Pendulum Print Bot

Pendulum Paint Bot



A servo driven pendulum gets a robot swinging attached to an anchor via a cable winch on any canvas. A 2-axis canvas is created which could scale to any size of canvas with the only expense of the cable while only one anchor needs to be attached to the canvas. Indoor (whiteboard) and Outdoor (building walls) use are possible. The robot will carry different sets of tools, options include air brushes (RGB for mixing colours), spray cans, crayons, markers, optical laser for cutting material, etc. Images uploaded to be printed will be compiled depending on the toolset in use.

What do you think? 

Good News Everyone: Typewriter fully functional.

After many hours of work, my typewriter is now fully functional and printing your tweets. Check it out at

At the time of writing this, it actually already printed 68 tweets from all over the world.

However, since this is a project that will probably never be 100% done, here are my upcoming optimization tasks:

  • For whatever reason the USB WiFi dongle on the raspberry pi burnt. Replace to have ultimate mobile experience.
  • Streaming through my phone is not optimal. Best setup would be using a USB webcam driven by the raspberry pi which could stream up to a service that is capable of many viewers (sound / almost realtime)
  • Newlines are now done by me pushing a button, since I need to change the paper and be in power of the roller that brings in the paper for that. This should be optional and make the new lines by itself.
  • Endless paper is needed and attached to the cartridge to actually be fully automated.

Any thoughts on this / hints for streaming, please leave me a comment.


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Typewriter to Printer: Setbacks & Progress

I totally forgot that just having a web video stream of what is happening on the typewriter is not enough. What if actually a few people want to watch it at the same time? Bummer, have to investigate that. So far tests showed not even enough frames come out of that android IP cam app I am using right now to show the actual experience of the typewriter typing by itself. Any ideas for a solution? Please let me know.

Also I fried another one of the tiny motors with gears that make the new lines. I had an extra one and started just printing one letter per row. So since I did not get the cartridge return working, I just disabled the spring that would push the cartridge further and the typewriter would just print on the small cashier paper roll one letter a line. A workaround I am not happy with.

I will need to get some more supplies now to connect all keys and make sure the tweets to @lepetiteprinter will end up in the print queue on the server so the raspberry pi can grab them from there. So from there on we can at least print in a straight line until I have the cartridge return figured out. Any new ideas what to try for that? Actuators that can pull about 20 cm?

Good News

Harvey Moon recently turned a typewriter (also Remington, different model) into a printer for an art installation. Check it out, great work!

Automatic Typewriter from Harvey Moon on Vimeo.

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Typewriter to Printer Conversion, Update (getting close)

Good News Everybody. The typewriter (actually the raspberry pi) is now capable of picking up print jobs from my typewriter API.

See yourself in the following video.

For now I just use a web interface to add the jobs manually but soon the jobs will come in from twitter via a hashtag or tweets towards the typewriter. It’s a Ruby on Rails App hosted on Heroku with a password protected API to make sure only the typewriter himself picks up the new jobs. Also as soon as the typewriter picks up a new job, its status changes. So based on that I can let people know when their job started / is done.

More Good News. All keys are connected now (no numbers though) and are WORKING!!

Just not at the same time yet. Reason for that is that I have been trying to solder up a better control board and failed again on the design. Why I wanted to have a soldered up control board was to make it easily and quickly replaceable (modules). So a 16 pin cable would come from the raspberry pi and plug into the control board while a 32 pin cable feeds the solenoids while another one feeds the new line motor and another one the page return. Besides being able to replace things easy, I thought it would cause less issues if the table is moved since everything is soldered up and no pins can move (compared to a breadboard setup).

That said, I will just use breadboard for now, since I lost too many parts already in soldering up control boards. I guess I am bad at that.

I changed the ribbon, got it at Stables, no problem. Had to roll it over to the typewriters wheels by hand though. What I hear from people that worked with typewriter before (back in the days) I can roll this ribbon back and forth a few times before it will run out. Not just once. That’s good.

Camera to stream the printing process

Although I thought I would use a webcam (USB to raspberry pi) to make things easier (compared to a network camera because of being able to time things from the raspberry pi rather than the web app), I just had the idea to use an HTC smart phone I have sitting around (it’s actually a good phone, I use it whenever I am back in Europe). Sure enough, there are many apps around to turn that, just via WiFi, no SIM card needed, into a good network based camera. So 20 min after the idea, I got it working via “IP Webcam” and now have a stream that is good enough to go on the website to show people their tweets coming out of the typewriter.

Typewriter Beard
Typewriter Beard

Things to figure out from here

  • Cartridge return is still a challenge. I am at a point where I just want to use the backspace and therefore got a very strong solenoid to do the job, but now need another voltage level to make it happen. (Workaround, really)
  • Paper Size, I do like using the small cashiers rolls, since they do not need a lot of cartridge movement to set it back to the start. For tweets that is okay, since I fit about 25 characters on it anyway. If we want to get more serious, there is bigger rolls (for fax machines I have seen so far) but don’t want to worry about it too much right now.
  • Hiding or Showing? There is now a lot of electronics involved. What is nicer, not to see any of them or show them all right away? Right now the typewriter table scares me.

As always, if you have any ideas how to make this project better or have any questions, feel free to comment here or contact me directly.



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Typewriter to Printer: Software Update

I am turning an almost hundred year old typewriter into a Twitter printer.

An update is needed here, since a few things changed, not as much progress as wanted was done though.


I decided for the future of the project to use a Raspberry Pi to operate the typewriter and the connected webcam.


Arduino WiFi Shields are expensive compared to a $10 WiFi USB dongle. Also I can plug in a fairly cheap webcam via USB to the RPi to show images of the actual print job without bothering a network camera. However, I had an RPi around and got the needed python script to read from an API (the typewriter API) and send according signals via a cobbler board going within half an hour.



The RPi runs a python script that does nothing else than grab a string from an API.

So it basically just gets a string, like “print me this please” and will then according to the characters, send the right signals to the shift registers that control the transistors that will trigger the solenoids. Also it makes a cartridge return and new line when needed based on settings, like every 10 characters.


Compared to having the web based print queue push jobs to the typewriter via arduino and probably bother it too much if stuff goes wrong, the RPi python script only asks for jobs if it is okay to do so, but does not have to worry about anything else, other than the paper size.

That also means if I need to reload paper or whatever happens, I just unplug the RPi and fix the typewriter while the online print queue can keep growing.

Also the API will only have jobs in the print queue if the web app decides to put them in there, so it can be from there configureable if hashtags from twitter, or just retweets from one account actually go into the queue.

Therefore there will be an interface to maintain the print queue (auto fill print queue because of name / hashtag, delete tweets, prioritize tweets, easter eggs, etc)

Furthermore, the web based print queue manager can send out tweets/ reminders / emails 5 min before your job is coming into the typewriter so you can watch it happen and after it is done send you the link where to find the screenshot of your print being done.

Considering my last post, I did move on quite a bit: 

  • Tested the shift registers (but new challenge with the raspberry now) need to to it again.
  • Laser cut pieces are wonderful but I got at some point cm and inches mixed up, no biggie, but will do it again some day. The solenoids are not working right now anyway, I switched to fishing string, it has therefore a little play that won’t trigger the key enough to do the trick. I will need to go back to wire when the solenoids are sitting exactly under the keys.
  • Cartridge return I tried a few things now. Some very promising, some just crazy. Undecided what to go for.

Anyway, most of the software got figured out, since I had to step away from the hardware for while to brainstorm again about the hardware.

If you have ideas, let me know. Cheers, michael



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Good News Everyone!

After thorough investigations I believe to have solved the last mechanical challenges to make full control of the typewriter feasible. (in the least invasive / visual way)

  • cartridge return can be done by rolling up a string around the corner and released after it is done OR a motor with gears right behind it and raising the bar for the tabs to connect with the gears there (less hidden)
  •  New Line: stepping motor, gear and belt to be able to sit on the cartridge that slides left and right.
  •  key hammers get stuck: not enough power in the spring that was used to pull them back, can be easily achieved through extra weight on the hook of the spring.

Functional Teeth via Implants

A couple of weeks ago, I decided to get a tooth replaced, by an implant.

My sister and me have this genetic issue, where deciduous teeth (baby teeth) are not replaced by real teeth (I think it is called Hypodontia). Anyway, I just had one and dentists in Austria, during my childhood, told me it will be fine (since it was covered in Amalgam), until I grow up. So two years ago, at 23, I decided, I grew up and should figure this out.

I got the tooth out and started shopping for a good implant that would last (kind of like shopping for a car, asking for warranty and maintenance costs). However, my dentist in Austria told me, he won’t do it, since I am moving to Canada soon and they have “more experience there”.

After looking around a little here and talking to people, I found the dental practice of my choice and just did it.  15 minutes after my appointment started, I was out of there already, with a nice socket in my mouth. If you want to see my mouth right after the surgery, click here.

To cut a long story short, this socket in my mouth got me thinking about a functional tooth:

  • Sensors – Can I put some sensors in the crown that analyze calorie intake or report whatever can be analyzed by breath?
  • Energy –  My Smart Tooth could generate enough energy to run itself and sync with my computer via Bluetooth (funny, eh?) by just chewing, since there is a lot of energy anyway.
Way more research needs to be done on this. Imagine, having a tooth implant anyway, what it could be useful for.

English Idioms learned the hard way.

Photo by Jeffrey Beall

Do you know what “being half in the bag” means? I thought I did, until this happened …

First, if you know what it means, read on. If you don’t know, or just maybe know, read this! English is not my first language, so while living in an English speaking place, I do sometimes reuse phrases and idioms without double-checking them, since, to be honest, it is just not feasible, and works great most of the times.

Well this is how it worked out with “being half in the bag”.

During my first visit in Toronto (years ago) we were invited to a New Years Eve party at a friends place. When we arrived, the host opened the door in his bathrobe and said: “Thanks for coming over, I am already half in the bag so make yourself at home, I will be with you in five“.

Continue reading “English Idioms learned the hard way.”

How a park made a fool out of me, 3 times. True story.

Considering a downtown park, in a mega city like Toronto, I assumed the following things are impossible, can’t exist or just won’t work. Oh boy, was I wrong:

1. Did you know white squirrels exist? No? Me neither, until I saw one at the park!


2. Checking out the neighbourhood of an apartment we where going to see, I discovered this huge park where Google Maps revealed 8 tennis courts in there. Looking forward getting some use out of my racket, I considered worth shipping over from Vienna, I started searching for the Tennis Club operating it, trying to find out membership fees, etc. I did not find anything! Okay, maybe they just don’t have a website. After moving there I walked up the the tennis courts and just asked someone about where to get a membership and how much it is.

Continue reading “How a park made a fool out of me, 3 times. True story.”