Arduino using a straight key for Morse code assistance


For those unfamiliar with Ham Radio, there are lots of fancy tools these days to make it easier for the radio operator. But enthusiasts still like to get back to basics, and one way to do this is to participate in Straight Key Night. This is when you pull out your traditional Morse code keyer and have a chat with others around the world. The most recent event was on New Year’s Eve. The only drag is that it sometimes takes a while to find¬†another Ham who’s listening, and this can mean repetitively keying the letters QC SKN for long periods of time (QC invites listeners to respond, and SKN is to inform them you’re participating in Straight Key Night). Sure, a programmable keyer will do this for you, but that is against the spirit of the event. [Mike Herr] found a grey area by mechanically interfacing an Arduino with a straight key.

You can see the straight key being pressed by a hobby servo in the image above. The servo is driven by the Arduino, which will transmit the series of letters automatically. As you can see in the video after the break, once [Mike] hears back from a fellow operator he switches to a huge wooden straight key for the rest of the conversation.

[thanks William]


  1. Eirinn says:

    Remix pending featuring Mr GRRRRROWL.

  2. brian says:

    CQ invites a response, not QC. Amateur radio prohibits broadcast, except in the case of beacons (which are used to gauge ionosheric / atmospheric propogation conditions). Thus, if you sit down, turn on your radio, and want to talk to somebody, you will send CQ repetitively until someone answers or you move to another frequency and try again. Typically something like “CQ CQ CQ , CQ CQ CQ “. Morse operators (abbreviated CW) have a number of shorthand conventions (prosigns) as well, so the CW CQ calls can be a little more dense. I haven’t worked CW in years, so most of it escapes me – but i do recall that when a phone (voice) operator is participating in a contest, he may call “CQ Contest” or “CQ Field Day”.

  3. fred says:

    QC != CQ

  4. brian says:

    bah, tags got scrubbed from my earlier comment. Should be “CQ CQ CQ (callsign), CQ CQ CQ (callsign) (end transmission, listen for response)”

    • Ken says:

      Usually there’s a “DE” (French for “from”) before the call sign. As in “CQ CQ CQ DE AB0VV”.

      As for the project, I don’t buy the claim that using a servo eliminates any ethical problem. Might as well switch a transistor in parallel with the keyer. Not my place to judge whether it is right or wrong, though – I haven’t used Morse Code on the air for decades.

      73 DE AB0VV

  5. James says:

    Apparantly, [Mike Szczys] has never seen Contact

  6. truthspew says:

    Somebody already caught it, CQ CQ CQ DX

  7. asheets says:

    Does this lashup key at a constant speed, and does the keying sound good on the air?

  8. Richard says:

    The whole point of the straight key night is to AVOID using computerized or even mechanical help in sending the code. Though I don’t know of any hard and fast rules, this sure seems like a violation of the spirit, even if it’s creative, hack-worthy, and technically ends up using a straight key connected to the transmitter. A experienced operator can hear the difference in the timings of dits, dahs, and spaces between them. A human operating a straight key can try to keep a steady speed, but will never match the precision of any of the automated assistants commonly used.

    Is this Arduino sending out its CQ message using automatic, precisely generated dits and dahs? Or is it repeating a version that was recorded by a human using a straight key, with all of the human imperfections? The latter would at least sound more like a straight key.

    73 de AG6QR

    • Zac says:

      “a programmable keyer will do this for you, but that is against the spirit of the event”
      so, in effect, he made a programmable keyer. I’m with you that this is against the spirit, but I can still appreciate not wanting to tap for hours on end waiting for a response.

      • Ryan says:

        I don’t see it as *too* much of a violation of the spirit provided you’re not using it past making the initial connect. Been a while since I’ve done CW (or radio of any sort for that matter) and SKN seems like a fun way to get myself to do it again. However, there’s only so much to be gained by manually sending out a metric assload of CQs until you get a hit.

    • JimBob says:

      I think it would be pretty easy to program an automatic keyer with enough slack to sound human and no-one would know the difference. Who knows-maybe I already have?

  9. tytower says:

    I’ve been a ham for 40 years and keen on the key.
    Never heard of this one -I think its an add to get you to view the page.
    Successful too if it gets on Hacks

  10. tytower says:

    Hackaday put the QC bit in I think – the image says CQ

  11. gyro john says:

    The Arduino keyer and the operator’s left hand both send very nice code. Good creativity, Mike!

    73 de John, VE5BEW

  12. skiper says:

    You can use relay, mosfet, optocoupler, WHY you use servo ?

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