Make Some Noise with the Typewriter Keyboard

Are you an angry programmer? Do you get the frequent urge to smash the return key or space bar after finishing every single line of code? Well then [Konstantin Schauwecker]’s typewriter keyboard is just the thing for you. In his project, [Konstantin] hacked a German Olympia Monica typewriter into a USB keyboard.

The project uses no less than 50 photo interrupters mounted on a custom PCB that mounts directly under the typewriter itself. The circuit board is so designed that the hammer arms take a position in obstructing the opto-interrupters. Every time a key is pressed, the corresponding device sends a signal to an Arduino.

In order to enable the wiring of 50 signals to an Arduino Leonardo, multiplexers and decoders are employed. CD4515, 4×16 line decoders work to activate the optical signals and the CD4067, 16×4 multiplexers are used to return the scans. This forms the traditional scanning keyboard matrix and the whole thing is managed in the Arduino code (available as a zip file).

This project can be a great starting point for anyone who wants to hack their grandpa’s old typewriter or make one in order to annoy the guy sitting next to them. Check out the video below for a demo and teardown and if you prefer Raspberry Pis then check out this mechanical typewriter hack.

11 thoughts on “Make Some Noise with the Typewriter Keyboard

  1. Talk about a key logging solution…
    I just needed to throw that out there, but yes, this is a nicely done “hack”.
    A bit trubbel some when one runs out of paper or reach end of line…
    Then talk about playing games on it, “longest” key travel in the “world”, not to mention all the jamming when trying to press more keys then one. But at least one has clicky-ish switches.

  2. I’ve seen this conversion done with a long touch sensitive resistor instead of the photo transistors. the R-strip would be used in a voltage divider, and fed to an analog-input pin of an atmega. Each key would then be some analog value.

    usbkeyboards.com uses springs as mechanical switches instead.

  3. Love it.

    They won’t get me a new keyboard at works.
    They keep getting $5 dollar ones.
    I should do this and bring it in and use it.
    I’m not far from the Boss.
    I think I would get a nice new keyboard after a week of ponding on it.

  4. And interesting and fund project to be sure.

    I don’t think the “multiplexing” scheme is very effective, as every key opto-interrupter is really wired individually.

  5. Very cool; This harkens back to the origins of the computer keyboard. The 1959 PDP-1 Used an IBM Model B Electric typewriter modified in a similar manner. It also had added solenoids to drive the typewriter as a printer. Check out Curious Mark’s video at the Computer History Museum: It even gets jammed up like a standard typewriter.

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