Mon, 21 Nov 2016


It's been three years since I updated this section of my blog, but I've got another update to publish. I have a folding bluetooth version of my Chordite now. The pictures of my MarkXVII are over on Flickr. This is 3D printed on my printer. The idea is to be able to print multiple sizes for people with different hand sizes.

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Sat, 29 Jun 2013

Mark XVI

It's been a couple of years since I updated this section of my blog, but I've finally got an update to publish. I have a folding bluetooth version of my Chordite now. The pictures of my MarkXVI are over on Flickr. This one is still made out of shapelock. I tried, without much success to have the ground wires be the frame of the keyboard, so you could bend them into the shape you want before setting it into stone with the Shapelock.

This version also has, in addition to a USB interface, a bluetoooth interface. Finally found a module that would work reasonably well with a Teensy. I've recently found one which might not even need a Teensy, but it needs more development than I want to put into it right now.

The XVII will have a 3D printed key holder, with the idea that I can measure people's hands and make them a bespoke keyboard that fits their hand well enough.

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Fri, 28 Jan 2011

Mark XV keyboard

Sigh. So little time, so many keyboards. The Mark XIV keyboard, using surface-mount pushbuttons was utter fail. Had I actually looked at them, I would have seen that they can't withstand any sideways force at all. Consequently, they break when you look at them sideways. I only discovered this after arriving in India and finding three switches completely useless. Oh well, back to the reliable Marquardt switches. Will remove the surface mount switches and replace them with the Marquardt switches.

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Mark XIV keyboard

I've given up on the Mark XIII keyboard. The problem is that the small PC board plus the brass barrier was too big to position close enough even for MY hands. I've got a Mark XIV keyboard which uses different switches (surface mount SPST very short displacement). Soldered the switches directly to the copper wires I suggested earlier, and ran wires to the bottom, weaving them into a grid holding the keyboard firmly. Got them as I wanted them and put polycapralone on both sides as reinforcement. Have a folding knuckle rest, thumb rest, and palm heel rest. It's by far the smalltest keyboard I've made so far.

I'm using a wired keyboard this time, to see how compatible I can make it. It's based on the Teensy. It's very similar to an Arduino, but it can take on a USB Keyboard flavor.

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Thu, 14 Feb 2008


Working on the Mark XIII keyboard. This one will have the keymodules connected together with a matrix of stiff-ish copper wires, covered over in polycapralone. The theory is that people will be able to change the shape of their keyboard by heating it up using a hot air blow dryer. That will soften the polycapralone, which gets quite soft, and won't hold up its own weight, hence the copper wires. The keyboard owner can push the keymodules around until they're in the perfect position for them. The copper wires will hold the shape until the polycapralone hardens, making the keyboard both flexible and stiff, soft and hard, as needed.

Here are a set of keymodules, soldered to a small PC board, with a brass strip used as a barrier against the polycapralone. Without the barrier, the polycapralone would stick to the keys and/or jam up the key movement.
Key modules (Thumbnail)

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Mon, 07 Jan 2008

Myoelectric chordite?

Stuart writes to ask if you couldn't put a strap around the wrist to sense the movement of the tendons through the wrist, by way of making a keyless chordite.

I think that would be dangerous. The tendons run inside little tunnels past the carpal bones (hence the name carpal tunnels -- oh these doctors can be SO creative sometimes). Squish the tunnels and you can inflame them. If they get inflamed they can swell up which keeps them inflamed, etc etc etc. Bad news.

No, better to go looking in the muscles further up the arm for myoelectric signals.

But note that it can be more fatiguing to be moving your fingers in mid-air than to be pressing them against something. The Chordite is designed to put the keyswitches at the finger's neutral point, so that relaxation puts your fingers on the keyswitches. It then takes only a little bit of pressure and movement to press the key, but because the key has hysteresis, you can feel it when you have pressed the key.

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Mon, 05 Nov 2007

Status report

Status report on the free chordites over in my '770' category. Readers of the main blog may be confused, but pyblosxom allows me to create multiple rss feeds. The 770 category gets syndicated on Planet Maemo. But if you only ever look in the Chordite category, you won't see it.

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Tue, 30 Oct 2007

Keycoding system

Several people have asked me what coding system is used for the Chordite. There is no standard chording system for chording keyboards, because they're all different. Some use two hands for chording. For example, Douglas Englebart's Augment used a chord keyboard and mouse combination. Hold a combination of buttons on the chord keyboard (five switches, one for each finger) and press one, two, or three mouse buttons. Or for example, the Twiddler uses a large set of buttons, three for each finger. Or I saw a fellow at a Linux World Expo who had a wrist-mounted keyboard that had four buttons under each fingertip and three under the thumb.

The Chordite has at least two possible codings. The one proposed by the inventor, John McKown, involves pressing buttons until you've gotten the correct combination of buttons, then releasing at least one button to generate that key. Another one is to use only combinations of two buttons, let's say A and B. The two of them generate four keys by changing the order in which you press and release A and B. I haven't (yet) experimented with both to see which works better.

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Thu, 06 Sep 2007

Chordite vs. Twiddler

Johan Helsingius suggests that I compare the Chordite and the Twiddler. There are two possible comparisons: between concepts and between implementations. So, the concept first.

The Twiddler uses several three keys for each finger, and two keys for your thumb. Various combinations of these keys generate keystrokes. The Chordite uses the thumb to hold the keyboard. Since the Chordite keys are pressed by the knuckles rather than fingertip, each finger may press one or two keys.

In both systems, each finger can generate two bits of information. Twiddler can press Left, Middle, Right, or no key. Chordite can press Distal, Medial, Distal and Medial, or no keys. However, the Twiddler includes two buttons for the thumb, so that makes the chordspace four times as large. The Chordite makes up for that by providing for sticky shift, control, and alt prefixes.

The implementations differ because the Twiddler 2 is a USB keyboard, and my Chordite is bluetooth. Since the Twiddler 3 will be bluetooth, there's no obvious benefit to the Chordite.

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Sun, 02 Sep 2007

Chordite versus CyKey

MJ Ray suggested that I explain how the Chordite differs or is similar to the CyKey. Well enough! Under "similar" I would put: chording, unfamiliar, pocketable, one handed, wireless, battery operated. Under "different", I would say that the CyKey must be used against a surface whereas the Chordite can be used in mid-air. The CyKey works well for either hand, whereas the Chordite is handed. The CyKey uses infrared, which restricts the positioning of the device, and which restricts the devices that may be used, whereas the Chordite uses Bluetooth, which is widely supported and doesn't require any special positioning. The CyKey's infrared is cheaper than bluetooth if you already have infrared, but is more expensive if you lack it. With the CyKey, you type with your fingertips, whereas with the Chordite, you type with your knuckles. With the CyKey your thumb moves from one key to another, whereas with the Chordite, your thumb holds the keyboard and the other fingers simply move up and down; no hunting for keys. Finally, the CyKey is an off-the-shelf product whereas a Chordite (currently) must be custom ordered to fit your hand.

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