Chumby Controlled Mechanum Wheel Robot

[Madox] gutted an Insignia Infocast to use with this robot. Insignia is Best Buy’s house brand and they partnered with Chumby to make their Infocast line. If you can find a used or clearance model it’s a great way to get yourself and embedded Linux board for a project like this one.

The body and wheels are 3D printed, with design files available at [Madox’s] Thingiverse page. The mechanum wheels work amazingly well, using seven bearings each for smooth operation. The body itself includes a holder for two groups of batteries. One of those battery packs powers the Chumby board while the other is used to power the four servo motors responsible for locomotion. To simplify the electronics [Madox] chose to use a USB servo drive which only set him back about $20.

We’re not sure what the USB dongle on top of the robot is used for. We’d guess it’s a WiFi adapter, since the machine sets up its own access point to act as a controller. But we thought Chumby boards had WiFi built-in. At any rate, check out the video after the break where you can see an Android phone driving the little bugger. There’s a flaw in the code that prevents side-to-side movement, it gets fixed after a video break at about 2:15 and everything is peachy after that.


20 thoughts on “Chumby Controlled Mechanum Wheel Robot

  1. Wow, nice little build. I especially like the innovative wheels used to allow strafing. How well does it work on things like carpet?
    Oh and of course, the required “FIRST!”
    Thanks for all the cool posts hackaday, hopefully I’ll be getting an arduino soon :)

  2. This is going to sound just nitpicking but I try to make a relevant point…

    Robots and RC stuff should be differentiated because ..umm.. they’re two different things. It’s not useful at all to find 100s’ of RC vehicles if you’re building an AI of some level for your robot and try to find similar projects. Also, cool RC builds might take unjustified negativity from being “just a dumb robot”.

    I’m not commenting this because of Madox. What he has built is neat IMO but not once does he say that it’s a robot, anywhere. His build may well become one and that’s what I was expecting in the first place: Chumby+robot does sound promising.

    From wikipedia:
    “A robot is a mechanical intelligent agent which can perform tasks on its own, or with guidance.”
    “..common characteristic is that, by its appearance or movements, a robot often conveys a sense that it has intent or agency of its own.”

    1. I blame ‘Robot’ Wars. Really pisses me off actually.
      However, in this case it may be that the guy’s just at an early stage of development. Let’s hope so, there should certainly be enough processing power left over to sort out some sort of autonomy.

    2. I know over at letsmakerobots there are a couple members working with a chumby and a software package called MRL aka My Robot Lab built by one of the members. The software as I understand it offers a very generic set of building blocks from which one can accomplish many things.

    3. Re: recoding for strafing.
      I wonder if the code wasn’t written for mecanum wheels in diamond format rather than the X that Madox used. By diamond and X I mean if you draw an imaginary line through the angle of the rollers, Madox’s setup will roughly form an X while I have seen some, like the fork trucks(fork lift), form a diamond shape based on imaginary lines through the angled rollers.
      I guess what I am trying to get at is, would a simple swapping of the wheels have fixed the problem as easily as recoding did?

      1. This was a second unit I built for someone else… I think I made a mistake when documenting the original code that I fitted the wheels wrong, then it became a case of ‘was the code wrong?’ or ‘was the documentation(comments) wrong?’

        I have posted but I’ve since put a webcam on now based on someone else’s improvement :)

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