Why do DrawBots draw on walls?

A wall crawler - on the floor

A wall crawler – on the floor

A commenter named Ellison left a deceptively simple question on my first post in this DrawBot series.1

Ellison:  Why do it on a wall? Why not a drawing robot that draws on a large piece of paper on the ground? I think you’ll get better results from that.

I think there are a lot of good reasons reasons – some aesthetic, some technical, some practical – for having a DrawBot that draws on walls (or other vertical surfaces).

Aesthetically, I really like having a DrawBot that draws on vertical surfaces.  When placed in the room or an adjoining room, I can watch it scritch-scratching away at an enormous drawing.  In much the same way a snail’s meandering trail can be captivating, a DrawBot working out a TSP single-line-art drawing turns an apparently meaningless series of turns into a mass of scrawls that resolve into a work of art as soon as you take a step back. 2

Technically, the DrawBot is an exceedingly simple device.  You could build it out of little more than Arduino, a motorshield, two motors, string, a pen, and whatever you might have lying around.  Much of these pieces you could probably even scavenge for or salvage from other things.  In fact, only the Arduino and motorshield are things you wouldn’t be able to dumpster dive for.  The device works by moving the two motors in concert, such that by varying the length of string reeled in or out by a given motor is used to move the pen in an XY plane.  The one “ingredient” not listed in the preceding sentences is, of course, gravity.  If the point where the two strings meet at the pen did not hang essentially straight down, pulled constantly by gravity, the pen could go just about anywhere.  If you were to place a normally vertical standing DrawBot flat on the ground, the pen would no longer be pulled away from the two motors – and would just flop onto the drawing surface.  Now, you could add two more motors and more string and build a gondola that holds the pen vertically on a flat DrawBot surface while writing a lot more code…  However, I am doubtful you would get any more precision out of such a setup.  And, if you really require precision – an XY plotter might be more to your liking.  An XY plotter build would require lots of hardware (belts and metal rods or metal extrusions), more tools, and be big and heavy, and limited in the size of its drawing capabilities.  It would also be capable of really amazing speeds.  That’s a lot of extra materials, work, custom coding, and loss of drawing capacity for a dubious trade off in

As a matter of practicality, the simplicity of design and materials means this is an extremely cheap project.  An Arduino is only going to set you back about $30 and clones are as cheap as $15.  I picked up two of Adafruit’s motor shields on sale for $12 each, but they’re normally $20.  Screws and/or bolts, beaded cord or wire or fishing line, a big piece of wood or mounting things directly to a wall, 3D printed spools or just leftover spools from thread, a 3D printed gondola or a lasercut gondola or even a big red binder clip.3  Seriously, if you’ve got about $35 and some free time, you’re basically half way to building an awesome fun robot that can make arbitrarily large drawings.  If you’re willing to buy all the materials, it probably won’t cost you more than $150.

I’ll say it again – a Polargraph DrawBot is a quick, cheap, easy, entertaining, and useful robotics project – especially for beginners.  Outside of my 3D printers, this was easily the most rewarding DIY project I’ve ever attempted.  The results are astoundingly disproportionately awesome to the amount of time, energy, skill, and money used to achieve them.

Seriously, what are you waiting for?!  Go order a Polargraph kit from Sandy Noble45 or source the parts from Adafruit6 .7  Or, if you’re going to scavenge and/or source some parts, check out my Polargraph DrawBot parts/shopping lists.

Posts in the DrawBot Adventure Series
  1. Wanna make a DrawBot?
  2. DrawBot, the Adventure Begins
  3. DrawBots for the slow learner
  4. DrawBot - Parts Ordered!!!
  5. DrawBot - The Breakdown
  6. DrawBot - Parts Shipped!!!
  7. DrawBot - What would you draw?
  8. DrawBot - The Hacks
  9. DrawBot - Giant Unicorn?
  10. DrawBot - The Delivery?
  11. DrawBot - The Delivery, Part II
  12. DrawBot – The Delivery, Part III
  13. DrawBot – The Assembly, Part I
  14. DrawBot – The Software, Part I (and an existential conversation)
  15. DrawBot – The Delivery, Part IV
  16. DrawBot – The Assembly, Part II
  17. DrawBot – The Assembly, Part III
  18. DrawBot – The Assembly, Part IV
  19. DrawBot – The Face Palm
  20. DrawBot – The Delivery, Part V
  21. DrawBot – The Silver Lining of Failure
  22. DrawBot – The Delivery, Part VI
  23. DrawBot – The Assembly, Part V
  24. DrawBot – The Assembly, Part VI
  25. DrawBot – Printed Parts
  26. DrawBot – The Assembly, Part VII
  27. DrawBot – The Operation, Part I
  28. DrawBot – The Breakdown, Part II
  29. DrawBot – Printing!
  30. DrawBot – Printing, Part II
  31. DrawBot – Calibration
  32. DrawBot – Pen Selection
  33. DrawBot – How to Recover from a Stalled Print!
  34. DrawBot – Drawing Success(ish)!!!
  35. DrawBot – Pen Selection, Part II
  36. DrawBot – Onwards and Upwards!
  37. DrawBot – Another Successful(ish) Drawing!, and an Update
  38. Restarting a Stalled DrawBot Drawing
  39. TSP FTW!
  40. Speedier DrawBot Drawings
  41. Two new DrawBot links! And an update!
  42. Excellent DrawBot Slides
  43. Another Drawing Robot!!!
  44. DrawBot Practice Tip: A Watched Pot
  45. The biggest inkjet printer ever
  46. Why do DrawBots draw on walls?
  47. Maze Code + Polargraph?
  48. All New Polargraph on the way!!!
  49. Ideas for improving my DrawBot
  50. DrawBot Aesthetic Re-Design Ideas
  51. The Eagle Has Landed
  52. Every Body Needs a Skull
  53. This project is not going to overengineer itself
  54. Overengineered Spools
  55. Overengineered Stepper Motor Mounts, Filament Guides
  56. Overengineered Bolt Endcaps, Case Holder
  57. Sourcing DrawBot Parts
  58. DrawBot - A Tour!
  59. DrawBot - A Preview
  60. Arduino Powered Drawing Robot Poll
  61. Building an Arduino Drawing Robot - On The Cheap
  62. DrawBot - Printed Parts Tour
  63. Unidentified Foam Object
  64. Arduino Powered Drawing Robot - Take 2 (Or 3)
  65. DrawBot, now ACTUALLY wall mounted!
  66. Drawing Robot Pen Holders, Calligraphy Pens, and Thought Experiments
  67. Ideal Qualities in a Drawing Robot Pen Holder
  68. Enough talk! Finally a pen holder!
  69. DrawBot Pen Holder Post Mortem
  70. To Maker Faire!!!
  71. Skipping! How could I forget the skipping?!
  72. Drawing Robot Penmanship
  73. PlotterBot at Maker Faire Bay Area 2013!
  74. PlotterBot.com - a new site dedicated to drawing robots
  1. Photo courtesy of The Kozy Shack []
  2. And, I wonder – if you could map all snails in the world at the same time, could they be working in concert on an enormous message?  Perhaps something along the lines of “So long, and thanks for all the fish”? []
  3. I just love that Polargraph video by Sandy Noble.  To see binder clip in action, skip ahead to 0:27. []
  4. Whose open source work I use for my own DrawBot []
  5. The next time he’s in stock, you better pull the trigger – he runs out of stock SUPER fast []
  6. Where I bought most of my parts! []
  7. And, why not tell them I sent you too? []

2 Responses to “Why do DrawBots draw on walls?”

  1. =ml= says:

    Just getting into Polargraphs (have one on order from Sandy). Thanks for all the posts on your explorations.

    Have you seen EMSL’s StippleGen? It makes creating TSP and stipple drawings a pleasure:




  2. MakerBlock says:

    @TeamTeamUSA: I’m such a slow adopter… I took me a while to really pick up the whole TSP thing. I probably didn’t dive into it until a year after I already had my MakerBot Unicorn working. Once I did figure out TSP (thanks to EMSL!) I went crazy ripping designs out. I’ve only glanced at StippleGen (which would work really well with the EggBot I built but never fired up).
    You know, I’m planning to order a Polargraph electronics kit from Sandy too. I like my setup, but with a solid stand-alone drawing setup, I could really take the drawings to the next level. I hope you share some of your pictures!