For Those with Too Much Time on Their Hands
More than a year ago, while glancing at an article about wearable computers, I focused on a paragraph devoted to a one-hand, strap-on "keyboard." This was the Twiddler (since replaced by the Twiddler2), which, as I found out later from its Web site, resembled a small black symmetrical sweet potato attached to a long black vine and studded with 17 eyes. Now, to conform to popular usage, let's add a "k" to "eyes" and subtract an "e" to get "keys" and call the vine a "cable." (Or we can just say that the device resembles an electric hair clipper with enough controls to sculpt hair topiary.)
Having acquired the device, you will need to learn an utterly new technique in order to operate it. One key per character is pressed for letters "a" through "h," but one chord (a combination of two or more keys [Yes, music theory says that a chord is three or more notes, but this is only a bastard offspring of music theory.]) is pressed per character for all remaining characters and for actions (e.g., TAB). What really happens here is that a character or action is generated not when you press a key but when you release the key after pressing it. To generate a character/action with a chord, you release any key of the chord after pressing and holding both (or all) of the keys of the chord. Whew!
Fortunately, this is not as difficult as it may sound, but if you count it as a disadvantage, then there's one more that I should add to this short list: less speed. The manufacturer only claims a top speed of about 60 wpm versus about 150 wpm for world-class traditional-keyboard (you know, the kind that shows up in the oral tradition or, more recently, in songs by the likes of Woody Guthrie) operators. This may very well be true simply because of the lack of Twiddler2 mavens.
Now, on to the positive aspects. Though there are still a few seldom-used chords that I haven't learned, I almost immediately started learning chords by touch in conjunction with the chord decoder in the owner's manual. This is much easier to do than it is with a traditional keyboard. All the keys are within easy reach of the fingers, yet they are not so close together that they cause confusion. The 12 finger keys on the front are arranged in three columns of four so that each finger can easily reach three keys. In addition, the thumb has charge of a Trackpoint mouse equivalent as well as the NUM (for numerals), SHIFT (for uppercase), ALT (for computers that run "another" platform), and CTRL (also used with "another" platform) keys.
Hand-in-hand with the ergonomic advantage of tight key spacing there is the shape of the Twiddler2. Because of the more curled position that it puts the fingers in, it is conducive to the type of finger action customarily used in playing a string instrument (pressing rather than whacking). I know of no studies to back this up, but my best bet is that the Twiddler2 could alleviate hand and arm problems that arise from using a traditional keyboard.
That the Twiddler2 requires only one hand is an additional advantage, whether you have one hand or more than one. If you have more, I leave it to you to figure out what to do with the remaining hand(s). Though the instruction booklet, assuming two hands, advises deciding which hand to use (not necessarily the dominant one) and staying with it, I prefer to use each hand every other day.
If you ever need to take notes unobtrusively at a lecture by an evil dictator (Are there any nice ones? Maybe 0.03% of them) or maybe just by your boss, try the Twiddler2 connected to a PDA. You could easily conceal the Twiddler2 behind your back or under a jacket. Women have been known to carry more complex accouterments, so I leave further options to them.
For compatibility and, in particular, Mac friendliness, I give the Twiddler2 a rating of "very good." To back up a little: I would give the Twiddler, at most, a "good" because it required special driver software to work with a Mac. The Twiddler2, however, requires no software except when used with a PDA. Its cable terminates (why did I try to key in "terminator"?) in a PS/2 plug for computers running that "other" platform. If you get a USB adapter, then you can just plug-and-play the Twiddler2 in any recently made Mac (or recently made "other" computer). Alternatively, there is now a variant of the Twiddler2 that terminates in a USB plug. I'm uncertain about older Macs; there may be a PS/2-to-ADB adapter that will work with them.
Finally, my subjective impression is that the Twiddler2 is heaps of fun to play (that is, operate). I said "play" because, as I hinted at before, it often seems that I'm playing a mute string instrument rather than operating a keyboard.
If you want to find out more about the Twiddler2, try its Web site: www.handykey.com. Who knows? You may end up Twiddling the rest of your life away.