BrachioGraph by Daniele Procida

Posted on April 12, 2023 by MakerBlock

BrachioGraph by @evildmp / Daniele Procida

It would be incredibly difficult for me to pick my favorite kind of plotter / drawing robot. I love hanging plotters for their impressive scale and low cost. I love EMSL’s AxiDraw and EggBots for their incredible precision, bulletproof design, fantastic support, and deep community.

But, I’ve got a real soft spot for a microcontroller + 3 servos. Daniele’s BrachioGraph is a self-described “cheapest, simplest possible pen plotter.” Seeing as how there’s little more to this drawing robot other than a Raspberry Pi Zero, three micro servos, a USB cable, a pen, a few bits of wire and … just … stuff? (Some of their pictures include popsicle sticks, clothes pins, binder clips, nail files, and presumably glue or rubber bands. Despite the deceptively simple build of materials, the GitHub has 34 contributors and has continued to be developed over the last 4 years, and as recently as 5 months ago.

In fact, this project has been around so long (since 2019) that a write up on the Raspberry Pi blog describes the microcontroller as being “$5 Raspberry Pi Zero.” Ever since RPi Zero’s became unobtainium, it’s difficult to find them scalped for as little as $25, let alone the current sticker price of $10.

Hanging Wall Plotter by HomoFaciens

Posted on April 12, 2023 by MakerBlock

“V plotter” / Hanging Wall Plotter by Norbert “HomoFaciens” Heinz

I’m very late to the party noticing the stripped down, simplified, and well documented hanging wall plotter by Norbert “HomoFaciens” Heinz posted by Liz Upton back in 2015! Norbert’s blog post provides lots of photos and details, while his videos more information with additional nuance.

One of the things I love about this style of drawing robot is that all the materials and hardware are fairly inexpensive, much of it can be built out of materials people already have or could salvage, almost any part can be over-engineered or streamlined, and the results are almost disproportionately amazing.

Great project Norbert!

Piccolo files and information available!

Posted on October 20, 2014 by MakerBlock

The small robot from Diatom Studios called the Piccolo was the inspiration for my own TinyCNC. The Piccolo was first announced in February of 2012, but Diatom Studios just released a new video of their robot with lots more details. They’ve also released all the source under Creative Commons, so you can track down their source files on Github and follow their excellent building guides to create your own.

New Piccolo video:

Older Piccolo video:

Plotter Profiles

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Mirobot by Ben Pirt

Posted on March 23, 2014 by MakerBlock

Mirobot, ready for drawing!

A few weeks ago I stumbled across the Mirobot website after seeing a post on the Arduino forums. The creator, Ben Pirt, designed this cool open source drawing robot that is driven over WiFi to roll around and draw. One of the nifty things about this project is that the robot is that it has an almost unlimited drawing size.1

Ben was kind enough to answer a few questions about his project:

What is the Mirobot?
- Mirobot is a simple drawing robot that’s designed to help children learn about programming and technology. It’s all open hardware and software so once you’ve done some of the basic exercises and you’ve built up your confidence you can start hacking it to do different things. It’s battery powered and WiFi-enabled which means you can put it on your home network and just start using it from any web enabled device.
How did you get started in robotics?
- This is my first robot really! Although I guess back in the 80’s was when I first got my hands on a robot when I used the BBC Turtle. I was lucky because my Dad was a teacher and was involved int he early days of computers in schools – I was his willing guinea pig. Every school holiday he would bring something home to play around with and the Turtle was always one of the most popular things.
Why did you decide to work on a drawing robot? Where there any other robots that inspired you?
- A couple of years ago I took my kids to the Science Museum in London (worth a visit if you ever get a chance) and saw one of the original Turtles that I’d used in my childhood. After being immersed in technology for a while now it struck me that what was then a very expensive and complex machine could now be constructed relatively easily and at low cost. In the era of the original Turtles you were lucky if you had one per school, but with an open hardware approach and using open platforms like the Arduino, much of the development is already done. I’m now able to build a robot that improves on the original (it has batteries, uses WiFi) at a fraction of the cost.
- But the real reason I decided to start work on the project was so that I could build it with my kids. We built the first release over Christmas and it’s evolved from the learning that gave me.
Who do you see using these robots? What do you hope they’ll learn as they build and program the robot?
- It’s designed with children in mind – it’s been made easy to assemble and I’ve put a lot of time into making sure the PCB is easy to solder. I’m hoping to work with schools so that a class can all build their own robots and then start learning by using them. When you build the robot yourself you have a much greater appreciation of where it came from. As you put together the PCB I take the opportunity to explain what each piece is doing so even if you don’t fully understand how it works, you still get more of an understanding about what it’s doing. You also get more of a mechanical understanding about how things fit together because nothing is hidden and you can see what everything is doing. Once you start using it you can obviously develop your understanding of some basic programming, but once you’ve mastered this there are lots of other ways you can learn by modifying it;
  - – you can customise the web application and learn Javascript / HTML
  - – you can program it from Javascript, either in-browser or via Node.js
  - – you can modify the firmware and add functionality to the robot
  - – you can add sensors to develop what it’s capable of
How big a drawing is the robot capable of? How complex a drawing?
- Well the robot is battery powered and wireless so the question is how big is your piece of paper? I do have some plans to make a massive drawing at some time!
Besides drawing what else could people do with this robot? Do you think there are any commercial or industrial applications?
- I definitely see Mirobot as a base for future experimentation so I can see people adding sensors and making it autonomous. Maybe someone will use it as a base to make the cleaning robots like in the Fifth Element! I’ve intentionally brought out any unused pins on the Arduino to a header so that it’s easy to add hardware.
Why did you choose to go with a custom designed board rather than an Arduino with a motor shield? What other applications do you see for the Mirobot board?
- I originally started with a shield for a regular Arduino but found that it turned out to be quite expensive (and one of the goals of the project is to make it as low cost as possible) and also quite bulky. It began to impact on the physical design of the chassis and was quite difficult to mount (it required screws, and these cost money and add to the complexity of the construction process). I also wanted people to be able to completely build their own robot so liked the idea that you really do build everything. By building a custom board I can make it fit perfectly into the design of the robot.
Why did you choose open source?
- I’m a big believer in the Open Source approach and I think this is the perfect project for it. If the aim of this project is to get it into as many children’s hands as possible then allowing anyone to make it, and also to learn from the making process, is a key part of that.
What’s your favorite thing to draw with the Mirobot?
- At the moment my favourite test pattern is the classic 5 pointed star which can be nicely drawn in LOGO by doing:
  - repeat 5 [
  - forward 100
  - right 144
  - ]
- Although I’m still learning! I’d like to teach it to do some portraits by converting vector images to drawing commands.

Thank you to Ben for taking the time to share more about his project!

Mirobot – drawing!

Plotter Profiles

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As long as the paper, pen, and batteries hold out! [↩]

Doodle Clock by Ekaggrat Singh Kalsi

Posted on March 8, 2014 by MakerBlock

Doodle Clock picture totally swiped from Hack A Day

I found the Doodle Clock featured by Hack A Day in March of 2012 as a result of a comment on that side. It’s not a traditional drawing robot as I feature on this site, but it does have the most important parts – a robot that creates some kind of drawing using a typical drawing instrument.

The setup appears relatively simple – some metal arms, motors, and what I would guess is an Arduino microcontroller of some kind. Although the video doesn’t seem to show the eraser implement, the robot has an almost hilarious method of wiping the drawing surface using the side of the pen holder.1 There isn’t a ton of information out there about this robot – basically just the write up on Hack A Day, the YouTube video, and then a few comments in both forums.2 Fortunately, in the video comment section the creator does provide a brief explanation of the math underpinning this nifty robot:

Use inverse kinematics to find the angles of the motors like the following equations: 
float l1 = 80.4; // the length of the shoulder 
float l2 = 88; // the length of the elbow

double cb2 = 2*l1*l2;

double c2 = (sq(x) + sq(y) - sq(l1) - sq(l2)) / cb2; 
double s2 = sqrt(1-sq(c2)); 
double k1 = (l1 + l2 * c2); 
double k2 = (l2 * s2); 
double base_ang = rtod((atan2(y,x) - atan2(k2,k1))); 
double elbow_ang = rtod(atan2(s2,c2)) + 90;

myservo1.write(base_ang); myservo2.write(elbow_ang);

Many robotic arms use inverse kinematics math to calculate and control position and movement. Although not as complex, the Doodle Clock and Linus use this same math. Now, if you’ve read this far – why not check out this pretty amusing video of the Doodle Clock in action?

Plotter Profiles

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I would guess there’s a small cloth or some thing glued to the side [↩]
Although, I just saw a post on Engadget about it too [↩]

Piccolo by Diatom Studios

Posted on March 8, 2014 by MakerBlock

Piccolo – version 4

The Piccolo by Diatom Studios is a tiny CNC robot – a huge source of inspiration for me. I first heard of the Piccolo in about February of 2012 when they got a lot of blog and press coverage after they launched an excellent introduction video and website. The award winning design 1 features lasercut acrylic parts, three micro servos, and a pen holder. However, since the robot is a 3 axis CNC rather than just a 2 axis CNC with a pen lift, the possibilities for extending, tinkering, and hacking the platform are basically endless.

Although their Piccolo website has been relatively quiet lately,2 there have been several interesting developments. The Diatom Studio crew has posted lots of files, instructions, and code up in their GitHub account, they’ve got a ton of pictures in their Flickr pool that appear to show the design evolution of the Piccolo, and there’s even a LittleBits powered version of their platform.

The latest version shown in their Flickr pool provides a lot of insight into their design process, part choices, and a hit of things to come. The latest Piccolo pictures features an Arduino Pro Micro powered circuit board and three servo connectors upon which the lasercut parts are layered to build up the robot. Unlike prior versions of the robot which appeared to require several different thicknesses of lasercut material, this version seems to require only one thickness of wood, one thickness of acrylic, and one thickness of what appears to be paper. If I were to guess, I would suppose the lasercut paper is used for spacers between the layers to provide clearance for parts to slide through.

This slideshow requires JavaScript.

Lastly, if you haven’t checked out the video, you really need to do that now. I’m pretty confident that you’ll fall in love with this little robot too.

Plotter Profiles

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Scroll to the bottom to see the award links [↩]
Still no launch date – sad face [↩]

PlotClock by Joo

Posted on February 12, 2014 by MakerBlock

Thingiverse citizen Joo has just shared the hands down, cutest robotic drawing dry erase clock you’ve ever seen ever, called the “PlotClock.” This is the kind of awesome robot that makes me want to drop everything I’m doing to build one. Much like the Piccolo video, I could watch this little clock write/erase the time all day. The design is inspired and elegant, using one servo to rock the other two backwards for a pen lift, and using a small “cup” with an fuzzy bottom to transform the pen into an eraser.

Joo has kindly shared lots of photos and instructions on this FabLab wiki and the code on Github.

So…. Does anyone in the SF Bay Area have a laser cutter they could let me use? 🙂

Hat tip and monocle nod to Tbuser for pointing project out to me.

Plotter Profiles

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Linus the Artistic Robot by PixelatedThoughts

Posted on January 30, 2014 by MakerBlock

Linus the Artistic Robot

I’ve always intended that this website be about more than just the few robots that I’ve built. It’s also about other robots that perform art, especially those that draw. I’m hoping to make these kinds of “plotter profiles” a more regular thing on this blog.

Every once in a while I do a search on Kickstarter just for drawing robots. Last week I happened upon Linus – a simple drawing robot which uses open source software. With only a few days to go on the campaign, I reached out to the creator Jacob Balthazor of PixelatedThoughts.com and asked him a few questions.

Why a drawing robot? Were you inspired by any other project in developing your robot?
I guess I was attracted to the poetic irony of a robot; a word we attribute with being mechanical, orderly and blind to creativity, that can create a piece of art in the very human way of dragging a pen across paper. I am working on some software to take this idea further. The program would make Linus randomly grab a picture off of the internet and interpretively draw it daily. This way you would always have a new piece of art every day, freeing Linus from the creative bounds of the users creativity.
Have you used it for anything else other than drawing? What else could you do with this robot?
Because of Linus’s simplicity it can be very easy to modify and and even swapping the utensils he hold can lead to vastly different functions. I am very excited about the possibility of using the circuit scribe pens (a pen that can essentially draw a wire) with Linus to draw intricate circuit patterns on paper. I am interested to see what other applications people come up with for Linus.
What was the hardest part about designing this robot? Why did you choose to go with a inverse kinematics instead of an XY gantry?
The most difficult part of creating Linus was solving the inverse kinematics (difficult non linear geometry problem) math problems to translate the x and y locations that the drawing programs uses to the angles that the robots arm would take to go to those locations on the paper. Tthe mathematical solutions are something that even take a computer a bit of time to compute which is difficult when the robot needs the equations computed fifty times per second. Most other robots are not constructed with arms for this very reason and have mechanisms that move them directly in x and y directions without the need of an equation doing space transformation between. But it was the use of an arm in Linus which allowed us to keep the cost of parts down. Linus would have been less reliable and significantly more expensive if we constructed it with an XY gantry.
Why servos instead of steppers?
Servos offered a more complete and compact solution. If steppers were used instead, a couple things would have happened with the design. First Linus would have grown in weight and size messing with the small form factor. The weight of the steeper on the suspend second joint could potential cause problems. Because steeper motors without gearing don’t have quite the resolution as servos, a gear system would be needed adding quite a bit of complexity, increasing the price and number of things to fail. The servos allowed for great resolution, and ultimately kept the design elegant and less expensive to produce.
What is the drawing area?
The drawing area of Linus is currently 4.5 inches square. But we are working on a way to expand the drawing area potentially to six by six through messing with the inverse kinematics equations and software.

Thanks Jacob! Good luck with your Kickstarter campaign!

Plotter Profiles

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Maker Artist Ytai Ben-Tsvi and his IOIO Board Plotter

Posted on November 5, 2013 by MakerBlock

Ytai showing off his plotter art at Codame 2013

Easily one of the most memorable aspects of exhibiting at this year’s Maker Faire Bay Area was getting to meet and interact with lots of other Makers. Ytai Ben-Tsvi had built and brought a pen plotter of his own design – and it was amazing.

Ytai’s pen plotter used an Android tablet, his IOIO OTG board1 , two stepper motors, two comically large spools, and lots of custom code to turn pictures taken with the tablet into instant portraits on the fly.

His plotter was everything a Maker Faire exhibit should be – highlighting the intersection of art and technology while inviting the audience to be a part of the action. Can you believe this guy was reluctant to call himself an artist?

After Ytai was invited to participate in the Codame 2013 art-tech festival2 he decided to create an entirely new drawing algorithm to turn images into a single line drawing which appears to be sharp scribbles up close and a detailed image from a few meters away.

Photo transformations with Ytai’s ScribblerDemo

What I love about Ytai’s drawing process is that it produces a drawing with a sense of whimsy and movement without the hard number crunching necessitated by a Traveling Salesman Problem3 style drawing.4 By allowing the algorithm to have lines cross over one another, something the TSP method eschews with its own aesthetic, Ytai’s drawings essentially gets “for free” extra dark patches where lines closely intersect.5

Looking at this drawing, it seems to me that an SVG created from his algorithm conveys so much more meaning with far less points than a TSP file. At least for my own PlotterBot, far fewer points would also mean a much faster, and more satisfying to watch, drawing. I would estimate that in the time it took Ytai to cover a wall, I might have been able to create one, perhaps one and a half, drawings. And, as any good Maker does, Ytai has shared the fruits of his hard work in the form of the source code on Github.

Plotter Profiles

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Ytai’s succinct description of the IOIO board says it all, “The IOIO-OTG is a printed circuit board for electronics hobbyists and prototypers, which addresses a very common problem: how do I use my {computer, tablet, phone} to control my {robot, dish-washer, cat-feeder, etc.}.” [↩]
An art-tech festival?! Why the hell aren’t there more of these things?! [↩]
Link to blog post showing a method [↩]
Doesn’t exactly hurt to have a cute kid as a subject either [↩]
Having played with TSP drawings a lot, I have discovered that finding the right balance between lightness versus darkness and simplicity versus complexity and quick versus glacial to be… maddening. Like H.P. Lovecraft maddening [↩]

PlotterBot

Learn how to build a drawing robot

Category Archives: Plotter Profile

BrachioGraph by Daniele Procida

Hanging Wall Plotter by HomoFaciens

Piccolo files and information available!

Mirobot by Ben Pirt

Doodle Clock by Ekaggrat Singh Kalsi

Piccolo by Diatom Studios

PlotClock by Joo

Linus the Artistic Robot by PixelatedThoughts

Maker Artist Ytai Ben-Tsvi and his IOIO Board Plotter