Make Podcast: Weekend Projects – Making A Drawbot


When I saw the scribbler robot article in Make: 07, I had to make one. At first I thought it would be easy to get some steppers and boss them around with some software. Well that’s what needed to be done, but it wasn’t easy. Luckily I got a lot of the hardware issues out of the way by finding a medical robot that organized vials of blood off ebay to convert into my robot.


It came without any controllers so we slapped the Make: Controller on there and since the stepper motors were rated at 1.2 amps and the Make: Controller can only output 1 amp, I bought some Interinar microstepping drivers with very attractive heatsinks.

Then I needed help. I’ve never worked with robots and I could grok the hardware, but the software My friend 3ric held a robot-making get together and we recruited friends to help. Divide, Choong, Melvin, and Brian came onboard to help deal with the software issue. It turns out that it is really hard to get an image to turn into an outline that can get turned into code for the microcontroller to boss around the motors. We’re still working on this problem, right now we can get it to draw a star, but we’ve got a ways to go to get it to drawing faces.

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14 thoughts on “Make Podcast: Weekend Projects – Making A Drawbot

  1. wiml says:

    You know about software like potrace, right? Once it converts an image to a bunch of paths and emits them as, say, SVG, it should be easy enough to translate those into a bunch of stepper movements.

  2. Bre says:

    Potrace is one of the programs on the table at the moment, thanks!

  3. JavaMoose says:

    I came across some software called Photo V-Carve that I was planning to use with my CNC machine. Since yours is a bit different, basically a plotter, the results might be interesting – but worth a try. This software will output GCode, then a GCode -> Step/Dir software (Like Artsoft Mach3) would be used to drive the machine.

    Photo VCarve:

    Artsoft Mach3:

  4. evanfoss says:

    I realize it looks good to have the wires all wrapped like that but it puts unwanted stress on the conductors inside the insulation. I agree it looks nice but it can become a big pain when you have to unwrap all of them to replace one line in the bundle. I have experienced this pain trust me.
    What did you use to convert to line drawing? I have seen it done in octave but that is not exactly easy to interface to something doing this kind of raw i/o.

  5. Robotguy says:

    If you are lookin for an algorithm rather than separate software, try the Hough transform for a start.

  6. bgraham111 says:

    Here is a website with a wealth of resources.
    It’s a bunch of people making their own home made machine tools all computer controlled.

    Also, I’ve seen people put the pen on a spring loaded holder so if the surface you are writing on isn’t totally level, the spring “shocks” will smooth it all out. Should work on a 2.5 axis machine like this.
    Good luck!!

  7. Qode says:

    Oh, thats just too cool.

    I just thought of doing something similar, but using an etch n’ sketch instead of a pen. It would be alot harder because you would have to make the entire drawing a single line, but it would still rock to see something like this being built.

    … then you can drain out the sand and sell the piece on ebay for a kajillion dollars (mwhahaha)

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