Augmented Reality Headset (AR, not VR)

Augmented Reality, when objects from the virtual world come into our real world. This field is picking up interest (Pokemon Go), however, the blocker to experimenting with mixed reality is lack of an affordable device to a hobbyist like me (Hololens costs $3000).

Ideation

I was day dreaming about 3D projections this afternoon when this idea popped up.

We see objects in our world by the light reflected from them. Our mind creates a projection of object in the line of incoming light. To mix a virtual object into my real world, I need to find a way to project it such that it creates a kind of illusion that the object reflecting light is in front of me. That way my mind will believe that the virtual and real objects are both in the same plane.

Long, long, back, in school days, I built an optical illusion Tableau that would transform from Goddess Parvati to God Shiva and back to a viewer. I have to document that project and share, but for now, I used that same technique today.

How it Works

A glass is placed at 45 degree angle, such that we can see through it to the object in front of us. Another source of light is kept perpendicular above the mirror. The light from this source will partially reflect from the glass surface and beam straight to the observer, who will get a sense that the light is coming from straight ahead. Thus both objects will appear to be in the same line.

Since light is partially reflected from a surface, we need a strong source to project it clearly over to real view.

Production

I used a shoe box. I needed a smaller one, so I used the box from kid shoes.

Step 1

I made a few cuts to make place for my eyes, and another one on opposite side to look through. I also made a special cut to fit my phone on top. This cut was made a few mm larger than my phone dimensions, and diagonal cuts in the corner so they create a dent for phone to fit in.

Step 2

I painted it black from inside so there is no internal reflection. Otherwise it will interfere with the image we project and create a blurred projection.

Step 3

If you have a thin glass, you can use that, but I used the throwaway plastic from scratch guard for my reflection plate. I placed it at a 45 degree angle so light from the top makes a 90 degree angle and comes straight to my eyes.

Test

To see this in action, start a slideshow of pictures on your phone and place it on top in the slot we created for phone.

Results

Wear the headset (you can put up a strap so you don't have to hold it) and look through the opening. Virtual objects will show up on the thin film we placed at 45 degrees. Brighter and contrasting images will mix well with the real world objects.

This cost me nothing, since shoe box was scrap, picked board marker from my kids desk, and a useless plastic phone screen guard (actually I used the protecting plastic from the screen guard).

Future Scope

What I learned in my experiment today is that this needs a high contrast image with a light source strong enough to counter light coming from straight ahead, otherwise the image will look blurry.

Secondly, since I am using a phone and stock images, they have a closer focus point than the rest of the world, thus you need to change focus. A quick phone app with Xamarin can help create mirrored images that will converge at a distant point and that would hopefully merge with the real world.

It is fun, give it a try!