repetitive strain injuries

I will show you briefly what RSI is in terms of using computers.
I will show you the lamentable attempts people have made to create anti RSI mouse and keyboard devices
I will explain why they are doomed to failure. They have all been designed with poor awareness of the body.
I will illustrate some of my own designs ( which work - the fact I am using them is proof of this )


Try doing a Google-Image-Search "Carpal-Tunnel". you get some fantastic pictures!

carpaltunnelMAR09.gifThe damage is usually done to the carpal tunnel in your wrist where the nerve passes through the wrist joint. The wrist, when bent back to align with the keyboard, can squeeze the nerve that runs through the wrist joint. The nerve sheath becomes inflamed and swells, which further crushes the nerve. Once started, it is very difficult to stop this cycle and repair the damage completely. Often, you have to totally give up typing for several weeks, and then wear a wrist brace to hold your wrist straight for many months until the injury is healed.

wrist.gif mouse_wrist.jpg

now I cannot find anywhere on the internet someone talking about this. so I will talk about it here.

watch a child learning to use the mouse. at first every time he tries to click the pointer moves. he has to learn to anchor the mouse with the thumb and little finger, and the heel of the hand. look at the state of the body a moment before the click is made. there is a significant tension in the arm shoulders back neck, to keep the mouse rigid - it must not move by even a single pixel. and now the click is performed; the tendon is moved while the body is straining in this posture.

there are no end of stupid devices on the market promising a solution:
lrg-sec-ErgonomicUprightMouse.jpg vertical-mouse2.jpg

hoverstop point out your arm is tense even when your hand is on the mouse but you're not using it.
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Here's a nice one:
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the obvious solution (which incidentally nobody has done) is to move the buttons on to the other hand, or a foot. suddenly the strain is gone. when my RSI got so bad that I could not even use the mouse for 10 minutes, I used a guitar footpedal to do the left clicks (like
external image pedals1.jpg
I inverted the switch so that to click I would just lift my heel off the pedal momentarily. this worked very well, but only gave one clickbutton.

so I just made a little Plasticine pad, stuck a few buttons in it and wired them up to a USB Numeric Keypad chip.

then I got scripting with AutoHotKey, which let me remap the keys to pretty much whatever I wanted. I even built in a zoom function, which simultaneously presents a magnifying glass and slows the cursor down. it is excellent for accurate clicks.
( XP sceenshot has taken out the cursor - how thoughtful of it! )

job done, problems solved. I could now use the mouse for hours.

throw in a head pointing device...

and I can move my head to move the pointer, and click with my hand. very nice.

actually, their head pointer became annoying because I had to have a little reflective patch on my cap ( you can see it in the below diagram, on the tip ) - and this was very sensitive to direct sunlight - I had to work in the dark like a vampire. so I gutted out an old gyroscopic mouse (from Gyration) and stuck the gyroscopes on the cap instead. this gives amazingly good tracking .


You might want to have a look at the YouTube video of some of this stuff

one small problem remains - it is still difficult to be very accurate - if you require a very precise click, it creates a lot of tension in the body. so I invented the 'analogue click'

this is a dust blower, wired up to a Wheatstone bridge pressure sensor, amplified and digitised
with a bit of softwareEngineering, the harder you squeeze it, the slower the mouse pointer becomes.
this is represented on screen by a circle around the cursor, which gets smaller as you squeeze harder. when it becomes a dot, the click is performed.

now I use TrackPoints instead ( the dust blower keeps depressurising and I have to inflate it with a bicycle pump ).
if you dig deep enough into the technical manuals , you discover it is possible to get a 8 bit vertical pressure readout.
What a mission that was!

okay onto the keyboard!

Yes, touch-typing promotes carpal-tunnel syndrome. this is how I got it - I used to type very fast for hours on end. ironically my dad never learned to touch type - and he is still typing away happy as larry with one finger. of course typing with one finger your wrists are in a straight line.

now again I would put some pictures in here later. but for now just imagine bringing your elbows together. when you're typing you're doing this. notice how this brings you shoulders forward, compresses your chest, rounds your shoulders, curves your back and brings your head into a hunch. now you have to lift your head up because you have to see the screen. feel the tension this is creating in your neck. laptop computers are the worst offenders. split keyboards take away a lot of this trouble.

so of course there is the obligatory mess of stupid inventions to get rid of this problem.

what I can't figure out is: if people are going to do this amount of modification to the keyboard, why not change the layout completely? seeing as the current let out is just about the worst possible layout you can imagine ... just start from scratch! qwerty is an ancient layout designed to prevent letterhead jams mechanical typewriters. it is insane people are still using it. why are they so scared of learning something new?

there are a few devices on the market which are interesting:


the inventor of this Maltron keyboard below (Stephen Hobday) was 84 when I spoke to him - he has done another designwith the keys in sensible places . I will find the picture some time . this keyboard is really nice - I tried one out once.


hoverstop - these guys seem to have ripped off the same idea

'In this day and age it is crazy that we should be having to conform to some physical device. The physical device should conform to us' Jeff Han at TED Talks: Multipoint TouchScreen Interfaces

so I wanted to get away from this idea of having a physical keyboard at a physical location, and you have to contort your body so that you can use it. I started thinking about a pad in each hand.

also my RSI was (and is) so severe that I had to resort to voice-recognition software

anyone who has tried this knows it is a total disaster. to this day I am using ViaVoice. I have tried dragon and it is no better. arbitrarily it holds my shift and control keys down, selects random chunks of text ( sometimes deleting the whole document ), repeatedly performs a random number of backspaces every time I talk, or tries to perform random system tasks. frequently it reduces me to a seething fury, and I will smash my keyboard until the keys are flying everywhere ( something like YouTube's infamous Angry German Kid ... you get the idea). then I have to find them under the bed and put them back in the keyboard. this is a soothing meditation that has yet to fail.

so I am working on some solution that combines voice-recognition together with a hand held pad. I will not be using existing voice-recognition packages - I will build a software package from a low level API, something that is usable and does not provoke rage.

YouTube Video of JediPadshows where I'm at right now.

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More Links Lots of devices here