Home-made instant poka-yokes

Everyday poka-yoke

Update: Also known as Useful Landmines in the 43 Folders world – thanks Pantufla!

Mistake-proofing – poka-yoke – can be as simple as encouraging/forcing yourself to do things in a sequence, to avoid forgetting or avoiding intermediate steps. If you’re the sort of person who hangs a jacket or bag on the door handle, so it can’t be forgotten on the way out, puts things in front of the door so you can’t forget them when you’re going out, or at the top or bottom of the stairs so you’ll remember to carry them to their intended destination next time you’re using the stairs, you’re engaged in mistake-proofing. You’re introducing a behaviour-shaping constraint to assist your own effectiveness.

In the above photo, putting the mobile phone (on-charge) inside a shoe makes it more likely that it will be remembered when going out: the act of putting the shoes on requires the user to pick up the phone, which could otherwise be easily forgotten. Similarly, Mark Hurst (of Good Experience and ‘Broken’ fame) regularly features two very simple poka-yoke procedures in his Uncle Mark’s Gift Guide & Almanac:

How to remember if the batteries aren’t in your camera

Summary: If the batteries are dead, or aren’t in the camera, keep the battery compartment open.

Description: When you’re charging your camera batteries (in a wall charger, say), keep the camera’s battery compartment open. That way, if you pick up your camera to put it in your pocket or purse, you’ll see that the battery compartment is open and will remember that the batteries aren’t in it.

Leaving the camera battery door open

There’s also this:

How to make sure they see the papers you dropped off

Summary: Put the papers on their chair.

Description: Here’s a tip I learned years ago and have used ever since. If you want to make sure that someone sees the papers you dropped off at their desk, put the papers on their chair. The natural inclination is to drop the files on the keyboard, or beside the mousepad. What’s the first thing the person does when they get back to their desk? They shove the papers aside, onto a nearby pile. They want to check their e-mail immediately, and those papers are in the way!

But put the papers on their chair, and watch what happens: the person refuses to sit on them! They take a second to pick them up, and while they’re in-hand, the person takes a look at the files while they get comfortable in the chair. Bingo: you guarantee attention to your drop-off.

Papers on chair

Of course the papers-on-chair method can also be used to remind (or discipline) yourself about dealing with important papers.

This kind of very simple sequencing poka-yoke comes almost naturally in our everyday lives, at least with certain tasks. Sometimes it’s simply reminding ourselves to do something (e.g. putting a Post-It note somewhere we can see it); other times it’s trying to prevent us proceeding until some action has been taken (e.g. putting a Post-It note right in the middle of the computer screen so we can’t ignore it). Donald Norman’s Things That Make Us Smart has some interesting discussion of the power of Post-It notes and their importance as “information in the world”, disburdening some of our mental load – also part of the whole Getting Things Done phenomenon.

Sometimes we even (consciously or otherwise) try to ‘trick’ ourselves into behaving how we want to (or know we should) – the random offset alarm clock (patent; Halfbakery discussion) and Gauri Nanda’s “runaway success” Clocky being examples that spring to mind. (I once had a bedside clock radio where the button to set the minutes no longer worked, which meant that I could only set it either on-the-hour, or, because I forgot to do it at the right moment, set it maybe between 5 and 30 minutes fast. That meant that there was an uncertainty built into every time I glanced at the display, and indeed every time the alarm went off. I was rarely late, as a result.)

I have a hunch that almost trivially simple sequencing poka-yokes (in particular) could be important in designing for sustainable behaviour, such as reducing energy use and waste generation. For example, if your rubbish bin had a recycling box built into the top, so that you had to lift it out of the way (hinged, perhaps, to make it hassle to remove entirely) before putting anything into the main bin, it would be difficult to ignore the recycling box. Hence, learning as much as possible about different methods people use to mistake-proof themselves, or shape their own everyday behaviour, is likely to be useful in exapnding this line of research.

So, what are the everyday home-spun (or otherwise) tricks you use to help mistake-proof yourself?


  1. Keys on mat prevents door opening and leaving without them (provided your letter box is protected) – this has saved me countless times over the years based on the number or times I locked myself before I started doing this.

  2. Chris

    Along the same lines, if I need to remember to take something home from the office, I’ll clip my car keys to it. Can’t possibly leave those behind.

    The little ring that the keys are attached to is perfect for gripping a few important papers that need to be taken home.

  3. When you finish the last of a product, tear off the label and put it in an envelope. When you go shopping, take the envelope with you and get the items whose labels you’ve put in the envelope during the week.

  4. fool

    I used to think setting my watch fast would help, but I just adapted to it.

    Same with putting papers or letters on the dashboard of my car. I just ended up ignoring or moving them.

  5. After locking myself out of my car accidentally, I’ve started forcing myself to use the keys to lock the door from the outside, rather than pressing the power locks button. I can’t lock the keys in the car if I’m using them to lock the door!

  6. Hizzle

    I have a space heater at my desk that I really don’t want to forget to turn off when I leave for the day, for fear of catching my office on fire. So before I plug it in, I thread the cord through my key ring which has my car keys on it. That way I can’t leave until I unplug the space heater. This trick saves me a lot of “did I leave the heater on?” worrying.

  7. dvg

    The car keys are the key for me. I always leave my cell phone, wallet, whatever with my car keys, because I’m certainly not going anywhere without my car keys.

    I’m recently (re)married and still getting accustomed to wearing a wedding ring. I remove it before I take a shower because otherwise I clonk my head when I’m washing my hair. So now I tend to leave my cell phone and car keys in the bathroom — I have a cell charger there, too — and my wedding ring gets placed on top of my cell phone when I get in the shower …

  8. Adrienne

    If I’m at work and need to remember to do something when I get home, I call my home answering machine and leave myself a message to do or bring in whatever. Vice versa if I’m at home and need to remember something at work, I’ll call my office and leave myself a voicemail.

  9. Elaine

    Great poka-yokes!

    I’m trying to train myself to use all the tote bags I’ve collected over the years as my reusable grocery bags…..The challenge for me has been remembering to bring them into the store. Now I put all the totes into the biggest bag, then loop its handles over my gear shift. I’ve actually begun using the bags!

    Car keys seem to loom large in our poka-yoke culture….I place them with left-overs in the fridge at work, so I’ll remember to take them home with me.

  10. Dave

    Before I had a car with remote locking, I used to force myself to lock the car with the key from outside to prevent locking the keys in. BMW taught me this trick in the wonderful 2002 – you couldn’t lock the driver’s side door from inside; had to use the key.

    Eventually, my VW GTI did one better: the remote to lock the doors is PART OF the key – you have to have the key in-hand to use the remote. It’s a little bulky, but they’ve made the key blade fold in with a kind of switchblade action to make it about as compact as any other remote keyfob.

    When I first got together with my wife, I caused quite a few fights by putting item that needed action (small items for repair, empty bottles of things we’d used up) on the kitchen table nearest the door to the carport. She thought I was putting the stuff “in her face” because I thought she was incapable of remembering it or incompetent in some way. Took a lot of patient explanation to point out that I was putting the stuff “in my own face” so I’d remember to take action.

  11. Hizzle

    I have one more! I use my laptop at home and at work, so if I’m at work and want to remind myself of something when I get home (like “call parents”), I’ll write it on a post-it and stick to the back of my laptop screen. That way I don’t have to see it at work but I’ll definitely see it when I set up my laptop at home.

    A new one I’m trying starting today is putting my empty Gatorade bottle (which I drink at work after a long morning run at the gym) in my lunch bag after I’ve had lunch, so that when I get home and make my lunch for the next day, I’ll be reminded to put a new Gatorade in my gym bag.

    It seems like I have a lot of these poka-yokes! I guess they help me live my life as a busy and slightly scatterbrained person.

  12. When wet, I hang my umbrella on the door handle at home or on the light knob in my studio. Either way, the umbrella gets to dry out and I always remember to put the dry umbrella back in my bag on leaving.

  13. Dan

    Thanks everyone – these are some great ideas. As Elaine points out, ways to avoid forgetting keys (especially car keys) seem particularly well-represented here, but as the necessity for driving away, the keys or key-ring can also be a great ‘anchor’ for attaching other objects you don’t want to forget. It’s an interesting point.

    Thanks too to Pantufla for referring us to the Useful Landmines concept on 43Folders, which is indeed the same kind of idea expressed more elegantly, perhaps (the term poka-yoke comes from Shigeo Shingo, the Japanese manufacturing expert, and is usually applied in an engineering context rather than in everyday life). Some of the example useful landmines are simple reminders, but Merlin Mann also links to this article by Stephanie Burns which explores a number of more involved strategies, tending towards actually training oneself into a different way of behaving (‘installing new habits’), e.g.:

    You want to start carrying a bit of cash and not using your credit card.

    Make it hard to do. Freeze your credit card in a block of ice.

    You want to walk or jog each morning to start your day, but by the time you get up and move around you don’t feel like it.

    Make it easier to do. Sleep in your jogging clothes, socks included, shoes optional.

    You want to stop biting your nails, but don’t remember that ’til you’re doing it.

    Make it hard or uncomfortable to do. Coat your nails with bitters, put bandaids over the ends, put a sugar free lollypop in your mouth.

    You want the habit of waking up 20 minutes earlier but keep pushing the alarm snooze.

    Make it hard to stay in bed. Move the alarm, set the lights on a timer, set the TV on a timer.

    You want to fold the clothes, but they sit in the laundry out of sight until you walk in there next time.

    Make it easy to remember and hard to not do. Take the laundry and put it on the dining table, the lounge, in the bathroom sink.

    You want to move more, your annoyed at your inactivity.

    Make it easier to do. Take your TV remote to work and leave it there.

    A mark of a good idea is often that it arises independently in many places, under many different names. The wealth of ideas in the comments – elicited by a single blog post and a link from Good Experience (thanks, Mark) – shows just how able we are at coming up with ways to ‘fix’ our own mistakes/oversights/forgetfulness/behaviour in general.

    Keep the comments coming!

  14. If anything needs to go back into the car (like empty grocery bags or street directory), then it gets put on the floor in front of the door so that I actually have to pick them up to go out the door.

    Similarly, anything that has to be actioned outside of the house (mail etc) gets put on the floor in front of the door.

    I’ve also found that as PostIt notes often fall onto the floor (very common in humid parts of the world), I put the notes on the floor in the first place. The best place is in the doorway of a room you have to go to as part of the chore/task.

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  16. If I have piles of paper on my desk that need sorting, but I don’t have time right now/am feeling lazy/have to do something else first, I’ll often put them on my bed – then at the very latest when I want to go to sleep I am forced to do something with them. Sometimes, they’ll end up back on my desk (to repeat the game the next day), but often it’ll force me to sort them out there and then.

  17. Frank Booth

    I consider papers left on my chair to be an act of passive aggression and always move them to the bottom of my work pile.

    Direct communication with me as to the nature of the papers and your need for me to expedite them is what is expected. Failing direct communication, a short voice mail will suffice.

  18. Royce

    This one is not as foolproof as many, but it has nonetheless become one of the most useful to me. Often, I notice that I need gas while I’m in the middle of an uninterruptible errand or task. I usually have a water bottle around, so leaving one on my dash is my personal universal signal that I need to refill the gas the next time I’m in the car.

  19. Jessica

    Packing for that camping trip? Stopping by at a friends with some cold groceries? Taking wine to a dinner out? Put your car keys in the fridge with the items you don’t want to forget, and you’ll make sure you don’t leave without them!

  20. Hal

    It’s been a rainy, but not as cold as usual, winter here in NYC. Thus, I have needed to carry an umbrella, as well as wear a hat and gloves. Having left an umbrella at work a couple of times, I started putting one of my gloves or my hat on the umbrella handle, instead of in my bag. And, every time since then, I always first think, where are my gloves or hat, and when I do, I discover my umbrella!

  21. This may not work as well for those who carry handbags (but I keep my car keys in my pants pocket.) If I need to remember a bunch of things before I leave the current location, I just write them ALL on a scrap of paper and put it in the same pocket. Keys are heavier than paper, so I can’t ignore the paper when I reach for the keys. It’s a whole lot neater than stacking items, and more fool-proof than putting the keys with them, then wondering where the keys are.

  22. Jason

    Look for 3M’s Super Sticky Post-It Notes (TM and R, I’m sure). They solve the problem of notes falling off the walls and onto the floor.

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  24. officedrone

    I worked in an office where it was common practice to put papers on someone’s chair so they would know the papers had been dropped off while they were away. At my next job, I left some papers on someone’s chair my first week in the job. I stopped by a little later to check on them. “What papers?” the woman asked. I told her I’d left them on her chair. She stood up. There they were, and she was not very happy about it. Not everyone looks at their chair before sitting in it. I stopped leaving papers on chairs. I do sometimes leave them on top of keyboards.

    • Ali

      My variant of that is to leave a yellow sticky on their computer keyboard. Works great, except with those people who already put yellow stickies on their keyboards for other reasons.

  25. Chris

    I used to have a problem with getting up really late, and this post gave me some inspiration – I live in shared accommodation, so I have taken to setting two alarms; one to wake me up, and another in our shared kitchen set for ten minutes later. I have to get up in order to prevent the alarm from waking everyone else up. To date I haven’t missed one alarm 🙂 Thanks, design with intent :p

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  28. emily

    my old apartment manager charged me $40 to come unlock my apartment if i locked myself out, so after paying that twice i became an obsessive key-checker. my new apartment is a poka-yoke disguised as a building [or firetrap depending on your point of view]… the door out of my apartment has a toggle-lock on the inside, a key hole on the outside, but the door from the vestibule outside opens with keys on both sides. if i unlock my apartment door from the inside via the toggle, i can’t physically leave the building without my keys, and i can’t have locked my apartment door behind me without my keys. it’s physically impossible to forget my keys in my apartment. i’m no longer a compulsive key-checker, but now i just have to worry about finding my keys in the middle of the night in a fire… [don’t worry, i have separated the keys to the other two doors out of my apartment and have them in other locations just in case]

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