"You look like a Borg," people told me as I tried out head-mounted video displays for this month's column.

It wasn't just an objective observation, like saying "You look like Tom Hanks". It was a judgment on what I'd become, or was in danger of becoming: a real-life equivalent of the hapless victims from Star Trek lore whose bodies are taken over by machines.

But the goal of wearable computing isn't to make us into mindless zombies, rather it's to transform us into hyper-connected actors equipped to make more informed decisions.

Some important organisations are taking this idea seriously. Federal Express, for example, is equipping aircraft mechanics with wearable computers so they can access maintenance schedules and schematics without leaving their work stations, and the US Army's Land Warrior Program is developing wearables to keep soldiers better informed of strategies and hazards in the heat of battle.

In January Xybernaut, the company that outfitted the FedEx mechanics, introduced its first consumer product, the Poma. With wearable computing still a novelty and wearable computers mostly limited to specialised applications, it seems far-fetched to expect them to catch on for everyday use just yet. But the success of products like PDAs (personal digital assistants) hints that we may be headed in that direction.

Are you already assimilated?

Many of us carry some form of computer with us most of the time — whether it's a notebook PC, a PDA, a mobile phone, or all three.

It's a small step from keeping an intelligent device in a handy pocket or bag to wearing it on your person, and many of us would welcome the added convenience and freedom of movement — though maybe not the prospect of looking like a Star Trek baddie.

But as portable productivity devices become ever more fashionable, fashion will adapt to them.

Levis, for example, now makes a version of its Dockers pants with deep pockets for PDAs and mobile phones; and Scott EVest in the States sells a stylish, water-resistant jacket (with zip-off sleeves) that is chock-full of handy pockets for electronic gadgets and channels for routing cables such as headphone wires.

I could easily carry a cell phone, a PDA, and headphones in the model I tried out. Later, I pushed the limits by adding power adapters for the devices, a syncing cradle, and even a notebook computer. The setup wasn't extremely comfortable, but I could move around — even sit down — as easily as if I'd been lugging the gear in a backpack.

It's all on your head

Another item in my EVest was Xybernaut's Poma. Its main component is an oversized PDA running Windows CE. But instead of the familiar LCD (liquid crystal display) screen, the Poma has a cable that runs up to a colour display mounted on a silvery plastic headband. The display projects an 800x600 image on to a translucent screen that can be mounted in front of either eye: You see a ghostly image from the virtual world floating between you and the real world.

For navigation, Xybernaut provides a nifty USB optical mouse that you hold in your hand. Just slide your thumb over the glowing blue sensor to move the cursor. The process works quite well, though it doesn't feel as comfortable and precise as using a mouse or a trackball with a regular PC. The Poma also has a headphone jack and a CompactFlash slot that can accept memory cards, wireless LAN cards, and an included serial adapter for connecting to a PC.

A few glitches

So, does it all work? Somewhat. The display has to be positioned just right. If it slides a few millimetres, the image is either out of focus or just plain AWOL. To keep the display in place, I had to pull the adjusting strap to a headache-inducing level of tightness. And it was difficult to see anything in bright sunlight. I found it far easier to work with a regular PDA.

Things may improve in the future, however. I also tried a prototype display from MicroOptical that mounts on the temple of wire-frame glasses. I couldn't plug its VGA input into the Poma's proprietary display connector, but I created my own Franken-wearable by hooking it to an ultra-thin Toshiba Portege 2000 notebook in the back pocket of my EVest. The MicroOptical prototype was a bit less clunky than the Poma display and the company tells me things will get even better. It's working on a display contained entirely within glasses, like the hidden camera that Tom Cruise wears in Mission: Impossible.

To my surprise, I wasn't socially stigmatised while wearing the Poma. I wore it while commuting and shopping, and had oddly normal interactions with people I met. Of course, I am in San Francisco — where a packs of drag queens rarely get a second glance and funky new gadgets seem to appear every day.

The ears have it?

I was in the subway station, wondering why I wasn't getting more attention, when I noticed a very fashionable woman wearing her own silver headgear — a high-end set of stereo headphones.

The headphones and the head-mounted display have a lot in common. With headphones, I can augment &mdash or selectively block &mdash reality with the right sound track.

With a head-mounted display, I can add my computer desktop and wallpaper. I've been doing the low-tech version of this for a while, having nearly mastered the art of reading a book or magazine while walking to work. I say "nearly" because occasionally a helpful bystander has to grab the back of my collar to keep me from walking into traffic.

Perhaps I'd be safer with a wearable computer that uses an earphone, like the Personal Awareness Assistant concept product developed by Accenture Technology Labs. The PAA continuously listens to the sound around you and saves clips containing key phrases. If, for example, it hears the phrase "nice to meet you", the PAA will retain the chunk of conversation several seconds before and after the phrase, which likely included someone telling you their name. The folks at Accenture think this "memory augmentation", as they call it, may become a killer application for busy execs who are exposed to more information than they have time to remember or write down.

The PAA has the benefit of fitting in with gadgets we currently use: hands-free headsets have already become fashionable. And while the prototype I saw had a component that cinches around the waist like an oversize bum bag, Accenture is now working on integrating it into standard PDAs.

In addition to recording events, the PAA can be equipped with a wireless link that allows co-workers to listen in on meetings and whisper the answers to difficult questions into your ear. Owen Richter of Accenture demonstrated this feature by feeding reams of interesting stats to his colleague, Dana Le, during the presentation she gave us.

This Cyrano de Bergerac feature could come in handy, but it could also make our minds lazy. When I asked Dana, "What's eight thousand divided by three", she froze, and Owen sheepishly confessed that he didn't have a calculator running on his PC. Meanwhile, two of our editors blurted out the correct answer: 2666.67. They didn't have the benefit of memory augmentation, but they did retain the sharp math skills they'd learned in school.

I realise that wasn't a fair test. I caught Dana off guard and she may have already been a bit nervous about presenting to a bunch of curmudgeonly journalists. But this incident hints at an important lesson for the future. Whatever form they eventually take, we will be carrying (and perhaps wearing) ever more powerful computers that feed us ever more information. The challenge will be learning to use them in ways that enhance — rather than supplant — our own knowledge and reasoning skills.