Septabmic Chording Keyers

Inspired by Greg Priest-Dorman's Chorder wiki, I'm building a handheld chorded keyboard based on Spaceman Spiff's Chording Keyboard Experiment (SpiffChorder) with some earlier influence from Steve Mann's septambic keyer. Photos and designs published in this section are licensed under the terms of the GPL (3.0), same as the SpiffChorder project itself (since they could be considered derivative work).

I started on a solderless breadboard, shown here, but those really aren't suited for higher-frequency prototyping and so I was getting stray USB device resets at random (particularly if I inadvertently brushed the ground line while not grounding myself first). I used the components in GPD's DigiKey bill of materials, going with the 8x pull-up resistor SIP array since I was only testing with 7 keys. I also chose poorly on a preformed bank of 3 yellow LEDs which were somewhat larger than I intended and the leads weren't quite a multiple of 0.1" standard breadboard pitch. I used Lady Ada's excellent AVR breadboard labels to more easily keep track of what I was connecting.

In an effort no to limit my capabilities with the keyer's software, I wanted to make sure this could double as a development board. To that end, I implemented all optional components of the SpiffChorder circuit (programming header, LEDs, pull-up resistors and screw terminals for all 8 keys and 3 modifiers). I tried to make it as compact as possible while still working on single-sided pad-per-hole perfboard, using entirely right-angle traces so as not to make stray contact with corners of square pads. Here's a top-down view showing the logical supply, ground and signal paths colored for easy identification:

This is the front showing just silkscreen markings and jumpers, as well as the traces on the back (mirrored for easier visual reference):

Monocular Headmount Displays

As I begin work on a wearable display, I'll flesh out this section. Here are some interesting links for components I'm considering:

Single-Board Wearable Computers

Right now I just go everywhere with an Asus Eee PC netbook running Debian GNU/Linux, but intend to transition soon to a low-power single-board computer. Some links for reference:

Portable Power Supplies and Chargers

Portable power will also be critical: