Building A Dishwasher From Scratch

[Billy] was no fan of doing the dishes, but also found commercial solutions lacking. The options on the market simply didn’t fit his cookware and flatware. Instead of compromising, he set out to build a dishwasher of his own design. 

The build consists of a whole heap of hardware all lumped in a sizeable plastic tub. A washing machine solenoid lets water into the system, and it’s heated by an element in the base of the tub. It’s then pumped through a garden sprinkler head to give the dishes a good all-over spraying. At the end of a wash cycle, the drain pump then dumps the water to let everything dry off. An ESP8266 and a bank of relays are in place to run the show, with the user selecting wash programs via buttons and a small screen.

It may have taken a couple of years to come together, but [Billy’s] dishwasher seems to get the job done. Files are on Github for those interested, however we’d caution against attempting such a build unless you’re familiar working with plumbing and mains electricity. The other benefit of building your own dishwasher is that you’re less likely to have to patch it against widespread exploits – the security is instead up to you. Video after the break.

[Thanks to Adrian for the tip!]

48 thoughts on “Building A Dishwasher From Scratch

  1. Why didn’t I think of this? My dishwasher was the wrong size, so I bought new crockery.
    Changing the machine didn’t occur to me, but is so much a better answer.
    And I already have no apparent grounds to complain about a bad wash, as I am unable to pack it according to the manual.
    So, without buying an oval platter and a gravy ladle I can’t expect my dishwasher to work right.

    1. There is a bit of a contradiction in that manual: you are not supposed to load pointy items with the pointy bits down into the basket, but to avoid injury you should load knifes and forks with the handle up…

      1. After seeing my father get a serrated steak knife straight up under his fingernail all the way to the base of the nail, I ALWAYS load pointy side down no matter what the manual says.

      2. Having had dishwashers that make you place cutlery vertically into a basket on the lower rack in the past (and the inevitable nicks and cuts that entails) our current machine is a 12 year old Miele which does not have a basket at all – the top tray is a low-height one just for cutlery, placed horizontally. Easy to load, easy to unload. Never had any more cuts and scratches after that. I wouldn’t go back to the basket arrangement.

  2. I just love the idea of being able to look inside my running dishwasher. That alone would be enough to make a diy dishwasher.
    Can anyone tell me what the labyrinth in a dishwasher is for?

    1. Well, now I’m curious. What IS a labyrinth in a dishwasher for? None of the four I have owned in Canada/USA have one (including the most recent Bosch piece of junk).
      Drain trap? Heat exchanger? Water softener? Water re-use for conservation? Some part of the heating system?
      Do Euro dishwashers take cold water in?

      1. Actually all of above. It usually has also some kind of builtin flow meter and acts as water distribution system. Transfers the heat from and to dishwasher, depending on the cycle. There is water softener and drain trap built in. Most of the dishwashers and washing machines in Europe only use cold water and builtin electric heater. I have only seen washing machine with hot water inlet once in Europe, it was pretty exotic Daewoo bubble washing machine. In euro kitchens/bathrooms you usally have only cold water connection for appliances.

        1. Ah, thanks for the explanation. Interesting differences in water supply conventions the world ’round. One place I lived had centrally-supplied hot water to all fixtures, but it was gravity-fed from the water heater tank (“geyser”) in the attic, another was entirely point-of-use electric heaters, another was central on-demand gas-fired that was also the central heat supply, and yet another used a central heater tank, but had a continuously-running hot water circulating loop: instant hot water at every outlet. Glorious but inefficient.

          Here I have a central gas-fired water heater just a 1 m pipe run from my dishwasher. It supplies 60C water to the dishwasher from a tee ahead of the tempering valve that supplies the rest of the house 45C water. (ordinarily, these setups run around 70C in the tank, but we don’t need it that hot and it’s more efficient this way)

          The cheap, simple and efficient (but otherwise engineered-to-cost craptastic and unreliable [*]) Bosch takes in the 60C water directly: no labyrinth/matrix, and external drain trap. It does have a 700W topping heater that runs for a short while in the “sanitize” cycle. Decently efficient: 13-22L of water and < 0.3-0.6 kWh of electricity per load. Costs as much in detergent as in utilities.

          [*] two controller relay failures, one inlet valve failure, and a cracked plastic door handle in 10 years. I suppose I can't complain about the failure rate, but I can complain about the cost-cutting engineering that is the root cause of the failures.

          1. Circulating hot water is common in commercial buildings (prevents legionaires), but unheard of in residential. In the U.K., we have hot and cold from the boiler to all sinks, but appliances are almost all cold-fill only (though many kitchens / utility rooms will still have a hot feed available, at least in older houses).
            Showers are increasingly cold fill only, as they’re powered with their own heater, though some people (myself included) prefer a thermostatic shower.

          2. My Bosch is great. As I understand it, there’s a line of (more expensive) made-in-Germany Bosch dishwashers, and a (cheaper) made-somewhere-else series that still carries the Bosch brand. I paid the extra money (close to 1000AUD, but appliances are expensive here) and went for the German one. It’s been running well since 2014.

            To add to the anecdotes about hot water supplies: my Bosch dishwasher whas one inlet pipe and will accept hot or cold water, then heat if required, depending on the cycle. I have solar hot water, so it’s better to feed the dishwasher hot water, so electricity is only used to top it off.

      2. Euro dishwashers are almost exclusively cold water only. They heat way hotter than the water supply is, and they use so little water that a lot of boilers wouldn’t have run hot by the time they’ve finished filling.

        1. I think you’re highlighting a difference in hot water supply there too — the typical US domestic hot water heater maintains a large (average of 200L) tank at temperature 24/7, so hot water is pretty much always ready without delay. It can take a while to get to e.g. an upstairs bathroom, but most houses have hot water pretty much instantly in the kitchen.

          Tankless heaters are starting to become more common here, but on-demand tank boilers are pretty much unheard of.

    2. it’s not really that exciting, but i wanted to diagnose my dying dishwasher and couldn’t resist the urge to look inside. i just went to the friendly neighborhood glass shop and asked them for a piece of plexiglass of the right dimensions. i sawed off the corners to match the rounded edges on my dishwasher, and — shazam — i can see inside it while it runs. (i used a rule to jimmy the door sensor). a lot less work than making a new dishwasher :)

    3. Generally labyrinths are used as flow/pressure regulation devices. In a dishwasher, water is getting sprayed everywhere, so how do you measure the current water level accurately, or prevent the pump from sucking up air? Forcing the water through a labyrinth evens the flow out and consolidates bubbles before the water reaches the pump and the level switch.

  3. First time I ever visited Akihabara (Electric Town) in Tokyo JP, my wife pointed out one of these: In Japan dishwashers are small, table-top affairs because there’s no room to fit a typical sized dishwasher in the kitchen. I thought that was a bit extravagant. But I am so addicted to our full-size dishwasher here in the U.S. I might consider getting a Toshiba table-top model. Definitely.

    1. Watched a bit about ‘moving in Japan’ on YouTube. According to what i saw, when you rent an apartment. You often don’t get appliances, you don’t even get light fixtures. You’re expected to bring all that yourself. But also take it with you to the next place. In some ways that almost sounds preferable to the way it is around me.

  4. There’s always the bachelor method. Use one plate, one bowl, one knife, one fork, one spoon, one glass, one skillet, one saucepan. Scrub off with hot water and dry after every use. Only takes 2 or 3 minutes.

        1. I use a locality of reference based algorithm. If at someone else’s house I wash dishes like a civilized human being. If in a public dinning situation I let the minimum wage Langoliers do their thing. At home, most food is found in handy serving dishes provided by the manufacturer. The “Day After Tomorrow” approach is a last resort :P

  5. Why stop at one dish washer? Instead, replace most of your kitchen cabinets with dishwashers. Then you never have to unload the washer and put everything away. It’s all already put away!

  6. I think I might do a project, when I get the time to replace the dead control board on my old dishwasher with an esp32 to make a smart dishwasher. I did this to an old clothe washer replacing the mechanical timer with an esp8266

  7. I don’t understand how we don’t have more people DIYing controllers for domestic appliances – like we’ve got a hundred community 3D printer firmwares but zero open source 2D printers, washing machines, or dishwashers… HaD should run a challenge.

    1. I worked for a textile printing company that repurposed epson architectural printers to print onto t shirts. For a while they were just using something like a mod chip on each cartridge to fool the printer into thinking they were using the original cartridge, once I left I believe they did eventually redo the whole firmware/control board but I also believe they inked a deal directly with epson because once epson found out what they were doing they began locking them out of parts.

    2. There’s a lot of safety interlocks in consumer appliances. Ever taken apart a toaster? They’re remarkably simple devices, designed to fail safe. You do not want your dishwasher accidentally leaving the full valve on. Or the heating coils.

      Also, consumer appliances these days have a lot of efficiency stuff built in – eg dishwashers keep track of how dirty the water is and reuse it until it’s too dirty, thus reducing the amount of water they use. Anything we build is unlikely to be as efficient.

      What’s needed is a nice common interface for them to signal controls and status.

      1. “…designed to fail safe. You do not want your dishwasher accidentally leaving the full valve on”

        That craptastic Bosch I mentioned in a post above? It has a single-point failure, where if the inlet valve fails to close for any reason, it floods the house.

        The cheap-ass lowest-bidder valve that Bosch installs has a multiple single-point failure mechanisms, and wear modes that GUARANTEE it will eventually flood your house. I’m sure you can guess know how I know that.

        I bought this model in part because it has a positive physical power-off switch, since I prefer zero idle current devices and no RFI from microcontrollers waiting for you to tickle them awake. The irony is that the machine already has a level sensor and is smart enough to detect overfill and pump out excess water as needed, if only it had power…

  8. I have read and have been told by my environmentally-mindful colleagues that modern dishwashers are more water and energy efficient than hand washing, and consume less human time, my neighbors’ kid and myself spent several weekends last year gathering *empirical* data. Brand names included Whirlpool, Maytag, Samsung, and Kitchenaid – all purchased within 18 months prior to the test period of April through August of 2019.

    Electrical power and energy, water volume, plate temperature, time, dish count, dish volume, and dish mass was measured. Data was not normalized per dish count, dish volume, or dish mass, or dish type; but the kids did generate some curves that compared similar loads on different washer makes.

    Summary was that the ‘typical’ dishwasher available to the North American consumer does not offer any statistically significant energy or water savings for a household of four or greater. There were some load profiles where water consumption was typically 10% to 15% more for hand washing. For households of less than four, hand washing the ‘typical’ load consumes significantly less water, uses less energy for all load profiles, and requires less human time than a dishwasher.

    The kids submitted this as a school science project.

    1. > requires less human time than a dishwasher

      That result makes absolutely no sense unless people are pre-scrubbing everything. They probably included put-away time when considering dishwashers but not hand-washing, or some similar apples-to-oranges comparison.

    2. So, in other words, “I have read and have been told by my environmentally-mindful colleagues that modern dishwashers are more water and energy efficient than hand washing,” is a lie started by dishwasher companies, and perpetuated by tired housewives.


    3. There is *absolutely no way* that hand washing used less human time. Do your kids either think their mum sits and watches the washing machine, and so included the cycle time as “human” time? Or they totally skimped on the actual washing of the hand washing. Hand washing is bloody hard work, and takes a lot of time.
      Loading and unloading a machine takes about 2 minutes: decide if you’re doing a dark or light wash (same as for hand washing), move stuff from the (dark/light) basket into the washing machine, Chuck a scoop of powder into it, press eco mode, press start. An hour or so later, you come back and unload it, and then hang it up (which takes a few minutes, but that’s the same as hand washing).

      I’m also unfamiliar with your difference between a “typical” load and any other load. A typical load is a full load. Especially with a family. Even when I was single, I never ran the washing machine with less than a full load.

      1. Ah, whoops, I flipped to talking about washing machines.

        Dishwashers is a bit different. It really varies how people wash, but a lot of people leave the tap running. If you hand wash immediately after cooking, that can make it easier because the food isn’t dried on, and so a rinse takes it straight off. You can be sensible and decide which items need a proper wash and which can just be rinsed. If I’ve just sliced some cucumber, the knife doesn’t need to go in the dishwasher, I can just rinse it.
        It’ll also depend how much grease and burnt stuff you’ve got on your cookware. If you just eat microwave meals and sliced bread, you probably won’t save much with a dishwasher as your washing will be simple. But if you cook from scratch, cook Asian style food (stir fry = more oil, more heat, often burnt bits), bake, etc then hand-scrubbing is much harder.
        The other big advantage of a dishwasher is that (used properly) it dries the stuff, which saves a lot of time vs hand drying.

        A typical dishwasher load is still a full load though. We’ve got a family of 5, and our dishwasher is full more than once a day. Though we’ve got a euro dishwasher, which is probably smaller than a US one.

  9. Cool for sure.. but it needs more safety interlocks.. water level detection, closer monitoring of heater temperature, independent watchdog to fail safe in event of lockup, lid switch, perhaps an RCBO.. That water heater.. is it the exposed, electrified coil style? Would that make screws on outside electrified depending on what’s washed off, relative to ground?

  10. Interestingly, the top loading design is fairly similar to the first automatic dishwashers available, at least in the US — they typically had top opening doors and round racks that stacked internally. Some of them were even integral units with a sink bowl/cabinet on one side and the dishwasher door flush with the counter on the other.

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