You Nexus, huh? I design your eyes.

Oct 12, 2007 04:07




Yeah.  I'm sure I look like a dork (additional images: [1] [2] [3]).  I should probably explain:

After seeing this post I bought one of these - an inexpensive and flexible black-and-white head-mounted display meant to be used with a camera mounted on an R/C car.

The Cord
The cord leading out of the unit is about 31" long, which I find more than adequate.  At the end of it is a 3.5mm stereo TRS connector, which supplies video and power.  Officially, these connectors aren't supposed to be used for power connections, due to temporary shorting during insertion/removal, but this application is acceptable due to the pinout and the nature of the signals sent.  It's thin and a bit stiffer than I'd expected, but it seems pretty resilient.  Because of how it's connected to the case and logic board on the eyepiece, replacing the cable seems trivial, and I'm not concerned about having to replace the unit due to a damaged cord.

The Case
The device's case is simple, consisting of a headpiece (basically a pair of safety glasses without the lenses), a mounting bracket/hinge, and the housing for the display itself.  I find it surprisingly comfortable, and it's easy to wear for an extended period of time.  The hinge is somewhat adjustable, and provides a fair amount of motion for the eyepiece to find a comfortable place.  The hinge only mounts on the right side of the headpiece, but it seems simple enough to manufacture and I'll be attempting to build a left bracket soon.  The one thing I like least about it is the words SPY GEAR emblazoned on the front, but that can be fixed.  Before I worry about that, I'll have to focus on making a swivel for the mounting hinge(see below).

The Optics
This part is the most important, and what seems to me to be the most difficult to work with when making something like this.  Unfortunately, this is also the biggest limitation of the display.  For me at least, part of the screen is always out of focus, usually the rightmost-third.  I can move the display with my fingers to bring it into focus, but that removes the rest of the screen from focus.  I have the sneaking suspicion that being able to rotate the display in addition to the pre-existing ability to slide the display left and right would correct the problem.  I'll start experimenting with the lenses and such once I have a second unit to work with.

Power Supply and Video Adapter
I've built an adapter and power supply into an LC-1 Field First Aid Dressing Case, which handily clips onto my belt.  It holds the 3 AA (4.5v) batteries that power the unit, and has a composite video connector and a jack for the HMD's connector.  Since the HMD can apparently handle a relatively wide range of input voltages comfortably, I'm planning on adding other power options, such as USB and another combined connector I'm making specifically for wearable computing applications (that'll be another post).  Later today I'll also attempt to build an adapter to connect it to VGA ports, using the schematics found on the Linux on Obsolete Displays project page.  I'm not certain if that will provide a usable video signal or not, but it'll be interesting to experiment with nonetheless.

In a sentence:  Promising and somewhat functional, but there's room for improvement.

hardware, hmd, ubiquitous computing, user interface, head-mounted displays, wearables, wearable computing

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