CD Case Wearable Computer

Here's a more obvious way to wear a wearable computer:



I bought a cheap CD case, ripped out the interior CD pockets, and glued Velcro straps on the interior surface. Adhesive Velcro on the back side of the gadgets make for a configurable layout:



The case conveniently opens like a book for easy access to the components. Zipped close it becomes a compact bag that protects the interior:



Attaching a shoulder strap results in a relatively discrete wearable computer:

Shoulder Strap Wearable Computer

How do you wear a wearable computer? Here's one idea:



Each component is attached to a leather shoulder belt using Velcro. If the cables were tidied up, it might be practical, but it sure ain't subtle :)

The components are:

• a pair of Myvu Crystal video glasses hacked into a monocular head-mounted display,
• the Beagleboard single-board computer running Angstrom Linux,
• a Plexgear mini USB hub driving a bluetooth adapter and powering the Beagleboard and the display,
• four 2700 mAh AA batteries powering the USB hub,
• a foldable Nokia SU-8W bluetooth keyboard for input,
• and Internet connectivity through bluetooth tethering to an iPhone in my pocket.

Here's the system laid out on a table:

Powering the Beagleboard Using Four AA Batteries

A mobile system must be battery powered. I'd heard that the Beagleboard can be run on four regular AA batteries. My 1.2 volt batteries actually produced 5.4 volts when fully charged. I added a diode on the power cord to be on the Beagleboard's 4.8-5.2 volt safe side:



The Myvu Crystal display has a controller unit with a built-in 4h battery. It is supposed to run indefinitely while powered through the mini-USB port. But, for some reason, my unit still shut down after some time. I opened the controller and removed the battery:



I then cut the USB cable to get at the power cords:



This replaces the controller's battery with direct power from the USB cable:



Finally, I wanted to add a bluetooth adapter to the Beagleboard. Unfortunately it must be connected through an USB hub. This seems somewhat wasteful in terms of space and power consumption, but my attempts to bypass a hub by using the USB OTG port in host mode failed. Despite this, the Beagleboard, USB hub, bluetooth adapter, and Myvu Crystal display ran for a respectable 3h on my four 2700mAh batteries. Presumably you could add multiple battery packs in parallel to get an entire day of usage since each battery weighs only 30g.

Plexiglas Beagleboard Case

The Beagleboard is just an unprotected circuit board. I built the simplest possible case from a square piece of Plexiglas with four drill holes:



It was difficult to find spacer bolts of the right dimensions. Finally I cut my own from some nylon wall plugs:



Four 20mm M3 bolts are held in place by nuts on the back of the Beagleboard:

Video Cable Hack

The Beagleboard comes with an S-video port. I previously wrote about configuring it for composite video. I connected the display through an S-video to RCA and a double-male RCA adapter:



This connector is unwieldy to say the least. In fact, it's as wide as the Beagleboard itself! Using a multimeter I figured out how to solder a regular RCA connector directly onto the board. You can see where the connections go in this image, including the shorting of two soldering points using a staple:



The other end connects to the Myvu Crystal controller and the glasses. Since I'm building a monocular, I pried open the glasses' connector hoping that the second cable would be easy to remove:



The cable seems to be covered in silicone, making it hard to remove. Wire cutters to the rescue:

Wire Mount

As suggested by Raelifin, I tried mounting the display using a thick metal wire. This is what it looks like when Sanna is wearing:



One 10cm piece of 1.5mm iron wire is fastened to the glasses' frames by screws through a piece of Plexiglas. The other end is simply attached to the display with electric tape:



The mount is light weight yet surprisingly stable. Most importantly, the viewing angle is easily adjusted using a pair of pliers:



It is apparently still possible to use the phone without the display getting in the way:

Gooseneck Mount

I bought a gooseneck USB light. This is what it looked like after five minutes in my ownership:



A piece of Plexiglas was epoxied onto the neck and screwed onto the glasses' frames:



The idea was to mount the display on the flexible neck so that it could be easily adjusted to the right viewing angle:



This worked, to a degree. But the gooseneck could not be bent at any angle, so adjustment was still difficult. And the mount's weight made the glasses uncomfortable to wear.