Dishwasher Notifier For The Absent-minded


[Quinn] over at BlondiHacks is admittedly pretty absent-minded when it comes to household chores such as emptying the dishwasher. She often can’t remember if the dishes are dirty or ready to be put away, so she decided it was time to devise a mechanism that would help keep her on task. She originally considered a double-sided sign that said “Clean” on one side, “Dirty” on the other, but she chose the fun option and decided to over-engineer the problem instead.

She ultimately focused on two conditions that she needed to monitor: when the dishwasher had been run, and when the dishes have been emptied. To tackle the first condition, she used a thermistor to detect when the door of the dishwasher got hot from the wash cycle. The second wasn’t quite as easy, since she often peeks into the dishwasher to grab a clean dish when needed, unloading the rest later. She eventually settled on using a tilt switch to monitor the angle of the door, assuming that the dishes have been removed if the door was open for over a minute.

[Quinn] reports that her Dish-o-Tron 6000 works well, and she had a good time building it. Sure the whole thing is kind of overkill, but where’s the fun in moderation?

28 thoughts on “Dishwasher Notifier For The Absent-minded

  1. It doesn’t wirelessly tweet status, or use any micros? I’d say it’s not quite enough overkill yet.

    I like this one though. Clean design and build, for something that could easily be done with a magnet or other indicator.

  2. I know that hacks don’t need to have a purpose, but — are you serious? You don’t need to “remember” if the dishes are clean, you just look at them. It takes about 3 seconds. And as for knowing when the cycle is done — is the dishwasher making noise? If yes the cycle isn’t done yet.

    I just fail to see how anyone, anywhere could actually consider “figuring out if the dishes are clean and if the dishwasher is still running” to be a big enough problem that it needed a complicated electronic solution…which is mounted on the door anyway so you have to be in front of the dishwasher to interact with it in the first place!

    This is such an incredible waste that it feels like some sort of april fool’s joke or overblown trolling attempt.

  3. @macw

    There are thousands of people out there, if not many more, who for reasons unknown, simply don’t remember to empty the dishwasher when it needs it. Still more who pre-wash the dishes well enough to make it difficult to tell if they’ve been run yet. I know there are lots of things that are more traumatic than finding crud in the bottom of your coffee cup when you’ve already finished the coffee, but it’s annoying.

    I applaud [Quinn] and wonder why this feature isn’t built in! Many microwaves beep until you actually get up and grab your food, thus preventing you from forgetting to eat it, a variant of this idea would be great at getting me to empty the dishwasher.

    Incidentally, I hate emptying the dishwasher worse than cleaning the litterbox and doing laundry combined. I don’t know why.

  4. Given how ridiculously unnecessary this hack is, I think I can safely say that BY FAR my favorite part is that the old palm case, painted white, looks just like a dishwasher! THAT is art! Far more than some dumb spray-paint printer bicycle or something. It’s a microcosm of the greater dishwasher whole. or some crap. :)

  5. Another problem I just remembered. If you make a habit of taking clean dishes out of the dishwasher but leaving some of them in there, sometimes someone will put dirty dishes in amongst them.

  6. WTF, I see two 555, while Quinn could have just use a single arduino. What’s wrong with her.

    jk, cool device, that I won’t replicate for now as I don’t have a dishwasher.

  7. Funny. My dishwasher has an indicator that almost does that. I found it very smart.

    When the cycle is complete (it has its own set of indicators so I know it is running), this indicator comes on and doesn’t come off until you lock the door again.

    So basically, make sure you don’t lock the door again until you have completely emptied the clean dishwasher (the door doesn’t need to be locked to stay closed.)

    Once it’s completely empty, lock the door.

    Light on? Dishes clean.
    Light off? Dishes dirty.

    I think it’s much simpler to implement, but as (pretty much) everybody here, I love an over-engineered hack. Thank you Quinn! ;-)

  8. I like that she thinks two 555s is over-complicated, when someone less experienced could easily use two arduinos to do so much less.

    A daft question, but does anyone know what kind of blue LED that is? It’s brightness looks comparable to regular red and amber ones, rather than the ridiculous super-bright blues in everything at the moment. I want to snag a few.

  9. 0. With most dishwashers, you can see if there’s soap in it, e.g. because the soap-holder lid is closed or there’s powder or gooky liquid soap around it.

    1. If there’s soap in it, it’s dirty, and you may put dirty dishes in if they fit. If it’s full, maybe run it.

    2. If there isn’t soap in it, it’s clean, and you may take clean dishes out, but may not put dirty dishes in.

    3. If there isn’t soap, and it’s empty, you can put soap in it and GOTO 1.

  10. @macw & bill
    I see what you are saying. It just does not fit our situation.
    I have 4 people that randomly remove dishes.
    2 that prewash but do not rinse the soap off.
    3 that do not remember to check the dispenser for status.
    Zero that are awake when it runs.
    No lock to show status.
    A status light (CLEAN) that turns off at the first touch of the door.

  11. Continued:
    Zero persons that want to empty the clean items.
    No ferrous surface to slap a magnet on.
    And a computer control that forgets if it wasrunning or finished!

    I love the case.
    Time to build on with a touch screen and rinse water analyzer.

    Nice build!

  12. A feature like this may seem useless but I see it as just another step in a larger picture. I imagine a central house computer wired to every outlet in the house with a small extra data port for appliances. Then appliances can register with the house computer and feed it back information like the current state of the dishes or if your stove is on.

  13. Hey everyone! Some additional follow-up…

    Regarding the blue LED, it actually is a ton brighter than the red one. I’ve got a 5k load on it, and it’s still twice as bright. I call that a feature, though. It draws your attention to the fact that work needs to be done in the area.

    Someone mentioned that it’s no better than a sign because you still have to interact with it. Actually, the whole idea is it’s completely automated and requires no internal knowledge of the machine or effort from the user. You just slap it on the door and forget about it. The problem with a sign (for me) is that you have to remember to flip it. There’s still room for absentminded error there. I wanted something that took me out of the loop completely. :)

    Also, if anyone is seriously going to build it, I’ve made some changes which I haven’t had a chance to document yet. I removed the transistor labelled “timer enable”, and switched to TTL 555s (circuit is designed for CMOS). I also put an 820pF cap in the signal line from the lower 555’s output to the upper 555’s reset. Those changes all combined fixed some glitches it was having. Occasionally it would miss a state change, or would spontaneously lose the Clean state. It seems much more solid now. I haven’t seen a bug since these changes went in. I’ll be revising the schematic and posting a “rev B” design on my website.

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