Turning An IBM Selectric Into A Printer.

In the days when computers took up an entire room, a CRT monitor was a luxury. Most of the time, input and output was handled with a teletype – a typewriter connected directly to the computer. [Josh] wanted his own typewriter terminal, so he took apart an IBM Selectric II and got to work.

Instead of an electronic keyboard, the IBM Selectric II uses and electromechanical keyboard to tilt and rotate the Selectric’s typeball. In normal operation, a series of shafts underneath the keyboard are engaged. [Josh] added parts of an erector set to those levers and tied each one to one of 16 solenoids.

With a set of solenoids able to print any key with the help of an Arduino, [Josh] had a fully automated typewriter from the early 1970s. [Josh has been printing out a lot of ASCII art lately in preparation for the Kansas City Maker Faire later this month. You can check out the build videos after the break.




34 thoughts on “Turning An IBM Selectric Into A Printer.

      1. A Selectric 251 is a fictional typewriter from the TV Series Fringe. Basically a black Selectric II, which can send messages to a parallel universe. When receiving a message the typewriter works like a printer…..

  1. Looks like I was beaten to the punch! I recently acquired two of these typewriters from my mother’s attic, one functioning one not, and had almost the exact same idea. Only difference I was thinking to use a PIC18F with USB to emulate a LPT port.

  2. I also have a Selectric in my basement that was converted into a hard copy terminal. It has I believe an IEEE-488 parallel interface and was originally attached to piece of now long defunct scientific equipment.

  3. I pulled two of the typeballs from the garbage when my in-laws were sorting through stuff. No typewriter though, I’ve been trying to think of a way to maybe make a mini-graffiti bot with them, but haven’t looked into too much detail.

  4. IBM sold several versions of selectrics with various electronic I/O options, including the above-mention 2741. They also sold a printer-only version that hooked up to a punch card reader – you could encode common phrases (such as “where permitted by applicable local laws and regulations” and just jam a card in the slot to automatically type an entire line. These got hacked into early microcomputer terminals. See the articles “Taming the I/O Selectric” in the June and July 1978 issues of Kilobaud. While you’re in there, see also “Homebrew Z80 System” by then-future astronaut Norm Thagard, just for nostalgia value, in the same issues.

  5. I love the sound of the solenoids typing, its almost musical, and chango is right this thing deserves a nice case, but I vote for a clear plexiglas case, now that would be sweet.

  6. KC Maker Faire, time for that already? I didn’t budget for that, although gas price have moderated somewhat. Same weekend as Field Day. The perfect place to operate on FD, Hopefully club local to KC is doing that. Show the kiddie, and parents how the it was the radio guys that contributed to the radios many use every day to communicate. Their cell phone, WiFi etc. Does “family friendly” mean that the more off beat stuff need not apply for Maker Faire? Oh yea nice build. Stuff like that may be satisfying to get working, bit the practicability factor generally means it sees limited use, until the parts fill the bill for another project

  7. Yep, the CCCKC Amateur Radio Club members will be there in force. They are key to keeping communications working @ the faire.

    Unfortunately the call for makers (for KC) is over, so no matter how off-beat you’re out of luck in this area…but off-beat is probably just fine as long as it’s not down right offensive…join the call next year!

    And yes I will probably reuse all of the parts on this thing if it has a catastrophic failure…which it probably will. :)

  8. My grandfather’s firm had an old Wang mini with a 2741 terminal. Entering lots and lots of numbers without a 10 key was a PITA, as it was mostly used for calculating and closing traverses, a set of alt-azimuth bearings pairs and distance vector, then it would calculate the error of the closed traverse. When HP came out with the HP67, my dad could easily carry around a calculator that could do what the Wang did.

  9. Back in the day some outfit sold a device with a bunch of solenoids that fit over the keyboard of an electric typewriter (I believe it was the selectric). With it you could turn the typewriter into a printer without modifying the typewriter.

    1. This Selectric II is largely unmodified. I had to replace some old springs, but for the most part the wires simply tie into existing mechanical components…the erector set is just a gantry to provide leverage on some of the harder to reach places… Every modification can be removed…and you can still type on it…

    2. Yes, I bought one of those kits and installed it (back in ’78 I think). Worked fairly well, although would occasionally print the wrong letter. It clattered away for years on my old S110 system until I bought an Apple II and and RX80 printer.

  10. I love the Mechanical Melody as well…. and now we need to refine those sounds into various (musical) notes and start playing a symphony piece when doing a printout

  11. IIRC a Selectric has 6 (or is it 8?) bars or levers plus another one for shift that control the rotation and angle of the type ball.

    One can be turned into a keyboard (or bugged for kelogging) by mounting microswitches where those parts will close them. Add a circuit to convert those combinations to whatever your computer wants for keyboard data and you have input.

    I read about this in some magazine article in the 80’s, which mentioned that Selectrics in high security US government offices were regularly checked for modifications like that. Didn’t want the USSR’s spies knowing what CIA secretaries were typing.

    Converting a Selectric to a printer involves mounting solenoids to pull on those parts in the same combinations as they move when pressing the keys.

    It should be much simpler that what this guy did, and fit inside the original case.

    1. That’s precisely what I did, there are 6 levers to get a particular letter/symbol (and one to strike the letter). I would have put them in the case, but these cheap solenoids need gravity and an external spring to work…Also half the fun is discussing the ridiculous mechanical complexity of the original device…which doesn’t even come up in conversation unless the case is open show the thing in all it’s glory :).

      I did think about doing the micro switch concept you mentioned as well, but I didn’t really see the point after it was flipped up on edge…besides that had been done before by the zork typewriter…

      Also you can totally tell that the case for this thing is really easy to open and check for bugs…the top comes off and the whole thing hinges up clear of the bottom case…very cool design…but heavy as hell.

      Also another neat fact, the bottom case has has holes that allow access to standard 1/4 – 20 threaded holes in the inner chassis…so you can mount this thing on basically anything with $0.10 bolts…

    2. Likewise I bought one of those kits and installed it (back in ’78 I think). Worked fairly well, although would occasionally print the wrong letter. It clattered away for years on my old S110 system until I bought an Apple II and and RX80 printer.

    1. I did it this way mainly because it was the most straightforward…I didn’t want to spend time tearing it apart and attempting to get it back together, so from the outside I just had the 6 levers to actuate. Beyond that I just tried to find really cheap solenoids and then design around those once I found them.

      I don’t think I have too many unless I missed something obvious… 6 levers for key code, one to strike the ball, one for each: shift, bell, enter, space, tab and a final one for the ‘exp’ key which was more reliable at performing a carrage return. So thirteen in the final build. Originally I planned to do backspace and index keys as well, but didn’t need them.

  12. I built an interface and driver for my BBC micro to use an ex-bank IBM selectric printer back in 1982/3 – use to shake the table when operating, and it was LOUD; but much cheaper than a dot matrix in those days!

  13. I used to build IBM Selectrics from the frame up , all day long at a work bench and then did field service for many years … I still take one out in the garage strip it down to bare frame and build it back up every now and then , just for grins . I converted alot of the commercial interfaced machines into desktop machines .. the interfaced machines had case hardened cams (the cams were diff colored than desktop) and the latches were hardened more as well to help them take the constant beating . Radio Electronics published a good series with templates for installing the servos for the latches etc . 5 latches for charachter selection , and then the function latches … best piece of precision machinery ever made .

  14. I believe I had a few articles published someplace on this very subject . I made a few dozen of them and maintained many . You’ll most likley find my initials on the frames and cases of hundreds and hundreds of selectrics and even earlier typebar model C and D machines around Kansas City and possibly other areas since we reconditioned to a dealer network .

  15. I had an idea similar to this recently when I came across some old kit I have tucked away in a closet collecting dust. I thought how cool would it be to have a teletype machine to connect this to without shelling out $500 for a vintage ASR33. I was wondering if it might be possible to convert a newer electric typewriter with discrete logic that wouldn’t involve me fitting any extra mechanical equipment. Maybe an MCU to read out key presses and send it back to the computer over RS232?

  16. Wow! This has been really interesting to look at.
    In 1968, I was granted US Patent # 3,413,624 for “Automatic Magnetic Recording and Playback Control System for a Keyboard Actuated Business Machine” (applied for in 1964). It used a Selectric typewriter as the input and output for a magnetic tape recording machine for the reproduction of letters. Come a long way since then. It would be fun to drag out one of the old models and combine it with an Arduino to reconstruct some of the old stuff. But, no, I will not do that.

  17. “Back in the day some outfit sold a device with a bunch of solenoids that fit over the keyboard of an electric typewriter (I believe it was the selectric). With it you could turn the typewriter into a printer without modifying the typewriter.”

    I actually think people would buy a gadget like what you are describing. There are people out
    there who want a typewritten look without the hassle of an erector set. Plus, so many people
    are tired if high priced ink. Just word processing –that’s fine with me?

  18. I did this in 1980 because there was no “letter quality” printer back then.
    Building a simple parallel interface to the selectric electronics was a lot easier.
    It is very simple data stream as I remember.

  19. This was fun to see. Great work!

    It brings back old memories for me. In the late 1970s, early 1980s I was developing a keyboard design (US Patent # 4,265,557) that would wrap the keys up around the typist’s fingers – the idea was to increase typing speed and accuracy, because the keys would already be touching your fingers, and when you began the motion you would ordinarily use to type a key off the ‘home row’ the key would pick up your motion with a fraction of it’s former motion.

    (If anyone actually looks up the patent, please ignore the mess of little levers in the lower-left portion of the main patent drawing. They are based on a goofy misunderstanding of the workings inside the typewriter, and miscommunication with the draftsman – they have nothing to do with the actual idea.)

    In order to experiment with this, I bought a used IBM Selectric I/O unit – it had the solenoids built in – and figured out how to wire it up to type the letter corresponding to the little switch under each key on my keyboard. I have little knowledge of electronics, and it’s kind of a miracle that I figured out a way to make it work using a grid of wires, diodes, capacitors and a motorcycle battery!

    I did not succeed in selling the idea, but it was fun to work on, and it was nice trying to be a rich and famous inventor! :-)

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