2015-11-17 (Tu) Desktop Chording Keyboard

A wrist-mounted chording keyboard is fine for typing while traveling because of its extreme portability and keys which are, by design, easy to find while typing. When desk-bound a keyboard attached to the wrist is cumbersome. The Spiffchorder was designed to be wearable but the earliest prototypes were made on a breadboard so they were flat. Desktop versions exist and a 3D printable desktop version is freely available on the site. The 3D printable model looked sleek. Rather than order switches and print a copy I decided to build one from wood. It has been a while since I got to work with wood and a wooden keyboard could be all the rage with steampunk fashions.

Enough background.

Sketching was done to brainstorm different shapes and configurations. Piano keys were a close approximation because the keys being designed were long, slender and hinged in the back rather than a square button which pushed straight down. Under each wooden key would be a modern microswitch which would be pressed by the key and the spring in the switch would be responsible for pushing the key back up.

A single #6 threaded rod would span the switches and be fastened through a wooden block similarly sized to the keys. Next to the mounting block another block would be hollowed out to hide the bolt ends. Two more threaded rods were going to go through the switch mounting holes and end the same way. There would be a block of four switches and a block of three switches to make the necessary seven switches.

 Sketch of original idea

Materials were purchased for the project. Premium lumber was chosen because it was planed on four sides and required less work to get uniform pieces which was important. 1/8" (3.175mm) brass rod was purchased instead of threaded rod or #6 bolts. Microswitches were tested on #6 threaded rod and a solid rod. Each microswitch had one hole which was meant to apply tension to a rod so it could be mounted and positioned without tools or difficult procedures. While shopping it also seemed reasonable to forgo fastening the rod as previously planned and simply block the rod with end pieces.

Materials. 1x2 premium lumber, microswitches, and 1/8" (3.175mm) brass rod

Instead of drawing a precise template on paper then translating it to wood the templating was done on a piece of wood. Going from the sketch a rough shape was drawn which gave sufficient clearance to the switch and ample leverage to press it. Each piece was rough cut to 6" (150mm). Eleven pieces were needed for seven switches and four end stops. This was reduced from 15 since the hollowed out end pieces would not be used.

Sketching template lines

Template lines and holes were transferred to four of the blocks, but mirrored. Regrettably the holes on each side were close to symmetrical so it was difficult to differentiate them. It would be logical to drill the hole in the scrappable area in a more centralized location. Holes were drilled to the same size as the brass rod and bolts long enough to touch all the pieces were inserted. The bolts were temporary and only meant to hold the pieces together while working on them.

The left side screw is in the scrappable area

With the pieces fastened together it was easy to sand the edges which weren't in the scrappable area. A belt sander was used to round the corners. The corner nearest the hinge received the most sanding and could have been rounded further but it was boring work and merely for aesthetics. The other corners were rounded just to give them a usable look. Sanding usually take place after all the sawing is done since sanding is a refinement process but in this case sanding was done earlier because the bolt in the scrappable area holds the pieces securely but will be cut away. For this reason its position is arbitrary as mentioned in the previous paragraph. After sanding the scrappable section was cut away on a band saw which shows the final shape of the wooden keys.

Sanding four keys on a belt sander

Scrappable area cut away

To do:
  • Duplicate work on the three switch array
  • Drill blind holes in end stops
  • Stain
  • Finish
    • Apply polyurethane
    • Sand/buff when dry
  • Build base
    • Construct or shape
    • Drill wiring holes
    • Stain
    • Finish
    • Attach keypads
  • Wire buttons to RJ45 connector
  • Attach to controller and test
  • Write instructions

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2

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2015-08-13 (Th)


  1. Looks like a smooth surface with comfortable, fluid operation. Be interesting how the poly layer works... not between, or it jams up! (Right? I know.. obviously) But I've learned recently your fingers can detect texture 1/70th the dia of the human hair...

  2. So, it will be interesting to see how responsive the spring- switch switch combo works. Natural... relaxed. Such a tactile input device if carefully adjusted (or adjustable?) could be revolutionary...

  3. The poly is harder than the wood and the nylon spacer between each key probably doesn't hurt.
    That's interesting about the finger sensitivity.
    Springs in the switches were considerably stiffer than a keyboard switch or a standard tactile push button but the leverage from the keys compensated nicely.
    I would say this is the opposite of revolutionary! It's more like piano keys than a typing keyboard. But if that's what people want...I'm working on a 3D printable version so people can mock one up without all the fuss of wood working.


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