couple of minutes (max 2min) but will give good comfort to the face. It will also make sure that red marks aren’t left. Cushioning also helps in soaking the sweat and making the experience bearable over period of time.

Mind using face mask like the one shown for hygene.

7. Portability and casing

And this is the last optional check you may want to do if you carry your VR box around for work or demo to customers. VR box becomes a bulky setup with all the adjustments and take good space in the bag. So you might consider getting a separate case to keep it safe and sound while making sure it do not add to the extra baggage.

And there are many VR accessory that have bare minimum specs for a VR. That’s pair of lenses. With only lens set the VR headset becomes portable enough to be carrid in pocket.

Personal Recommendations

Based on my personal experience and the VR headsets available in India I can suggest following to be best in flock. A search on amazon (India) for Virtual Reality glasses will give results with many different types of headsets.

The most common of these is shown below.

However, the ones available in market (India) have cheap material quality for the case and the lens leading to bad experience. Torn and loose band, scratched lens, rusted spring to hold the phone all lead to overall bad experience.

Below are the ones I found to be real good quality. This one’s at the time of publishing article and may get new ones added in future.

So happy VRing.

Kumar Ahir

Written by

successful exit in first startup oobi.in, AR VR enthusiast, ex CISCO, SYMANTEC, interaction designer, entrepreneur. More at www.kumarahir.com

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