Running A Laundromat With An Arduino


[Hubert] sent us a tip about a friend’s project to rescue a laundromat from its failing electronics. We’re not entirely sure what went wrong with the old control center, but considering a replacement would have cost nearly 25,000 EUR, we think [Stefan] found the perfect solution: he gave it an Arduino and Android overhaul (translated).

Although [Stefan] explains that the boards were defective, perhaps one of our German readers can help us out with a more specific translation. More clear, however, are the steps taken to upgrade the system. The situation at the laundromat was a bit of an emergency: there was no way for customers to pay for use of the machines. As a result, [Stefan] had free reign to overhaul things as he saw fit. He decided to remove the complex button setup in favor of a touchscreen Android tablet, which provided users with a simple interface to make selections. The tablet serves only as an input device. The heavy lifting is handled by an Arduino Mega 2560, which hooks up to what remains of the original system and controls the 27 machines in the laundromat.

[Stefan] admits that he isn’t a particular fan of the Arduino, but that for the price, it’s a tough solution to beat. He’s not the only one overhauling with Arduinos. Check out some other examples of upgraded machines, like the Arduino-enhanced PopCARD vending machine.

UPDATE: [Andreas] sent in a better translation of the project page which we’ve included below. He worries his written English isn’t the best, but we think it is a lot easier to understand than the machine translation. Thank you for you work [Andreas!]

What went wrong, are the two main boards.

A new costumer called him “nothing is working! need help now!” the control center wasn’t working anymore. After opening the door, one can see some combined matrix circuits for the switches and LEDs. Shared column drivers aren’t that difficult in general, but the debugging is a little bit harder, especially in such a shared setup.

Both of those matrix boards had a malfunction, but because of the mostly easy principles it was easy enough to repair them. After some more research on the board, additional errors were found. Low glowing LEDs, LEDs without any lights, but electrically fully working, some at high resistance and others with a pure short circuit. Quite irritating because the owner affirmed that all the switches were working perfectly the other day.

After piggybacking some transistors the matrix circuit was working as expected with a simulated input, so the next step was the main board with the processor. To mention as a side note, that there was another similar main board. First one simply checks the coin-acceptor unit, serves / operates the switching matrix and operates the four identical relay cards.

Those are quite basic. Just some optoelectronic coupler driven by a clocked shifting register, mainly to switch the washing machines but also to get the finish status of the machines.

Those were kept completely unmodified in the later setup.

The next photos are about the washing machine and some boards for the washing powder dispenser.

Because he couldn’t reach some parts while being assembled, he had to dismantle the whole control center all night long, only to be sure, that the mainboards were completely broken. They have had undefined logic levels, floating signals, noting to fix here.

Instead of buying a new one for about 25.000 EUR he took a Arduino Mega2560 R3, which he doesn’t really like, but Arduinos are damn cheap, so whatever. So he added a self-made  simple relay shield on a prototype board to it and was almost done.

Quite funny, but replacing all the switches and LEDs with an Android Tablet was much easier, than to keep it and connect it to the Arduino, which would have had enough ports, so he would have needed to add another one for port extension and so on. But he tried to keep it simple and replacable. In first the prototype board shied hadn’t had any semiconductors on it, but he had to add them, to get rid of some additional old boards, so he could only keep the relay cards and the two mains supply circuits.

16 thoughts on “Running A Laundromat With An Arduino

  1. I’m not that much of an electronics pro like he is (thats why i use Arduino :), but it seems like in this machine the drivers (Type ULN and UDN) for the LED/Switch Matrizes were broken.
    Also, the Main Control Card with some PICs and an EEPROM were FUBAR with floating signals. As he didn’t have the program for these PICs, he decided to rip almost everything out, except working relay cards and power supply.
    Sorry, i don’t see anything more to translate :-)

    Quite interesting, replacing all these LEDs and Buttons (=> much I/O, also too much for one Arduino alone) with a simple Android Tablet and an Arduino Mega, with an stripboard-shield and an program in BASCOM.
    Also, a good KISS-style if something’s broken again, which he also had in mind, as he said.
    Relax@duino-haters, he just used an Arduino because of the price and lack of time ;-)

    1. Yes, technology marches on.

      Iv been advocating using Android tablets as cheap UIs for some time now ( ). Usually people look at me like Im a pregnant priest :o
      $50-100 buys you a 7′ responsive UI with USB host functionality and all the processing power you could ever want. But somehow everyone wants to use iPad or design their own $200 + development time one off solution.

      Loved that part :
      >I used (almost in tears!) An Arduino

      1. You’re absolutely right.
        You can’t beat the prices of China tablets, you can’t even buy the components for that price.
        But I’m still waiting for someone that manages to run realtime code on one of the cores of a 2 or 4 core ARM SOC, while Android runs on the remaining cores.
        This would give the possibility to run all of the code on the tab, and use only a dumb USB I/O card for controlling the external hardware.

        1. Let’s say you have a harddrive that requires perfect timing, and that you have something else that also requires perfect timing… Which one will get time to run? What happens when an interrupt comes in (screwing up timing)? I guess interrupts are generated for all cores on most systems, which will be the problem here. Am I right?

  2. I really don’t get the need to apologize for using Arduino, this is a perfect fit a one time replacement that need lots of hands on to replace. Time and money well saved.

  3. Bad choice removing the buttons and putting in a touch screen – How long before the touch screen is broken?

    I’m fine with adding a better display for it, but a touch screen won’t last…

      1. I think the comment is, when you see a kiosk touch screen it is usually hardened against a user getting frustrated and smashing his hand against the screen. Tablets are not designed to take that kind of abuse and would break. If everyone lightly touches the screen, then it will last 250,000,000+ touches, but one idiot who is annoyed that the machine ate his money, or that he should pay for doing his laundry and you’re nice touch screen is broken

  4. If you want a ‘tougher’ system I have several Diebold Laundry Reader and Controllers with card reader and pin pad if anyone is interested. Also Diebold Turbo Transaction Terminals and tons of electronic door locks with readers and pin pads. Doesn’t get much sturdier than the folks who make our ATMs…

    In fact, I’ve got a few pallets of hacker security hardware that needs to be used on this site! Hit me up.

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