Poka-Yoke
66 points by logikblok 17 hours ago | 39 comments
  • liotier 16 hours ago |
    The mainstream French word for poka yoke is "détrompeur" but I prefer its obscure and vulgar vernacular "détrompe couillon" ("couillon" has no exact English equivalent, but you might know its Italian cousin "coglione").

    Whichever name one prefers, hurray for simple interlocks that save the lives and limbs or tired inattentive operators. Dioxygen and nitrous oxide in surgical operating rooms using different connectors is a great example.

    • Y_Y 16 hours ago |
      For the benefit of others who aren't so familiar couillons, it's one of the many proud descendants of the Latin cōleus which means "balls" in the sense of testicles or courage. Other etymological cousins include the Catalan colló, the Portuguese colhão‎, and of course the notorious Spanish cojón.

      Hardly surprising these are still popular idioms.

      • beAbU 13 hours ago |
        Still not sure what the phrase means tbh.

        A direct google translation comes back with "disabuse you idiot"

        So maybe it means "idiot proof"?

        • auxym 12 hours ago |
          Yes, idiot proof would be a correct translation. Or more literally, since "détrompe couillon" is a noun, an "idiot proofer", or "idiot-proofing feature".
  • Y_Y 16 hours ago |
    I like collecting little ideas like this. Slightly meta-ironically I'd describe the genre as "just abstract enough to be useful nuggets of knowledge" and I have an org file full of them. The hard part is I don't know any better name for such "concepts" so I can't search for other people's lists.

    Does anyone else keep a similar collect or have advice for finding more?

    (For example Gurwinder sometimes posts lists like this: https://www.gurwinder.blog/p/30-useful-concepts-spring-2024 - that's what I'm talking about.)

    • tomw1808 15 hours ago |
      I have some bookmarked, but definitely not a nice list like that one, and not as many. Do you have more like these? I love to indulge into these for a few minutes a day, during commuting on the subway. I am always wondering if its because it somehow gives instant gratification into that desire to do something meaningful with the time with very little effort, ie that something new was learned (and then usually as instantly as learned forgotten :) )
    • myself248 12 hours ago |
      Wasn't that sort of the genesis of KK's Cool Tools?

      I don't know a more general name.

    • mcphage 12 hours ago |
      Somewhat related is the idea of "Mental Models"... I sometimes see list of mental models that are kinda akin to what you're describing.
    • dialup_sounds 12 hours ago |
      "concept" is the closest term with the least baggage, though I admit it's disappointingly unexciting. Perhaps the concept of concepts needs to be defined and named an eponymous law.

      "Epistemological atom" is bulky. Some are principles, some are laws, some are aphorisms, some are patterns. Sometimes you see "nuggets" or "pearls of wisdom". The publishing industry tries to froth these ideas into $25 nonfiction hardbacks, 15 minute TED talks, and hour long podcast appearances, but they are without obvious exception small ideas.

      "meme" as analogous to gene might have taken root in some alternate timeline. I think one of the characteristics that makes certain ideas compelling in this way is that they seem to be applicable in ways far beyond their origin (cf. design patterns). That's why they feel collectable.

      I liked the term "knol" for a "unit of knowledge" from when Google tried to do a wikipedia like thing. There is definitely a shape and scope relatable to a wiki page. The idea should feel unique and complete enough to have its own wiki page but dense enough to fit in the summary.

    • wheelinsupial 7 hours ago |
      I’m not sure if it’s similar to what you’re talking about, but there is something called “TRIZ” that’s a collection of “things” we were introduced to in a mechanical design class I took.

      https://en.m.wikipedia.org/wiki/TRIZ

      • eternityforest an hour ago |
        I think TRIZ applies to software in some cases too, but I usually get down voted for saying so.
  • needle0 16 hours ago |
    "Yoke" is pronounced like "yo K", not like the control wheel of an aircraft.

    (Then again, seeing how nobody pronounces Pokémon as Pokémon, I guess striving for accurate pronunciation is a lost cause)

    • dghf 15 hours ago |
      > seeing how nobody pronounces Pokémon as Pokémon

      I say (and usually hear, from English speakers) "poker mon" (non-rhotically). Isn't that roughly correct, allowing for differences between English and Japanese vowels?

      • duskwuff 7 hours ago |
        If you're going for "correct", the first two syllables should rhyme with "okay". That's what the accented é is trying to hint at.
    • Hamuko 15 hours ago |
      Pokémon is kind of an edge case considering that it's originally "Pocket Monsters" anyways (even on the retail packaging) and "Pokémon" is then derived from the Japanese abbreviation.
    • beAbU 13 hours ago |
      "Yoh kay" as in "show slay"

      Or "yoh keh" as in "moth fret"

      ?

      I pronounce pokémon as "Poh Key Mon". Which is a third variation to "ké"

      • auxym 12 hours ago |
        I'm not japanese, but in the english speaking manufacturing industry, I've heard it pronounced like "show slay", as you suggest.
      • kragen 12 hours ago |
        It depends on which dialect of English you're referring to, but either is probably close enough, especially if you speak GA or can imitate it. If you can manage "Yoh keh" as in "moth fret" in General American English it's closer.

        Japanese vowels can vary quite a lot, because there aren't nearly as many other vowels to confuse them with as there are in English.

        The Japanese "o" vowel is usually close to [ɔ], the General American English CLOTH vowel (from Wikipedia: "cough, broth, cross, long, Boston", or "moth") or THOUGHT in either GA or British Received Pronunciation ("taught, sauce, hawk, jaw, broad") than to GOAT in either dialect ("soap, joke, home, know, so, roll", or "show").

        The Japanese "e" vowel is usually close to [ɛ], which is the General American English DRESS vowel (from Wikipedia: "step, neck, edge, shelf, friend, ready", to which we might add "fret") than to [e] or [ej] or [eɪ] or [ei], which is more like the General American English FACE vowel ("tape, cake, raid, veil, steak, day", to which we might add "slay"). RP doesn't have [ɛ] at all; the closest it has is that it realizes SQUARE ("care, fair, pear, where, scarce, vary") as [ɛə].

        Other English dialects (AAVE, Irish, Scottish, Cajun, Southern American, Jamaican, Standard Indian, Bangladeshi, Nigerian, Australian) realize these vowels in their own different ways which may or may not correspond well to the Japanese phonemes you're asking about.

    • numpad0 12 hours ago |
      Calling it lost cause is a bit mean IMO, "truly accurate" pronunciation is never possible without substantial training and context switch into the target language. It's okay so long that messages go across(so key cars in place of kay cars is a bit problematic), asking for perfection is just unreasonable. Whatever the language in question might be.
  • salawat 14 hours ago |
    Also known as "eliminating the fail state" or "rendering invalid states unrepresentable".

    Unfortunately, also very attractive to being used corruptly in the political arena (see nudge theory, newspeak). Can also be downright rejected, bypassed, or ignored. See most workers/employers views on OSHA.

    • 0xbadcafebee 11 hours ago |
      Poka-yoke specifically refers to inadvertent human errors, and isn't intended to stop someone from going around it intentionally, or avoiding all failures/error states

      At my job, I add automations to try to avoid problematic and common errors. But I also engineer them so that a human can override them in the event of an emergency or some other need

  • csours 13 hours ago |
    "Anything that can go wrong, will go wrong" - Murphy

    "Dubble check that spelIng" - Muphry

    Murphy was a rocket engineer. One day their assistant plugged in a non-keyed connector upside down. It was very easy for that to go wrong.

    Another time, in another place, a rocket assembly worker hammered in a keyed connector - upside down. It was harder for that to go wrong, but, uh, life finds a way.

    • GuB-42 13 hours ago |
      "If you design something to be idiot proof, the universe will design a better idiot."
      • pornel 3 hours ago |
        This one is funny, but I don't like this saying.

        It may be interpreted in a defeatist way that poka-yoke is pointless, because it can always be defeated, but in reality improvements that save almost all "idiots" are still worthwhile.

        An interlock in the microwave doors can't stop a better idiot from disassembling it, but it prevents a lot of everyday mistakes, and that's super helpful.

    • eternityforest an hour ago |
  • Fnoord 13 hours ago |
    Reminded me of Pocoyo (English version narrated by Stephen Fry) [1]

    [1] https://en.wikipedia.org/wiki/Pocoyo

  • myself248 12 hours ago |
    In my industry, we mostly use the term to refer to mechanical features, typically keyways, that prevent connectors from being mated incorrectly.

    Suppose you have a module with 50 pins worth of connectors, but because some of the signals are in different harnesses which get installed at different times, you can't just use a 50-pin connector. For this example let's say it's sensible to break it up as 20+20+10.

    You wouldn't use two identical 20-pin connectors since they carry different signals. You probably do want to use the same family of connectors so they use common pins and have a common board footprint. So you get connectors which are the same except for having different keyways, and are often molded of different colors of plastic, by convention.

    If you've ever been working on a vehicle and seen identical-looking connectors where one's black and one's gray, look closer. Along with a color difference, there's a notch on the housing in a different place.

    This increases the number of parts that must be stocked, but the decrease in assembly errors is worth it. (And they all share the same tooling, so the manufacturing complexity isn't bad.)

    Note that this isn't required if the connectors aren't candidates for mismating in the first place. If they appear in completely different places on the harness, then it's totally fine to reuse the very same connector for the amplifier speaker signals in the trunk, and the steering column (turnsignal stalks and stuff) module signals up front. This reduces parts count without increasing errors.

    • kragen 12 hours ago |
      Worse than different signals, sometimes they carry power rails in different locations, so plugging the wrong connector in can sometimes destroy electronics or start a fire.
    • opwieurposiu 12 hours ago |
      When I was designing boards, we had 1-2 standard types of connector we were allowed use, that had an even number of pins. So we would use a different number of pins for each connector on the board, even if some of the pins were not used. It looked kind of silly to see 4 wires in a 12 pin connector but it was better then getting them mixed up.
      • myself248 11 hours ago |
        Yup, I do this myself just to reduce the number of parts I stock.

        I'll try to plan uses for all the pins in advance, like a deluxe version, and then cut down what's needed for the thing I'm doing now. Often I can actually add something useful (like an extra copy of a signal to reduce the need to splice in the harness) at no cost, just by thinking ahead a little.

        Another thing I'm proud of recently, is having an uncommitted relay on a board, whose function could then be defined by how the harness was wired. Rather than try to anticipate how it would be used, I just figured it'd be handy. Provided an extra ground too, so you could just put a hairpin wire in the connector to ground one side of the relay since that's a pretty common usage model. And for builds where we knew we wouldn't use it, just DNP at assembly time.

    • eternityforest an hour ago |
      The other solution is to make it trivial to both fix and detect errors, by using the same pinout so nothing gets damaged, and letting the computer tell you if everything is right.

      But with a car that's not really practical as things may not be accessible and easy to swap around.

  • 0xbadcafebee 12 hours ago |
    Somebody is researching Lean (or DevOps?) :) For more interesting paradigms like this one, see: https://en.wikipedia.org/wiki/Toyota_Production_System#Commo...
  • Xunxi 11 hours ago |
    The book covered a lot more ground and had some nifty illustrations.for those interested,

    https://archive.org/details/pokayokeimprovin0000unse

  • Brianwiz 11 hours ago |
    This reminds me of how the diesel spout at the gas station is too big to fit into a car that takes gasoline.
    • mikestew 5 hours ago |
      Not to big to fit in the opening of a motorcycle gas tank, as I once painfully discovered.
  • keskival 8 hours ago |
    The example is wrong:

    "A simple poka-yoke example is demonstrated when a driver of the car equipped with a manual gearbox must press on the clutch pedal (a process step, therefore a poka-yoke) prior to starting an automobile."

    You would typically put the car to a neutral gear before starting up the car, clutch isn't required.

    Furthermore, if there was such a poka-yoke preventing start-up when the clutch isn't pressed, it would prevent the common safety procedure when a car doesn't start and is in a dangerous position, for example on rails or in the motorway. In such situations you would drive the car with the starter engine alone, putting the first gear on, release the clutch, and start the car, thus moving it forward slowly by the battery and the starter engine.

    • nrr 8 hours ago |
      A lot of newer[0] US domestic market manual transmission cars do, in fact, have an interlock that prevents the starter motor from getting power without the clutch pedal also being depressed. Of particular note, my 1984 Ford Bronco II, 1991 Mitsubishi Galant, and 2004 Honda Accord all had such an interlock.

      0: This is basically everything after the three-on-the-tree/four-on-the-floor era. I have yet to drive anything with an overdrive gear that didn't require popping the clutch to crank the starter.

      • HeyLaughingBoy 5 hours ago |
        My 1987 Toyota 4x4 pickup had such an interlock. It also had a switch to disable the interlock, allowing you to start the truck in gear. A very useful feature when you were stalled on a very steep hill offroad. Starting in 1st gear, low range basically turned it into an electric car for a few seconds :-)
  • nimish 4 hours ago |
    Fall into the pit of success