Is This The World’s Largest Dot Matrix Printer?

[RyderCalmDown] was watching a road painting vehicle lay down fresh stripes on the road one day and started thinking about the mechanism that lets it paint stripes in such a precise way. Effectively the system that paints the interspersed lines acts as a dot matrix printer that can only print at a single frequency. With enough of these systems on the same vehicle, and a little bit more fine control of when the solenoids activate and deactivate, [RyderCalmDown] decided to build this device on the back of his truck which can paint words on a roadway as he drives by. (Video, embedded below.)

Of course, he’s not using actual paint for this one; that might be prohibitively expensive and likely violate a few laws. Instead he’s using a water-based system which only leaves temporary lettering on the pavement. To accomplish this he’s rigged up a series of solenoids attached to a hitch-mounted cargo rack. A pump delivers water to each of the solenoids, and a series of relays wired to a Raspberry Pi controls the precise timing needed to make sure the device can print readable letters in much the same way a dot matrix printer works. There’s an algorithm running that converts the inputted text to the pattern needed for the dot matrix, and after a little bit of troubleshooting it’s ready for print.

Even though the printer works fairly well, [RyderCalmDown] had a problem thinking of things to write out on the roadways using this system, but it’s an impressive build based around a unique idea nonetheless. Dot matrix printers, despite being mostly obsolete, have a somewhat vintage aesthetic that plenty of people still find desirable and recreate them in plenty of other ways as well, like this 3D printer that was modified to produce dot matrix artwork.

27 thoughts on “Is This The World’s Largest Dot Matrix Printer?

  1. I saw something similar a few years ago. A guy built a self contained cart that used fuel injection valves to write with water. It has a number of text it would print but also printed out a never ending string of digits of pi.

  2. This is not a dot matrix printer, because a dot matrix printer stamps an ink filled ribbon to deposit the ink on the surface being printed on. This is more analogous to a low resolution inkjet printer that squirts droplets of ink onto the surface.

    1. That isn’t what dot matrix means, that’s just one of many method to produce a dot matrix.

      Why are you people like this on this site. Such bizarre overconfidence and the strange desire to tear down the accomplishments of others.

    2. Inkjets and laser printers are both dot matrix as well. You’re speaking of an impact dot matrix printer, which normally gets the term without any modifiers. Because all modern printers use a matrix of dots to make up the image, we adopted different terms to refer to them, but fundamentally the technology is all dot matrix.

      Daisy-wheel, Selectric-style ball, various embossing printers (like the Dymo labelers), and anything vector-based (certain laser engravers using Hershey fonts) would be the non-dot-matrix printers.

  3. If I remember correctly, Tim Hunkin made something like this years ago as demonstration on one of his “secret life of machines” series.
    If You dont know this, google it – it’s really worth watching.

    1. I immediately thought of this clip too, but can’t for the life of me find the specific episode. He never explicitly did an episode on printers, but instead had ones on photocopiers, fax machines and word processing – it’s in there somewhere. Such a shame… I’ll have to watch them again.

    1. Getting wheel-tick from the ABS tonerings would be higher resolution, but typically for applications like this you’d drag an idle wheel off the side of the vehicle and use your own encoder.

  4. Hmm, so if you used s simple scraper that lifts and drops you could.. I should not say this.. but.. you could do text with moon and mars rovers on said bodies.
    But please space going jokers, only Mars, since the local dust will remove it in a day.

    1. This is constantly reinvented, and HaD probably has 2 dozen articles on them.
      With paint and water and sand and anything esle that can be dosed and is affordable enough.

      Never saw one doing it with lines of cocaine, but that doesn’t say it didn’t happen.

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