These pages document my project to create my version of the wearable PC (hereafter WPC for short). I intend these pages to basically be a blog, but I am writing up the initial page a little way into the project, so this first page will cover the background and the initial part of the story all as a single entry, then I will link to another page with dated blog entries in chronological order detailing the progress of the project as I go along.

Update 2007-03-19: Well it's been more than six weeks and a lot has happened. The bloggy page is here.

2007-02-02 - Background
I have been interested in the concept of a wearable computer for some time, and every now and then I look around at the available technologies to see how close such a thing might be to a practical reality. With the advent of ever smaller and more powerful portable PC hardware, it seems to me that the main stumbling blocks for usable WPCs are the human interface devices: screen, keyboard, and mouse.

Almost a year ago, I bought an OQO model 01+ and started to feel that usuable WPCs were very close now. Towards the end of 2006, I started having problems with the built-in screen of my OQO machine. This and the fact that I hadn't looked around at head- and face-mounted displays for a while prompted me to see what new options might be avilable. While they are still fairly expensive compared to conventional monitors, I was pleased to see that some of the low-end hardware had become a lot more affordable than the last time I looked, and I even found something that seemed like a viable option: the eMagin Z800 3DVisor at only US$549! Like I said, this might seem a lot for a "screen" with an 800x600-pixel resolution when compared to desktop monitors, but you just try strapping one of those babies to your head! In a sense, the 3DVisor is actually two screens: as implied by the name, it's stereoscopic, meaning it can (given the right software) display images with depth like a 3D movie. It also contain a head tracker, allowing it to monitor the motion of your head while you're wearing it. This is mostly intended to allow you to look around in 3D environments, but it can also be used as a pointing device (like a mouse with no buttons).

However, before I made the final decision to actually buy one, eMagin hiked up the price of the 3DVisor almost threefold to US$1499! This is more than I was willing to spend and I wasted no time letting eMagin know what I thought of this. Luckily, I discovered that Inition, the (only?) local distributor of the 3DVisor here in Australia, still had one unit in stock at the old price (I also saw one on feeBay, but that's another story). This was still a bit more expensive than it would have been direct from eMagin at the old price, but my whole shopping experience with Inition was a pleasure, so in the end I didn't mind paying the extra, especially since I got my 3DVisor faster than I would have if I'd had to wait for it to ship from the U.S. Incidentally, I've noticed that Inition and other distributors are not yet charging the full new price. Tek Gear published this explanation: "In order to 'soften the blow' to our customers, we will be increasing the price by about $65/day over the next two weeks in order to end up matching the eMagin MSRP". Right at this moment eMagin's own online store is not responding. In my experience this is not a rare occurrence.

While I was waiting for my 3DVisor to arrive, I decided to see if there was anything I could do about the flaky VGA connector on my OQO machine. It's difficult to get it to connect to all the pins at once, and when you finally get it working a small bump can throw it out again. I think it has always been like this since I've had it. I bought it second-hand (and without a hard drive, but that's also another story), so I suspect that the previous owner tended to wiggle the connector back and forth to remove it rather than pulling it straight out as advised by OQO. Anyway, to get at the connector in question you pretty much have to completely disassemble the OQO. I had done this before, so I wasn't too bothered, but unfortunately I got bumped while disconnecting the hard drive and put a little tear in the "flex cable" that connects the hard drive to the OQO's main circuit board. Getting a replacement cable turned out to be almost impossible. The official OQO position is that I have to

• Find someone in the U.S. to act as go-between
• Send the whole unit to that person (at my expense)
• Get them to send it on to OQO (at my expense unless this go-between owed me a favour)
• Pay the US$99 "diagnostic fee"
• Wait who-knows-how-long for them to get around to doing a job I could have done myself here in ten minutes if only I had the $5 spare part. OQO would then send the repaired unit back to the go-between (I think the $99 includes this small bit of shipping)
• Get the go-between to send it back to me (more money)

As luck would have it, however, I was exchanging emails with someone else at OQO (outside the Technical Support area) on a different matter related to the upcoming release of the new model 02. I mentioned my hard drive cable problem to this person (I don't want to say who it is in case this would get them into some sort of trouble), and they have promised to send me not one, but two replacement flex cables. They don't even appear to be asking for postage, so I offered to pay and asked if there was anything else I could do in return, but I haven't had a reply yet (it's only been about 24 hours).

The reason I mention all this is two-fold. Firstly, it has meant that I've been unable to trial the 3DVisor as a mobile display. I have tried it a little with a desktop PC and my verdict so far is that it will take a bit of getting used, but I think it's promising. Secondly, this experience has soured me even further on OQO as a company (apart from that one person), and it made me decide that I would rather avoid upgrading to their model 02. This in turn pushed me to look harder for alternatives, leading eventually to the PFU Systems Plug-N-Run modules and carrier boards, but more on them later.

I mentioned earlier that it's the whole desktop (screen, keyboard, and mouse) that poses problems for WPCs. A head-mounted display like the 3DVisor is one possible solution to the screen problem and is the path I've chosen to follow for the moment. Other solutions include wrist- and chest-mounted displays. Since my intent is to create a machine that can replace a desktop PC as completely as possible, wrist displays tend to be too small (at least so far). Chest-mounted displays are basically smallish (generally 7 or 8 inch diagonal) flat-screen monitors that are strapped to your chest while not in use and fold out somehow for viewing. In the simplest case, the screen would simply be hinged along the bottom edge and would flop down to face your eyes. This concept has some promise, but I don't like the way that it forces you to look down so that you can't see where you're going. The casual observer may think that displays like the 3DVisor block most of your field of vision, but in practice this is only true when you are looking directly "into" the display. It's quite easy to see around it just by moving your eyes and/or tilting your head a little, and in the case of the 3DVisor (and many others) it can quickly and easily be flipped up out of the way (and just as easily flipped down again). I also mentioned that the 3DVisor's head-tracking capability can be used as a pointing device, partially replacing the mouse of a conventional desktop (but without buttons). Personally, I found this method of pointing awkward, but it's certainly usable in a pinch as long as you've got some way of clicking what you point at.

During the same period that I was examining the current state of head- and face-mounted displays I was also looking for a wearable keyboard (or keyboard substitute). When I found the Twiddler2 I thought I was onto something, but looking at the pictures I thought it seemed like it would be awkward to use and would strain your hand fairly quickly. After some more poking around, I finally found John McKown's Chordite website. Even after looking at some other websites, I kept coming back to the chordite concept. If a finished product was available, I probably would have bought one the very first time I vistied the website, but I was hesitant to commit to building my own from scratch (even with the help of Mr. McKown's "downloadable information kit", which I did get the first time I visited the website). However, in the absence of anything that I considered a realistic alternative, I took the plunge. This project became quite involved, so I have given it a whole sub-section to itself, which can be found here. The only other thing I'll say about it on this page is that in addition to being a keyboard, the chordite can also be used as a pointing device. That being the case, I am not actively looking for another pointing device for this project at the moment.

If only my OQO machine were working, I would now have all the basic components to achieve my goal. On the other hand, even if I had never torn the OQO hard drive flex cable, it still wouldn't be ideal. I mentioned the internal and external display problems above. It also tends to get hotter than I would like, and the outdated Transmeta Crusoe 1GHz CPU can be a bit on the slow side. Running Kubuntu GNU/Linux rather than Windoze is probably helping, but it still bothers me enough to try to do something about it. I also mentioned that I've been put right off the idea of buying the new OQO model 02 and how that led to me finding PFU Systems. The home page of their website is a bit odd, so here's a link to a better entry point for this discussion.

PFU's Plug-N-Run modules are basically equivalent to an all-in-one motherboard for a desktop system, including the CPU, but not including the peripheral connectors like sockets for keyboard, video, and mouse; USB sockets, audio in/out sockets, etc. To get connectivity to the outside world, the Plug-N-Run module needs to be plugged into a carrier board. PFU has a small range of carrier boards available and also offers design services, etc for those wanting custom carrier boards.

The latest generation of Plug-N-Run modules (G4) currently only have one carrier board available, the "Development Board", which is about the size of a standard desktop motherboard. However, I have it on good authority that a carrier board called the "Universal LITE Carrier Board" will soon be released. This board will be similar to the SwissBlade for the previous generation of Plug-N-Run modules, but smaller (partly because of the smaller footprint of the G4B module versus the G3 module) and with lots of USB ports but no PCMCIA/CardBus or CompactFlash slots. This is really good from the WPC perspective because the CardBus slots (and to a lesser extent the CF slot too) add a lot to the overall thickness of the SwissBlade carrier.

I have exchanged a couple of emails with PFU Systems, and also with the Australian distributor, Unitronix, but apparently the guy I need to get in touch with there is on leave until next week. Since the carrier board I most likely want is not available yet, this is no problem, but I'm a little concerned that all my requests for pricing information on the older hardware have gone unanswered.

The Plug-N-Run will also need a boot/storage device and power. For portability, battery power is obviously the way to go, but the PFU carrier board has a standard 20-pin ATX power connector. This is not a new problem though, and it seems that the solution is a Mini-Box picoPSU. I haven't yet decided for sure which one I'll get, but the pico-PSU-120WI-25V is the most likely choice. For my application I could probably use an 80 or even 60 watt unit, but the price difference is not all that much and the efficiency seems to be about the same, so I might as well get the full 120W in case I have need of it in the future.

As for mass storage, I'm pretty sure that the carrier board has a 44-pin, 5V IDE interface (ie. for 2.5" laptop hard drives), as well as a SATA interface. I can currently get an 80GB 2.5" IDE drive for just under A$100 (plus shipping), so that's probably the way I'll go. I did look at "solid state" or "flash" drives, and they would definitely be the way to go if money were no object and 32GB was enough storage capacity (soon to be 64GB and 128GB, plus you can get these with both IDE and SATA interfaces, so you could easily double-up the drives for extra capacity), but personally I can't justify the expense. I haven't done so yet, but at some point I intend to look into anti-shock/anti-vibration mounting options for the hard drive.

That's it for now. I'll add that blog page as soon as I've got something new to report.