Practice Makes Perfect For This Ball And Socket Robot

many revisions of the ball and socket robot

Ball and socket joints are useful, but making a part slide over the surface of a sphere, held by magnets, requires a lot of fiddling to get right. We admire persistence and nailing all the details. [Matthew Finlay] has been doing just that with his ball and socket robot. He’s on version six, a testament to his desire to do the idea justice. Luckily for us, he’s documented each version as he went.

Version one, made from a DIY Christmas ornament ball, had no stability around the radial axis, and oscillated badly. Version two demonstrated the problem of centering the mechanism in the ball. Version 3 fixed this problem (it’s covered in the same video). Then version four fixed many of the assembly issues and replaced the servo controllers with an Arduino, but the ‘arm’ piece was too small and mechanically iffy.

Version five used a fabricated bearing. Matthew used airsoft rounds as the balls. Not a good idea. And assembly was a nightmare. So all this progress up to version six shows his improving technique.  Artists say ‘work on your process, not on your pieces’. He’s become much more analytic about what’s needed. He’s started measuring the strength of the robot, and handled issues like adding limit switches so it doesn’t crash at the limits of travel.

Fun build, reminds us of [Stephen Dufresne]’s BB-8.

3 thoughts on “Practice Makes Perfect For This Ball And Socket Robot

  1. This looks like a great project.

    I’ve been thinking of a project that could use something like this once it’s strong enough – an automatic pulses watering system. Think of something stationary on the ground that shoots pulses of water in the air, each one carefully aimed to land on a surrounding plant. The machine could vary the pulses depending on the plant’s needs and could run the pattern many times a day.

      1. You planted bamboo?
        Already fucked…did you plant kudzu and blackberries too?

        Getting a laminar flow tip to work isn’t trivial.
        Made a Squirt mortar one summer.
        Two big guys deadlifting on cables, one guy aiming. About 10 liters/shot.
        To hit the cops on shore, who like to stare at the party and scowl. Got a good 20 meters of laminar, was a big fat (1/2 inch) stream. Lacked range, also they saw and backed away.
        Key is glass smooth inside taper and perfect square even end. I used bondo and car paint tech, it was bitch on ID.

        On hindsight, getting their uniforms wet wouldn’t have turned out well. That was the only thing keeping them on shore. We were set to run like french men. Boats ready. They would have gotten at least one keg.

        On point, ‘inkjet’ irrigation. Use high voltage to aim. Like TV yoke/early inkjets did. / badidea

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.