A typewriter keyboard10/4/2023 ![]() (As this article goes to press, Zylkin plans to phase the resistors out: "I'm taking your advice and moving away from resistor leads for the electrical contacts. Zylkin says that there are no easy sources for the kind of copper or phosphor-bronze strips that you can expect to use for making contacts. The only unusual step is making the leaf-spring contacts yourself by flattening the leads of two dozen half-watt resistors with two hammers or a hammer and an anvil. There's a lot of soldering (40-odd contacts plus eleven 16-pin ICs), none of it particularly fussy. "The other advantage," Zylkin notes, "is that unlike some kind of matrix, the shift registers form a repeating pattern that can be cut to any length." So regardless of how large or small your manual typewriter, his board can be chopped to fit inside with no electrical repercussions.Īssembling the kit is fairly straightforward. The shift registers take only four wires. A matrix would need fewer components and perhaps less code, but it would require either putting the microcontroller on the same board as the contacts (a tough fit inside some typewriters) or soldering more than a dozen wires between the two boards. Why use shift registers instead of the switch matrix buried within a modern keyboard? Because ordinary humans can build it. A few strategically placed magnets and reed switches detect the shift key, carriage returns, and whatever the user wants to configure as Alt or Ctrl. Then, like any other USB keyboard controller, it sends the appropriate code back to the PC. Meanwhile, the microcontroller is stepping a single logic "1" down the row of shift register pins and thus the leaf-spring contacts wired to them, letting the microcontroller detect the circuit made between the typewriter and the board. Here's how the computer attached to the typewriter knows which key has been pressed: When a letter is typed, the key's metal support bar touches a single contact on the board. The typewriter modification is based on an Atmel ATmega168 microcontroller board, a pile of shift registers, and several dozen hand-hammered leaf-spring contacts. Zylkin spent the better part of a year refining his creation at Hive76, a local workspace organized by hackers of various kinds. It's the brainchild of Jack Zylkin, a Philadelphia-based electrical engineer who has designed a kit that makes the conversion reasonably easy for anyone who enjoys hands-on projects. An obsolete manual typewriter can thus be reborn as a computer keyboard. I, too, may pass a manual typewriter on to my kids, but with a twist-a couple of circuit boards bodged to the bottom and a USB cable coming out the back. In the 1970s, she gave it to me for my high school essays. In the 1940s, my mother tapped out her college term papers on what was then a snazzy new Royal typewriter. OLD MEETS NEW: Three portable typewriters, a Royal, a Smith-Corona, and an Underwood, come out of retirement to serve as keyboards for, respectively, a Dell all-in-one computer, an iMac, and an iPad.
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