HMD

Often the cornerstone of a good WearComp, head-mounted displays (HMDs) can be used both to access your computer and mediate reality. It's possible to build your own HMD, and this tends to save a lot of money, but can be risky. Commercial HMDs are available, but usually extremely expensive.

HMDs are difficult to categorize, as there is a great variety of them, but one thing is for certain: there is no such thing as a perfect HMD. As HMDs are usually the most expensive and hardest to get component of a wearable computer, newbies are advised to try using an Audio-Based OS at first.

Particular HMDs documented on this wiki are in Category:HMDs.

See-Through HMDs, such as EyeTaps, are difficult to find available for purchase and extremely expensive.

=Buying an HMD= Due to the rise in popularity of HMD "theaters" for iPod video, many HMD products have become quite affordable. While these products have a level of quality difficult to achieve with a self-made HMD, virtually all of them are opaque eye masks with no in-built camera, making them only useful as portable displays, and not useful for Augmented Reality or constantly worn displays.

However, many of these devices are modifiable into one-eye non-intrusive displays, such as the Myvu Crystal.

As many of these devices use a 45° mirror mounted in front of the eye to reflect a horizontally-mounted display toward the user, it may be possible to replace this mirror with a beam-splitter to get a see-through display. Try at your own risk, but if you're successful, please document it here.

A list of HMDs can be found on the List of HMD Products page.

=EyeTaps= EyeTaps are HMDs that allow uninterrupted light flow from reality to your eye, but use a beam splitter to divert some of this light to a camera, and divert the light from a small display into your eye, to overlay reality. The term "EyeTap" was invented by Steve Mann, who is currently trying to find commercial support to mass produce these. More info is available at EyeTap.org.

=Building an HMD=

Theory
A few things I would like to cover here:
 * Explanation of EyeTap schematic - Real-World / Camera | Aremac \ Eye
 * Optics - Specifically, focusing the Aremac

Simply put, EyeTap works like this: You need a tẃo-sided mirror, a camera and a display to build Eyetap. You have a two-sided mirror diagonally in front of your right eye. Your display is on right side of the mirror so that you can see it trough the mirror. The camera goes to the left side for recording your surroundings, preferably so that it has about the same field of vision as your right eye would.

Aremac is a funny word, it is just the display. You look at the display through the mirror and computer merges input from camera and anything you want to augment it with from your computer. There are also some good illustrations of this which should clear things, like the one here. --OjM 00:57, 10 April 2009 (UTC)

MIRROR CAMERA C /  D DISPLAY _          / \          EYE

Glasses-Attached Display
Cheap, easy and relatively safe. Attaching a display to reading glasses or sunglasses is a great way to begin exploring wearable computing.
 * How-To: $25 Head Mounted Display
 * Myvu Crystal
 * Disassembling a Myvu Crystal HMD to create a one-eye HMD
 * Video of a successful build
 * MyVu Solo
 * Disasembling a MyVu Solo HMD
 * Myvu Solo disassembly

Covert Monocular Display
Covert HMDs are generally hidden inside a pair of dark sunglasses. These can be unsafe if lenses are used.
 * Good example of a covert HMD by vvortex3
 * vvortex3's HMD up close

Full HMDs

 * Steve Mann's covert EyeTap. Click the image to zoom


 * High-resolution Eyetap prototype photos

Fiber-Optic Retina Projection

 * Steve Mann's Fiber-Optic EyeTap

Other HMD Building Links

 * Visual Field Augmentation device
 * Apparently these books (by Steve Mann) describe how to build an EyeTap
 * kill-9 has an incomplete documentation of his design

Also, check out Rigs for some more designs