Telegraph Key(singular)board: Morse for the modern era

24 Jan 2026

I acquired a telegraph key:1

Photograph of telegraph key

I turned it into a wireless Bluetooth keyboard by connecting it to an Adafruit ItsyBitsy:2

Photograph of telegraph key attached to USB power bank
Photograph of back of telegraph key, showing attached microcontroller

Never has it been more satisfying—or less private3—to type messages. Not since grade school have I been slower or had more spelling errors when typing messages.4

Photo of typed text, full of spelling errors, including “HEZ LLO WOGZ D”.

The Key(singular)board has two modes: “raw” and “alphanumeric”. In raw mode, the telegraph key’s state—pressed or unpressed—is segmented into a series of dot, dash, and space keystrokes. In alphanumeric mode, those dots and dashes are translated from Morse code into their corresponding alphanumeric character keystrokes. As a user, the raw mode acts as training wheels to calibrate against how tap durations translate into dots, dashes, and inter-tap pauses.5

One of my favorite aspects of the Telegraph Key(singular)board has been other people’s enthusiasm to give it a go. I added a quick “display incoming text” mode to the flipdots board in my apartment to turn tapping typing into a spectator sport.6

I am very, very pleased with how this project turned out, and how usable and portable my key(singular)board is.

If I were cooler, I would have typed this blog post with it. Fortunately for this post’s legibility, I did not do that. On the other hand, I’d probably be better at Morse code if I had!

Instructions for building your own Key(singular)board are here.7 Let me know if you make one!

Footnotes

  1. Thanks, Swapfest!↩︎

  2. I found this build to be satisfyingly fast and easy, because it used the same hardware and software components as various other projects I’ve done in the past few years. I wrote a bit about that process here: Learning to learn how to play with electronics.↩︎

  3. On the plus side, I suspect that most people around me don’t know Morse code, which probably gives me a certain amount of privacy through obsoletion obfuscation….↩︎

  4. Although I have not done so yet, the Key(singular)board can be used with any existing typing training software, since as far as a computer is concerned it is a normal alphanumeric keyboard.↩︎

  5. If you re-use my code, you may want to tune these hard-coded dash and dot duration thresholds to line up with your own typing speed. It would be nice to add a parameter (and a physical switch) to update this on the fly.↩︎

  6. While any keyboard can be used to update the display, using the Telegraph Key(singular)board really turns it into an Experience™. Also, there’s quite a bit of clatter.↩︎

  7. You do not need to have a telegraph key—any button will do!—but the telegraph key form factor is actively pleasing.

    If you do acquire a telegraph key—or other vintage button—learn from my mistakes and clean the button’s contacts before you start the project, so that you don’t spend a stupid amount of time trouble-shooting the rest of your otherwise trivial circuit with a voltmeter because the wired button “isn’t working”. That was the most time-consuming and frustrating part of the project, and was ultimately “solved” in five seconds with a little rubbing alcohol and a Q-Tip.↩︎