Step-a-sketch

[Chris] is getting his feet wet with Computer Numerical Control starting with an Etch-a-Sketch interface. This is a great way to start out because the really tough parts of the project are already inside of the toy. He’s replaced the two white knobs with stepper motors and connected them through a mosfet network to a PIC 16f84a. The PIC then gets its commands from a computer via the parallel port.

A video of the CNC machine can be seen after the break. He needs to add a frame to increase the precision of the images drawn but this first attempt is pretty good. We prefer to have the computer in charge of the design because controlling an Etch-a-Sketch with a mouse doesn’t make our drawings any better.

[Thanks Jeff]

Comments

  1. McSquid says:

    I don’t want to be around when you automate your son’s megazord

  2. Mr Dan says:

    I have often pondered doing something similar, but using the PC to pass in an image which gets converted to line-work and then drawn on the ‘sketch.

    A classic hack :)

  3. 36chambers says:

    I have often thought the same thing, then wondered if I can get the resolution high enough to pass it off as my personal handmade artwork and then make a living as a professional etch a sketch artist…

    You have to at least wonder if these guys are doing it this way, not putting anybody artistic talent down, just saying, its easily done, and I have never seen a timelapse video of one of these etcha sketch artists’ making a piece.

    Sam thing with so called “brick artists” who are just using Ldraw to make building instructions for 3d objects and then after they put it together and everyone is amazed, they act like they made it freehand…

    Im calling cheater on both types.. but hey make a living how ever you can, im definitely jealous.

  4. Paul Potter says:

    Pure brilliance.

  5. adamziegler says:

    It was a similar project like this a few years back that got me interested in making effort to start doing CNC stuff.

  6. MS3FGX says:

    Clever way to get started. Might want to figure out how to hold that thing down though, looks like it was walking away there.

  7. stharvey says:

    what a 1111’n nerd!

  8. therian says:

    it strange choice of Parallel port I mean why not serial port, 16f84 dont require a rs232 converter, just couple k value resistors

  9. Howie says:

    therian, I think it’s more that most of the available CNC software still expects a parallel port (e.g. Mach3).

  10. Agent420 says:

    This is a popular project, and congrats on getting it working, but really there are several better examples of this that have been out there for a while.

    This is also a good time to learn about stepper control – fwiw one of the main things to understand is that they perform much better when they are current controlled (fed from a much higher voltage than what is printed on the case) and it’s also usually easier to use a dedicated controller chip.

    That said, having built a couple of these myself I will also say that the older usa built toys work much better than the cheap chinese crap sold today – there is less play in the mechananism, and many of the newer ones also jump around when the string knots run get caught.

  11. mattbrawn says:

    This is a cool idea and not dissimilar from one of the winning Nokia PUSH N900 entries, Sketch Your World.

    The Sketch Your World team have been running test images from an N900 for a little while and their results have been looking pretty impressive.
    You can check out their progress from here:

    http://blogs.nokia.com/pushn900/

    Or about the PUSH project as a whole over on this Hack-A-Day article: http://hackaday.com/2010/01/05/nokia-push-competition-update/

  12. Stunmonkey says:

    Most of you are young enough to not realize the PC has a specially designed CNC port already. Its called a parallel port.
    To you young ‘uns, a parallel port is just an ancient slow printer port.

    A little secret – it was originally designed as, and still functions as, the PC’s dedicated CNC control port. Still used to this day for that by the professionals, it’s what it was designed for.

    Running data over it was a short-term kludge to use existing ports during a time when PC peripherals rapidly evolved, and was just a bad idea.

    You want to do CNC, go buy a dedicated CNC controller port. It’s called a parallel card and it’s under $10. No Arduino needed.
    It would have solved all of his timing problems on this project with the motors running at the same time, as well as several others.

  13. S says:

    he should have made an ebook reader out of it
    all the damn readers are so unnecessarily complex.. they don’t NEED wifi goddammit!
    but one made of an etch-a-sketch.. that i would love to have
    besides, if it’s secret documents, you can just shake it away

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