USB Typewriter

USB Typewriter
**KITS AVAILABLE AT USBTYPEWRITER.ETSY.COM**

Why make a USB Typewriter?

There is something very magical about typing on those old-school manual typewriters. The weighty feel of the springloaded keys, the motor-car styling, and the beautiful marks they print on the page all make for a rich writing experience that can make writer's block melt away. However, the mighty hammering of typewriter keys has long since faded away, replaced by the dull click of the computer keyboard.

In this instructable, I'll help you bring your old typewriter back to life by converting it into a USB compatible input device for your PC or Mac! The hack is intended as a full keyboard replacement, so you can get rid of that piece of disposable plastic you call a keyboard and use the desk space for a classic, functional work of art -- A USB Typewriter!

What is so special about this idea?
Others have attempted this hack before, but while those implementations involved endless jumbles of wires, a disemboweled keyboard circuit, and a phalanx of momentary switches, this project involves none of those things and is actually quite simple and easy to implement. Not only that, but it will work on almost any manual typewriter. I have made quite a few of these USB Typewriters so far, which I sell on my etsy, and each one took 5-10 hours.

You can make one too!
Read on, and you will see that this modification is surprisingly easy to implement -- It shouldn't take longer than a weekend to do, and is within reach of an electronics novice. I have made PCBs and kits for this project, which are available in my etsy store . If you are not a wiz with electronics, I would suggest you get the full kit to make the assembly easier. (However, if you are adventurous, it is entirely possible to wire up the circuitry shown in this instructable yourself, using perf-board -- Just look at the schematics in step 3. )

A quick shout out:
This project was created at Hive76, a rad maker co-op in Philadelphia PA. Visit them at www.hive76.org.





 
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Step 1Overview (How it Works)

Overview (How it Works)
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**NOTE: PCBs and Kits for this project are available here**

This project is a lot easier than you might think. Read on.

The Big Picture:

Under the hood of every typewriter (at least, every typewriter I've seen) is a springloaded crossbar that runs underneath all the keys (see picture below). When a key is struck, part of that key pushes on the crossbar, and this causes the carriage to advance, the ink roll to move, and so on. We are going to repurpose this crossbar as a place to mount an array of metal contacts, which are attached to a long, narrow circuit board.  This Sensor Board is wired up to the Interface Board, an Arduino clone that talks to the computer over USB.

Take the time now to identify where the crossbar is on your typewriter -- just look for a bar that swings up and down when you press a key.

The Details:
The USB Typewriter consists of three main components: the Sensor Board, the USB Interface Board, and the Reed Switches.
  • The Sensor Board is a long strip of flexible metal contacts which clip easily underneath the keys of the typewriter. A number of shift registers allows the microcontroller to poll each of these contacts one at a time, each time checking if a particular contact is touching a key. This way, all 40 keys can be sensed with just 4 wires (a serial input, a clock, power, and ground). See the animation below for an illustration of how this works.
  • The USB Interface Board features an Atmega168P microcontroller chip (ie an Arduino chip), a USB Type B socket, and some supporting components (power supply, crystal oscillator, and USB voltage conversion). It controls the operation of the Sensor Board, and sends keystrokes to the host computer over USB.
  • The Reed Switches: Because the Sensor Board only detects keys that strike the crossbar, several important keys go undetected. These include Shift, Space, and Return. To deal with those keys, we use tiny switches that close when in the presence of a magnet. Generally, I find that it is enough to install reed switch next to the shift key, the spacebar, and on the return carriage lever (to sense a "return" or "enter" command), although up to 8 reed switches can be placed near various keys in this way.  All reed switches run to inputs of the Arduino.
  • The Wires: Contrary to what you might expect, the USB Typewriter does not require much wiring.   The great thing about this method is that the typewriter chassis itself is used to transmit signals from the keys.  That means individual wires do not need to be run out to each key -- just a single wire that runs out to the chassis, and 4 wires that run to the Sensor Board.  This makes the USB Typewriter mod very easy to install, and hard to break.
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69 comments
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Aug 31, 2010. 3:14 PMrandofo says:
Very cool. I like how you made yours. It is a lot cleaner than the one I made with a billion wires.
Sep 2, 2010. 9:13 AMImagoX says:
I'm a writer and I **LOVE** the idea of this - I've often windered if there were a way to retrofit my old typewriters tfor use with a PC. However, I'm unclear about how keys like "Alt" and "Ctrl" work - they're not present on a typewriter, are they? You mention them as being "hard wired" in one of the steps, but I'm not sure how this actually works in practice. Also, I assume this hack will allow for "Shift+key" commands for caps, differing punctuation, etc.? Also, I'm also assuming that (since they're not at all present) that there's no way to assign "F" keys via some sort of key combination in the calibration stage? Of course, it's not at all hard to just have a second, actual keyboard plugged into a second USB port for the times you need an "F" key. Last, I'm pretty sure they do, but when the typewriter is manipulated, the keys still articulate and strike the drum, the carriage still lifts and slides to the right, etc. yes? Thanks!
Sep 2, 2010. 9:55 AMImagoX says:
So if they're on the circuit board, how are they manipulated? Can one use a momentary switch, perhaps, attached to the typewriter chassis? How have you historically accomplished this, or have you just not bothered? Thanks!
Dec 4, 2011. 7:02 AMLed Man says:
Hey man that is really cool, i have an old Type Wrighter some were in my attic im thinking about doing this thanks man
Nov 9, 2011. 5:30 PMUkzs0206 says:
Um, they are manipulated by pressing the buttons. I usually mount the Touch Screen Stylus
on the side of the device, so the buttons can be reached with the left hand while typing. You could of course mount your own buttons somewhere. Every typewriter is different -- that's why its a fun project!
Nov 6, 2011. 3:42 PMtylercard says:
Christmas listed!
Nov 6, 2011. 2:52 PMtheREALcybercat says:
Wow, this is awsome, very clean!
Jul 26, 2011. 4:41 PMCharlieFrancis says:
wow that is awesome! It looks nice and clean, my uncle and I tried to make one, but it was very messy :/
May 22, 2011. 1:02 PMtinker234 says:
wow this is just amazing if i used a frontal surface mirror i coulld make a cool liltle decoreten
Mar 28, 2011. 7:07 PMjlu2 says:
so nice I do like to do try it
but the mini pc is how much?
http://www.topusbdrive.com/custom-usb-c-1.html
Dec 11, 2010. 2:35 PMChunkylover53 says:
is there a way to turn it into a printer for the writing projects on your computer?
Nov 3, 2010. 6:49 PMAntiEgo says:
Clever idea, but i don't understand why you don't make them out of wire... what is it about resistors that works best?
Oct 27, 2010. 4:21 PMMadVegetarian says:
This is really slick!
Sep 29, 2010. 6:12 PMSHIFT! says:
Hey, didn't get to comment this before but awesome instructable! I love typewriters and computers so this is a perfect WIN-WIN combination!
Sep 2, 2010. 4:24 PMservant74 says:
Amost as cool as the using a Selectric typewriter as a printer a friend did in the 1975-76 time frame. Wirt Atmar of AI Cybernetic Systems in Las Cruses NM did the hack and drove all the solenoids that punched the keys on the selectric with his Altair 8800 (Or was it an IMSAI ... my minds details goes after a while :) ... But his was an output device and this is a neat input device! .. I wish I had a picture of his old hack to share with you.
Sep 13, 2010. 3:20 PMDr. dB says:
Whew! An ambitious project for your friend to tackle back in the mid-70's... Of course, by then, IBM had long since made a basic, hard-copy-only computer terminal from their own Selectric line, the "2741", to replace the almost-universal (but deathly-slow) "Teletype ASR-33". The 2741, with a few variants, was still geting some use right on through the early 80's!

The "personal computer revolution" must be credited to both Altair, who "made the ball", so to speak, with their "8800", and IMSAI, who "got it rolling" with their "8080". As far as I know, both used the same INTEL "8080" processor, virtually the only "micro" in existence at the time. By adopting as "standard" many of the features of the Altair while improving significantly on their design, IMSAI helped create much of the market they both then, brielfy, supplied. (Altair's only real "advantage" was Bill Gates' BASIC, quite possibly one of the last pieces of software Bill can LEGITIMATELY claim to have WRITTEN HIMSELF...)
Sep 2, 2010. 10:19 PMlloydrmc says:
In 1976/77 (the heyday of the Altair/IMSAI) there was no such thing as a typewriter an with RS232 port, per se. The closest thing was a teletype.
Sep 2, 2010. 5:12 PMtwighahn says:
thats a neat idea
Sep 7, 2010. 11:09 AMawdark says:
I wonder if anyone has tried to sniff or emulate the iPad keyboard protocol yet. It would be nice if we could get the Arduino chip to connect directly to the ipad and skip the camera connector.

Of course the result will be less flexible but the USB connector is an expensive accessory.
Sep 8, 2010. 12:34 PMjeff-o says:
Maybe you could hack something like this.
Sep 8, 2010. 2:17 PMawdark says:
Yeah, it would probably be easier to take a part and try to either duplicate or just mod. But at $40 it really pushes the threshold of just buying a cheap BT keyboard to work with.

Ebay/sparkfun doesn't seem to have bluetooth breakout boards with HID support wonder why =\
Sep 8, 2010. 2:27 PMjeff-o says:
True, that price is a little high just to hack apart, isn't it?
Sep 5, 2010. 12:07 PMequiliberator says:
I have zero soldering experience save for some ill-fated stained glass projects in high school. However, I've been tinkering around with soft circuitry lately, and in so doing learned of the existence of conductive epoxy. I haven't used any yet myself. Is there any reason I could not use conductive epoxy in place of solder in this project?
Sep 5, 2010. 12:06 PMzack247 says:
cool. too bad i got rid of my old typewriter...
Sep 4, 2010. 2:06 PMchaydgb says:
Great 'ible. I'm going typewriter hunting tomorrow for sure!
Sep 3, 2010. 6:27 AMcherub66696 says:
what is 'C3'?? thanks
Sep 3, 2010. 7:09 AMcherub66696 says:
Cool thanks for fast reply, just orderd all the parts, can get everything form the list at mouser.com for under £10. Thank you for great instructable Chris paton
Sep 3, 2010. 12:04 AMmrsayao says:
Is the backspace key mapped as well?
Sep 3, 2010. 12:54 AMedwatkins says:
That's very cool. I love simple solutions to complex tasks, using the cross bar and key registers was a fantastic idea. It also solves the issue of writers who like using typewriters but are required to submit book drafts as digital documents. Stick in a sheet of paper and away you go! I wonder if there is a way of sensing how far the carriage has been moved when making corrections on paper. Awesome instructable.
Sep 2, 2010. 10:53 AMmfeldman says:
That's great! Now if you could work out USB control to actuate the typewriter keys from the PC you'll have a "poor-man's" teletype. Much like the old style KSR-33 from years gone by.
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Author:jackzylkin(USB Typewriter)