K’nex Whiteboard Plotter


[Jerry] has been wanting to put together a whiteboard plotter for some time and just recently got around to building one.

The plotter draws pretty much about anything he can imagine on a white board measuring just shy of 2′ x 3′. The design first started off with a Basic Stamp board at the helm, which he sourced from another project he no longer had any use for. The Stamp worked for awhile, but eventually he ran into problems due to the board’s limited 128 bytes of program space. Needing a more robust micro controller, he switched to an Arduino mid-project, which he says runs the plotter far faster than the Stamp ever did.

The plotter uses a pair of stepper motors mounted on a horizontal platform situated above the whiteboard. Much like this large-format printer we featured earlier this week, the steppers vary the length of a pair of fishing lines, moving the pen precisely across the board.  As you can see in the image above, [Jerry] has been able to create some pretty intricate patterns with his plotter, and we imagine they will only get better with more refinement.

Be sure to check out his site for more details on his build process as well as several additional samples of the plotter’s capabilities.

8 thoughts on “K’nex Whiteboard Plotter

  1. No wonder it runs much faster using an arduino, seeing as the PIC on the Basic stamp needs to parse the Basic code every time it’s run. It’s probably the most stupidly designed microcontroller setup around, Raping that poor PIC every time.

    That said, I love the use of good old knex for this. Knex doesn’t get enough credit for what it’s worth so it’s good seeing a hacker building something nice with it.

    1. The ripples are due to the string winding unevenly sometimes on the sewing machine bobbins that I glued to the stepper motors. Even when they wind evenly the bobbins are not exactly centered. I have done some patterns like close spaced spirals and rectangles that show the effects of both things.

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