An electric typewriter is a rare and wonderful thrift store find, and even better if it still works. Unfortunately, there’s not as much use for these electromechanical beauties, so if you find one, why not follow [Konstantin Schauwecker]’s lead and turn it into a printer?
The portable typewriter [Konstantin] found, a Silver Reed 2200 CR, looks like a model from the early 1980s, just before PCs and word processing software would sound the death knell for typewriters. This machine has short-throw mechanical keys, meaning that a physical press of each key would be needed rather than electrically shorting contacts. Cue the order for 50 low-voltage solenoids, which are arranged in rows using 3D printed holders and aluminum brackets, which serve as heat sinks to keep the coils cool. The solenoids are organized into a matrix with MOSFET drivers for the rows and columns, with snubber diodes to prevent voltage spikes across the coils, of course. A Raspberry Pi takes care of translating an input PDF file into text and sending the right combination of GPIO signals to press each key.
The action of the space bar is a little unreliable, so page formatting can be a bit off, but other than that, the results are pretty good. [Konstantin] even managed to hook the printer up to his typewriter keyboard, which is pretty cool, too.
Printers were way beyond my graduate student budget in 1975 when I got my Altair 8800. I bought a used IBM Selectric and added about 11 or 12 solenoids to make it into a printer (~5 char / second). The selectric is ideal because the text keys are each mechanically binary coded with 6 bits (the shift key made a 7th bit) to rotate and tip the “golf ball” typing element for printing. Only 7 solenoids needed for 96 characters! I added dedicated solenoids for space, backspace, tab, return, strike (and maybe something else, memory is hazy). I used the 8080 and software timing loops to sequence things correctly. I used it to type my PhD thesis and saved almost the cost of the thing. Good old days!
Would have loved to seen that! The wild thing is being based on a typewriter, it probably had way better print the those expensive printers.
The print quality of a Selectric with a polymer ribbon is very good. It would have been better than any dot matrix or line printer.
I did one couple years ago as a “because I can” project
https://hackaday.com/2023/07/25/selectric-typewriter-goes-from-trash-can-to-linux-terminal/
Don Lancaster describes a similar method for TV Typewriter output in his book on them.
There was a standard version available from IBM, as well. I would guess the price back in the day is best described as $$$. We had one available when I was working on 360’s and 370’s. Slow. Very functional. Every user had to purchase their own type ball(s) in the faces they wanted to use. I don’t recall if it was usable as a terminal or only as a spooled channel for printing.
Yes. It was the IBM2741.
I got one when the Grenoble University data center shut down the IBM 360/67 in 1980. It becomes my I/O device for my first home made computer.
Marvelous compared to the KSR 33 I had also.
IIRC: the default type balls were not the same layout as the standard typewriter ones, though they were physically interchangable. EBCDIC to selectric control bars, I would guess. One had to specify which layout was mounted when sending a job. I think APL was an option, too. I probably still have a few in a box somewhere, but I probably won’t remember to look when I get home (I have a couple keyboards from 5252’s and 3278’s from the mid/late 80’s and probably a test fixture for the acoustic wire memory from the 5250 series, as well as a bunch of other things I snagged back in the day. The frame grabber I had– have?– for the PDP8 is rather unique, if I do say. Weird times) The detail fade with decades.
Yes, I had an APL ball for mine. Never put it to practical use ’cause no APL for the 8080 back then, but it was a fun curio.
We had the same setup connected to a SWTPC 6800. I think there was a kit for the typewriter conversion. Before that, the computer had a box underneath with a row of red LEDs and a row of toggle switches for I/O, so the Selectric was a big leap in usability!
Gadgets like these were advertised in homebrew computer magazines in the 70s and early 80s. I never saw one in the flesh (or even in video, like here) though.
back in the day, there was a product you could by called “robotyper”. i still remember the ads in the magazines…
I did a similar thing with a typewriter with electrical keyboard. The keys was connected in a matrix 8×8 so I connected two 8051 in the row and column with the common pins connected together.
Then I redirected the printer routine in my Acorn Atom to my own code. It worked, but it was slow.
Clank-Nova, is that you?
IIRC there was an actual 3d-party keyboard overlay that you could buy for your Selectric and it was as ugly as you might imagine. I don’t know if any were actually sold but if you wanted to spend a month digging through back-issues of Byte it’d likely be there.
I was ripping on the people that built a dedicated ‘word processor’ the other week (dedicated word processors suck Wangs).
My ending burn:
‘What are you going to redo next? Print using an solenoid array sitting on a Selectric?’
Kids think they invented everything.
Supposed Greek idiom:
‘Young boy finds out where babies come from. Gets so excited he runs home to tell his dad all about it.’