Breathing New Life Into An Old Key

For most of us who have experimented with Morse code, the oldest key we are likely to have used will have been a piece of military surplus kit from the Second World War era. [Kyle Gabriel] however is a lucky man. His grandfather left him his key-on-board telegraph practice set, a vintage key and telegraph sounder arrangement used to learn Morse code in the days when the telegraph was king. Rather than keep the set merely as an heirloom, [Kyle] set about bringing it up to date by interfacing it to a Raspberry Pi and writing a Morse reader program.

Along the way [Kyle] had to contend with debouncing the switching signal from the key, considering an RC network before settling on a software debounce timer. He provides a brief synopsis of the mechanics of Morse decoding software, and a demonstration of the code in action which you can see in the video below the break.

[Kyle’s] decoding software, beatbybeat, is on GitHub. We can see it will be a useful tool for anyone interested in Morse, or who is writing their own Morse software.

Morse code has featured on these pages more than a few times over the years. Of relevance to this piece are an Arduino decoding Morse code, a more up-to-date practice oscillator with a home-made key, and a couple of other vintage telegraphs reading RSS feeds and reading emails.

13 thoughts on “Breathing New Life Into An Old Key

  1. Nice little unit. early 20th century? Any indication where it was manufactured and by whom?

    Getting the sounder to work could be a nice feature, especially if you run it of the R-PI. Probably need to step up the voltage for that, but that should not be to much trouble.

    1. There’s no branding of any kind except the word “signal” on the sounder arm and “4 ohm” engraved in the wooden base, in front of the sounder. The closest similar model I found from an image search ( still had a minute difference of having an extra piece of hardware in front of the sounder. The description on the website says this model was manufactured between 1920 and 1930, which is when my grandfather was a kid.

      As for actuating the sounder from the Raspberry Pi, that’s a great idea for the next software update!

      1. The elevated mounting plate of the sounder also is quite interesting. Looking for KOB’s I came across several Menominee branded kits that share a lot of features with your kit. In later Signal electric units, this plate sometimes is not there it seems. Seemingly Menominee became Signal later on. Perhaps this is a date-able design element.

        Well, at least you have an idea where your key comes from!. I still have no clue how mine came into existance!

  2. Morse, at least to me, was always the ultimate coms fallback, and something I think is lost on the current crop of kids.

    Those whom had never had to deal with “less than perfect” coms, and a protocol that although slow had an equal chance of being understood (or generated) by either a man, or a machine, or both.

    It’s always been on my bucket list to be at least “literate” in Morse, and as I grew up was (kinda) important if you wanted to get into the Ham world. I still kick myself that I had a wonderful professor in college who was oldskool and was willing to take me on-foolishly, I looked at the Morse requirement, and bolted…

    I remember some of the (very) early iterations of Morse translators and generators (Trash 80s, Commodores, the occasional Sinclair) and wondered what they would make of this (the article’s focus…)

    My how things have changed-and also not changed. I love the old key-they built them well, didn’t they?

  3. Additional-recently viewed again (would that be re-viewed, reviewed, get it…groan) a movie: U571, about the (fictional) attempt to secure an Enigma coding machine during WWII. Although the story is fictional, the producers went to great lengths to make certain the tech was authentic, especially the focus (the Enigma) and that all coms were via CW, shortwave Morse, and messages had to be-well, short and to the point, and written down and decoded (or just written down…)

    I contrast that to the contact scene in “The Hunt for Red October” when the subs meet, and Ryan rattles off entire paragraphs, and the Captain of the “Dallas” says (I think):

    “I don’t know Ryan. My morse is pretty rusty-I might be sending him the dimensions of Miss October…”


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