Automating a mechanical typewriter

typewriter-driven-by-automotive-door-lock-motors

Check out all the work going on in the cabinet below this typewriter. The hack which automates a mechanical typewriter  is for an art installation, but wouldn’t it be fun to build one of these to use as a résumé printer? It really makes us wish we had an old typewriter sitting around.

It would have been much easier to patch into an electric typewriter, but we have seen the string trick used on those as well. In this case a loop of string attaches to the the bar under each key, allowing a pull from below to type the character. An automotive door lock actuator ([Harvey Moon] tells us they’re not solenoids) connects to the other end of the string for every key. But then you’ve got to have a way to drive the actuators and that’s where the protoboard full of forty relays seen to the right comes into play. That image, which was taken from the demo video after the break, shows the board being testing. We’d guess more wires are added later to multiplex the array as we can’t figure out how the Arduino manages to drive all forty of them as shown. One thing we are sure about, the completed project looks and sounds amazing!

28 thoughts on “Automating a mechanical typewriter

  1. I remember a typewriter keyboard overlay PC peripheral mentioned in Byte years ago, in the form of a box on top of a Selectric, and parallel cable to the computer. It lacked the artistic flair of these efforts.

      1. I do not know what freaked me out on the InfoWorld article. The actual device or the 64K Static ram for $995.

  2. I actually had something very similar in mind for when i have the time and find all the necessary parts.

    I did not realise i could use such actuators…. I wonder how expensive they are…

    Also i planned on using one ancient electric typewriter, where you have a single electric motor spinning a drum. In those, the keys only make a lever latch into the drum, and the momentum of the spinning drum is the one that gives you the necessary thrust. I speculate that could save me some power on the actuators, and i could get it to work faster, closer to the limits of the key levers inertia and speed.

    My biggest difficulty so far is finding enough actuators, as cheap as possible. It is not a project i have a great deal of funds for.

    Once it is done maybe i can get someone to write a printer driver for it. Possibly even with some sort of ascii-art processor in between, for non-text material. That would be cool.

    1. I bought a few at a junk yard once for $2 each, from random mid-90s, early 00 model cars. I suspect I could have paid much less.

  3. Wouldn’t it be possible to use the relays as a multiplexer? Instead of having 40 relays have 5 for the rows and 8 for the columns, in the same way as you would with a bunch of transistors.

        1. haha, well at .50c a pop, it wasn’t much of a loss. I know that mutiplexing could work, but the actuators have polarity, and initial tests with a setup like that had too may errors. When I started this project the plan was to keep it simple so that if any one part broke, it wouldn’t take down the whole system and could just be replaced easily.

          but its a more efficient idea, sure. you should try it and let me know how it goes!

  4. We built one of these in about 1981, when the only printer you could afford was a dot matrix on tractor-feed paper. Wound wire around spools, with nails to push the keys of an electric typewriter. Worked OK, pretty funky, but at least you got letter-quality results. Pretty soon the daisy wheel printers became affordable and that was the end of that.

    Nothing electronic about an electric typewriter, you know, it’s just got a mechanical motorized power assist on the keys.

  5. But when is someone going to convert a computer printer into a mechanical typewriter?
    No, I don’t mean the electronic keyboard you could attach to old Brother printers to make them become electronic typewriters.
    Headlines: Man bites Dog!

  6. Excellent stuff.
    I also had/have a vague idea to do this. I was thinking of embedding a text adventure game into it. A stand alone philosophers quest console perhaps.
    I’d also like to see more variable timing on the key strokes.

  7. I like the fact that no typewriters were harmed in this installation. Although I can’t tell what operates the carriage return. Also, what does the servo on the upright do?

    1. Thats one of the important things about this built. The typewriter is completely unaltered. The Return mechanism is run by a pulley and wire system attached to a motor and limit switch in the back. It is attached to the typewriter with a loop of string. The Shift key was attached to a servo to hold it down during a key press.

  8. This really reminds me of one of the neat antique fortune-teller machines at the Musee Mechanique on Fisherman’s Wharf, San Francisco. IIRC, that one has an unaltered Royal typewriter which is actuated in a really similar way. I think the idea is that you put in a quarter and a “ghost” types out your fortune. Awesome build!

    Jim

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