Introduction: Wearable QWERTY Keyboard

By The 24 Hour Engineer
About: I specialize in electronics, but I can operate a band saw, ride a skateboard, and brew a tasty cuppa. I blog incessantly.

I want to make wearable and portable computing more practical, but full-size keyboards must be on-screen or carried in a backpack. Exotic models, e.g., chording keyboards, require relearning to type. A simple solution is to build something with a familiar button layout that can be worn like a guitar. Although, a keytar is more appropriate.

Supplies


[Note 1] The libraries I used are compatible with this Feather, but other models with Nordic BLE modules should work, like the Feather M0 Bluefruit.

[Note 2] I used 2mm plywood because my laser can cut it without issue, but if you have access to a metal-cutting CNC or want to cut acrylic, you should have excellent results.

[Note 3] There are so many choices for keyswitches that it is out of this project's scope to discuss them. I picked off-brand brown switches because they are relatively quiet, and I am documenting this project where other people can hear me.

[Note 4] This is not the switch I used in the project and may not fit into my footprint. Please update the drawing as appropriate.

[Note 5] I linked to the keycaps I used, but any MX-compatible set will work. The ones you choose will show off the character of your keyboard, from rounded retro to purple cyberpunk. I picked this set because it has the legends on the edges instead of the top, making it easy to see which key I want while the keyboard hangs from my shoulders.


I sanitized all the Amazon links in this article.

Step 1: Cut the Plywood

The extruded aluminum bars and the wood plates make this project's skeleton and skin. I used a 1W laser, which readily cuts 2mm plywood. Everyone knows their tools better than I can hope to cover, so I will be brief. I attached a .DXF to this step. There are small donut-shaped washers in the drawing, and you should use them to fill every nook and cranny on your build surface since you will need at least 56. The rest of the parts should have the correct copies.

Ensure you can access the terminals on the back of the LED cluster because you may have clear some material manually to solder wires later.

Once you cut everything, I recommend a layer of paint if you cut wood. I used Rust-Oleum 2X Ultra Cover, and one coat looked sufficient.

Attachments

Step 2: Assembly and Circuitry

I committed a grievous error in my design. I put the keyswitches and the microcontroller on different planes, so it is a mess trying to connect everything and keep the wires tidy. Follow the circuit schematic, and I recommend mounting the Arduino last. I used delicate 30AWG wire, so it was extra stressful because I was constantly worried that a clumsy movement would tear out my wiring, but I had ample space inside, so heavier wire might be your friend.

Install the keyswitches before you begin soldering. Make sure they are all firmly seated in their socket because if you use a thick wire to span the key's common terminal, like me, they will not reposition without resoldering.

One aluminum bar must be cut to fit in the center. Use the corner braces to affix them before installing any plywood panels.

The keyswitch circuitry is a diode-matrix, and if there is any confusion about where to attach wires, you can find the answers in the Arduino code or change pin assignments. I drilled two 1/4" (6mm) holes in the central aluminum support to pass wires.

If possible, test the code to ensure all your connections are solid because you do not want to reopen this beast. You can download the Arduino sketch from step 3.

The plywood panels connect to the aluminum via the slot nuts and M5 bolts. Use the 8mm bolts through two plywood layers and the 6mm for a single layer.

The 20mm standoffs require a short M3 bolt from the bottom and connect the top and bottom layers with an acorn nut visible on the keyboard face.

The keyboard's left side has "fencing" in the form of shaped pieces. Install them by alternating layers with the donut-shaped washer. You could cut extra and omit the spacers for a solid wall.

Install the guitar buttons on the backside with some long countersunk M3 bolts and matching slot nuts. Put the plastic caps on the three exposed aluminum ends. The handle is the last thing to install and includes the necessary hardware.

I do not have a logical order for these steps because all parts should come together at once. It took me six weeks from beginning to end to design all these parts, so I did things out of order. My experience involved redesigning ill-fitting components, adding an IO expander late in the game, and undoing assemblies rather than buying the necessary items and walking through all tidy-like.

Attachments

Step 3: Program

For users' safety, Instructables will not allow .ZIP and .7V file uploads, so it is necessary to download the 12 files from this step and put them in a folder named "Keyboardolier_2023-06-27_05"

Open your copy of Arduino IDE, and open "Keyboardolier_2023-06-27_05.ino"

Follow the Adafruit directions from their product pages if you do not have the libraries and board support for the hardware.

Connect the Arduino to your computer and upload to the board.

Pair a new Bluetooth device on your phone or computer, and select the one named, "24Eng Keyboard."

You should be ready to type!

Attachments

Step 4: Operate

This keyboard has unique function keys where you would expect to find left-hand controls if you held a keytar. The purpose is to switch modes quickly to maximize macros which you can program using the Arduino sketch. Executing common tasks with one or two buttons can become the norm, and typing can become the fallback. Unless you are a writer.

I typed this Instructable on the keyboard seen in the pictures, and I hope I have time to create a second version and fix some of the mistakes I made on this model.

Follow my blog at 24HourEngineer to see the other stuff I make and learn when I start the next iteration.