PalmKey Chordic Keyboard

-- This page is still under construction. More details to appear! --

Intro:
Shortly after I got my Palm IIIx PDA, I discovered that whilst Graffiti is nice and simple for data entry into a PDA, it has 2 major problems. Even with practice getting more than 20 words per minute is difficult, and you need 2 hands to input text (if you don't have somewhere to set the PDA down, more often the not the case). Whilst surfing the web, I ran into a few sites talking about chordic keyboards. The site that first got me interested in building a chordic keyboard was the Data Egg. Other chordic keyboards out there include the Twiddler but because of the large number of buttons it was deemed impractical for something to be attached to the device or otherwise used as part of a 'wearable computer' arrangement. Details of chordic keyboards in general can be found here.

So here's my design! Its based loosely on the Data Egg idea, which was in turn based on the Microwriter which, by some sources, is apparently made by Texas Instruments. Whoever makes it, its no longer being made (last made in the early 80s from what I gather), details could be had here and here.. The alphabet is identical to that for the Microwriter with other combinations for arrow keys and other functions. The specifications are:

• Based on the MicroChip Corporation PIC16F84 microcontroller.
• Connects to the Palm through 3 lines on the connector port at the bottom (GND, DTR, DATAIN).
• Sends standard ASCII codes to the Palm using the 9600/8/n/1 serial port settings.
• Completely powered by the Palm (the 16F84 has a sufficiently wide voltage range and a low enough current draw to be completely powered by the serial port DTR line!).
• 7 keys (5 plus 2 shift) enabling 127 combinations (all keys released isn't a combination!).
• Unshifted keys identical to that for the Microwriter.
• Palm uses the KeyZ HackMaster hack which translates ASCII codes coming into the serial port into standard inputs (KeyZ was written by Jeremy Radlow and was intended to allow the Palm to be used with the Apple Newton keyboard and other serial input devices). UPDATE: The link above doesn't seem to work. I'm currently looking for the right link for KeyZ, in the meantime it should be available on most Palm software archives (www.palmgear.com should have it).

Pictures:
Pics below, I'll have the (cleaned up!) code and more details soon!
Note that these pictures were taken with an 8 year old handheld video camera and captured using the video capture utility on my video card so the quality leaves something to be desired! Better pictures when (read: if!) I finally get a digital camera ...

Original prototype (yes I have something about breadboards ;-)
1, 2, 3, 4, 5, 6, 7, 8

Second attempt, this time fully attached to the PDA
1, 2, 3, 4, 5, 6

Third (current) attempt, again attached to the PDA, this design is actually quite useable (although a little bulky - the Palm IIIx isn't small either).
1, 2, 3, 4, 5, 6, 7, 8, 9

The alphabet (I got this picture from http://www.nifty.demon.co.uk/odd/mw/index.htm but I've repeated it here as the directory structure of that site has changed twice already!).

Results:
I've not got any formal testing done but informal testing puts this input method (with the third design) at about 20wpm (typing out a few paragraphs from Time magazine and timing myself), which puts it at about the same speed as Graffiti (I would have had about 5 hours or so practice with the chordic keyboard by this time whilst I would have been Graffiti-ing for a few months). Not the speed increase I would have hoped for but the upshot is I get to keep one hand free - I can actually take notes whilst carrying books or holding pieces of paper now!

Whats next?
This project is way short of being finished - the next step (once I get some time and once I've finished updating THIS page!) is to actually make a proper attachment to the PDA (probably a piece of plastic or plastic coated metal) that follows the contours of the PDA a bit better (currently, the practicality of carrying the whole lot in my pocket is debatable). Finding a proper Palm III series connector would go some way to fixing this - if anyone knows of a source of connectors (the sort that appear on the Palm Portable Keyboards would be good!) gimme a yell at raybot @ raybot . net! I've also got to tweak the codes for special characters a bit - I keep forgetting how to type them!