Wearable computing

This page describes "Herbert" my wearable computer. This page has no graphics. Pictures of my wearable are available from http://www.cs.vassar.edu/~priestdo/wearable.pics.html

I have been experimenting with wearables for a while and, while there is room for improvement, I now have a setup that I am pleased with. I have taken a different approach than the folks at MIT (they have an excellent site with a lot of introductory as well as advanced material).

My approach has been driven by several factors:

Minimal dedicated hardware

While I have known for over 25 years that "some day" I would have a wearable that met my needs, I have not until recently known that that day was so close at hand. So, most of my hardware purchases were made so that I could use them in a wearable, but they could also be used "conventionally".

My primary needs are met by aural not visual output.

I would like visual output a some point but it is not essential for a goodly amount of work I need to do each day, so I have not incorporated it yet.

My expectations were based on my existing "wearable" reading technology.

I am a long time user of the 4 track 1/2 speed cassette standard that the Library of Congress adopted for it's books on tape. My efforts with wearable e-text reading machines were mostly aimed at allowing me to have the same functionality with e-text that the tape player gave me with voice recordings.

I wanted to be able to do Unix system work while walking around.

When my rig changed to be more than just a reading machine for e-text, the next thing I needed was the ability to do what I do for work while walking around. That meant Unix or linux environment, emacs and several tools. I wanted to stay with a Unix or linux machine so I could transfer files without conversion. Besides, I like Unix better than the Mac, DOS or Windows environment.

My current hardware setup consists of a Gateway Handbook, a Dectalk Express, a modified BAT keyboard, several different hand held switch sets for the BAT, a small (4 AAs) battery pack, and a set of headphones. The whole thing fits nicely in the case that came with the handbook. The BAT is attached to the outside of the bag which rests at my left hip and it is comfortable to walk and type on. If I am doing a lot of typing while walking I use one of the hand held switch sets for the BAT, I have several because I have not found the ideal one yet.

The above description is what you will see in several of the pictures on the "pics" page, however, in November '97 I moved it all into a small comercial travel bag that I have cut holes in so that I can charge and use the unit, without removing it from the bag.

I have had the handbook modified in one very important way. I have had a plug added to the case so that I can suspend and resume the handbook without opening the case by plugging in a momentary switch. This switch I added to the BAT, that way from the keyboard I can suspend and resume the handbook.

For software, I am running linux, emacs and emacspeak. This allows me to work on and in something very close to the environment I work at when physically at my office. (The only difference being linux as opposed to SunOS.)

I currently do not have wireless access, I cannot justify the expense at this time.

I chose the handbook (bought it 3 years ago) because at the time it was the lightest machine that gave me what I needed and it had just been discontinued so it was available at a very reasonable price from Gateway ($999). I have since added 16meg of ram. I had purchased an sx33 but the one time I had to send it back to Gateway for repair, they upgraded it to a dx2/50 since they couldn't find an sx33 mother board (they asked me if I would "mind" the free upgrade - go Gateway!). My primary regret is that it only has one PCMCIA slot.

I have been using a Dectalk Mulivoice for several years. I recently got the Dectalk express (smaller, lighter and speaks faster and clearer ~$1300) and I am very pleased with it. There are cheaper voice solutions, and even one alternative that is PCMCIA based, but I find I can't beat the quality of speech from the Dectalk and as a result I am able to listen faster and easer (380 - 500 wpm depending on what I am reading and what else I am doing). I hope that some day I can get speech of equal quality from software and save my self the extra weight, but until I do, I will continue to use the Dectalk.

I chose the BAT keyboard(from Infogrip - unfortunately last time I looked their web site was no longer accessible without frames) over the Twiddler(from Handykey Corp.) for several reasons.

First, the folks at folks at BAT told me (and have stood behind their word) that I could try it, learn it and then if it was not working for me, return it. I grew up in a retail store and I appreciat Infogrip's attitude.

Second, with the BAT I type with my hand "open" the pictures of the Twiddler show the hand is "closed" (the fingers curled) I believe that the open position is more relaxing over many hours of typing.

Lastly, the BAT only required a keyboard port, the Twiddler additionally needed the serial port. I only have one serial port, and that is in use for the Dectalk, so the Twiddler would have required my purchasing a PCMCIA serial card.

I did find that the keyboard port on the Handbook would not supply the BAT with the power it needed when running on battery power. Infogrip was very helpful in helping me identify the problem (and proved it was not the BAT but the handbook). What I finally did was make a small box with 4 AA hi-capacity nicads in it and a switch that lets me go from having the BAT not powered (very useful when you don't want stray clicks to matter) or have it powered by the handbook (when on AC ) or the battery pack. This switch is also on the BAT box.

The enclosure that the BAT came in was a little large. I found that the circuit board fit very nicely into a standard plastic VHS video cassette case, so, 1 hour with an exacto knife gave me a nice small case. I added a wrist rest made from an old book end which also serves a the clip to hold the unit to the handbook case.

A small thing, that does make the setup more convenient is that the headphones I am using have their own volume control. This little feature means that the Dectalk can be zipped up in the case with the handbook and I can still adjust the volume easily.

Using emacspeak is a joy, if you need text-to-speech and you want the power of Unix, this is the way to go! In fact I liked it so much, I also run the email list. This program brings the full power of emacs to the Dectalk. It is the core around which my wearable is based.

By running my sub-note with the lid closed and the screen off I quadrupled the battery life (the handbook predates the new longer life batteries). I get 3 to 4 hours work time off one battery, no power management is running on the handbook. This generally provides all the untethered wearable time I need in one day. If I want more I use an extra battery. Much more than 4 hours of continuous talking and the Dectalk battery needs a charge, if talking is intermittent the Dectalk will will keep going for most of the day.

I would like to eventually make some specialized short cables and 90degree cables to tighten up the mess in the bag, but other than that I am finding the system very pleasing.

It of course would be nice to have wireless ethernet or wireless modem and ppp, but at present I cannot justify the expense, the current setup allows me to do my work, surf (mirror the pages and then read them), read and respond to email (again off line) and then plug in the ethernet PCMCIA card and dump/send/mirror/receive the next bunch of stuff I need to work on. Of course, smaller, faster, lighter would be nice, but I have this now and it works for/with me every day.

Why bother?

In addition to my reading impairment, I have a back problem which severely limits the amount of time I can spend sitting in a chair. Much of my time in my office I must work lying on the floor which is not bad for me, but with my system-in-a-bag I can now do work while walking around which is actually good for me! It is very liberating!

Building a wearable from an existing laptop allowed me to dedicate a minimal amount of cash to the attempt (after all if it didn't work I still had a nice laptop). The only piece of equipment I purchased specifically for the wearable was the BAT keyboard. I am intrigued by the pc104 standard boards discussed at the MIT site and would eventually like to build a system using them, but in the mean time building a wearable on top of an existing sub-note got me a lot farther into the wearable world with minimum of dedicated expenses.

If you want to start playing with wearables in this way, I recommend looking for a used or referb'ed sub-note, there are quite a few 4 pound wonders out there for around $1000 that should make nice platforms for linux based wearables. Of course you should make sure it has the ports you need and that they are supported on the OS you plan to use.

I have often thought there must be a scrap heap somewhere with notebooks that have dead screens... if anybody knows where that is please let me know. I would love to save the weight and cost by purchasing a machine with a screen that wasn't there or I could remove.

Well, that's about it for an introduction to what I am using. If you have any comments or feedback, please let me know.

This page was written using emacs 19.33 and psgml mode with an HTML3.2.DTD If you have any questions or comments about it, please send them to:

This page last was mucked with on 04/21/98

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