What?

A mechanical keyboard, Raspberry-Pi, battery and display all in one 24" wide box. A computer you can wear! Think of it as a deck (a somewhat poorly defined computing device built from 90's hacker nostalgia) from William Gibson's Sprawl Trilogy.

It was built to make it comfortable to work in a UNIX terminal on the train. Though it turns out that staring straight down at the display isn't great long term.

Adafruit found it at Maker Fair(e)! Then Make published my blog about it(with more description of the process of building it), and BoingBoing found it too!.

What's it Made Of?

The big pieces are

• Laser cut plywood (there's a list of how many of each with the mechanicals).
• A Raspberry-Pi (a Pi 2 in v1, but anything with HDMI should work).
• A 7" 720p screen
• A Teensy 2 running a modified version of the tmk keyboard firmware and connected to the key matrix. It emulates a keyboard and mouse to the Pi.
• A 10,000 mAh LiPo battery (ripped apart and rearranged).
• Two USB hubs (one inside, one outside). WiFi and Bluetooth dongles attached inside.

How To Build One

Ping me. Twitter is easiest (use my GitHub username) and we can start an email thread.

That out of the way... the high level is:

1. Laser cut the chassis using the DXFs in mechanicals.
2. Put the switches in the plywood.
3. As this isn't made by ripping apart an existing keyboard, they keyboard bit needs to be manufactured. And because we don't have any circuit boards everything needs to be connected by wires. In this case, that means soldering 2 connections to each of the ~60 switches (and more). Bite the bullet and hand wire the key matrix. This part sucks. There are many excellent guides on assembling keyboards by hand. When I built this one, I copied from those and debugged until it worked.
4. Flash the keyboard's firmware. You'll want the tmk_keyboard/keyboard/trainboard1.5/ directory inside the firmware submodule. Follow or find instructions on building and flashing tmk to use it (the firmware itself includes a guide, so maybe start there).
5. Pull apart the battery if needed, and relocate it's charging/regulaton hardware/LEDs somewhere they are accessible from outside.
6. Bolt the battery, Pi, etc onto the bottom plate.
7. There is a top plate (which holds the switches), and a layer above that which mostly protects the edges of the keys. I glued mine together, which I think made it a bit more durable. If you'd like, you can glue together the three layers which include the handle. If you chose to glue things together, make sure to thread the bolts through to hold things in place!
8. Bolt the display between the front acrylic and the plate assembly from 6.
9. Connect the now large number of wires.
10. Slot everything together and tighten the bolts to hold it together!

Parts

The Chassis

• Plywood, acrylic, or similar. Something which can be laser cut. If you choose plywood, it should be extremely cheap. Personally I prefer the lighter weight and look of (ply)wood.
• A small section of acrylic (I chose something marketed as abrasion resistant) to cover and hold in the display.
• A display. Mine was 7" and 720p (https://www.amazon.com/gp/product/B00JOY5PGM/). You will need both the display AND a control board. I'd get both together to make sure they work together.
• A Raspberry-Pi (version doesn't matter as long as it can connect to the display)
• A battery. Again, pretty much anything works, but here's the one I used [https://www.amazon.com/gp/product/B00ITILPZ4]. At the time I chose it because it was thinish.
• A 12" HDMI cable to connect the Pi and display. If you move the Pi, changing the length might not hurt. I got my cable from Monoprice.
• Fasteners. Uhhh, need to find a list of these
• If you want to wear it, I used two of these "Guitar Strap Buttons" to attach mine to the cheapest guitar strap I could find.

The Keyboard

• Key switches for a mechanical keyboard is a whole thing. Here's a disturbingly thurough guide. There are many places to get them, but I got mine from mechanicalkeyboards.com.
• Key caps for the switches. Again, many places to get them, but mechanicalkeyboards.com works well.
• A Teensy 2.0 (https://www.pjrc.com/store/teensy.html). Other micros will work too, but if you're planning to use the tmk firmware it needs to be at ATMEGA of some sort. The Teensy 2.0 is a populat choice. Note: Newer Teensy's are much more powerful, but don't have ATMEGAs!
• Wire for the matrix
• Diodes for the matrix. I used 1N4148's but nearly anything will work (there aren't really any current or voltage constraints here). The specific ones I used are (https://www.amazon.com/gp/product/B00UXPVLEG)

Other Info

http://www.keyboard-layout-editor.com/ is a great tool for prototyping keyboard layouts. If you have an idea you want to explore, I recommend playing with it. Unfortunately I'm not sure I generated a layout for this one (I can't find it at least).

Once you've created a layout with Keyboard Layout Editor you can pour it into http://builder.swillkb.com/, which can then generate files which can be laser cut or sent out for fabrication.