Hooray robots!

A number of people have asked me about building the robot sketched in yesterday’s strip. You’re definitely welcome to, and I’d love to see the results.

There are a couple engineering details that might trip you up. Rotating the webcam is one of them — I don’t make this explicit, but the idea in the blueprint was that there would be a servo inside the robot rotating the retaining magnets, which could be powered off the main battery. In practice, it might be better to put the servo on the outside and power it off the webcam battery — or, if you can find one cheap, simply use an omnidirectional camera.

The reason this is necessary is that I don’t think the internal robot, which is holding the webcam, will spin easily on hard surfaces. This is also the reason the robot uses Mechanum wheels instead of a simpler and cheaper design with a powered wheel on each side and castors or bearings on the front and back. If anyone has any ideas for making the robot spin more easily, I’d love to see them. Or perhaps you can try building the simpler design and see how quickly and reliably it can turn. If it works, it eliminates about half the cost of the project.

If anyone sends in any interesting material on this, I’ll be happy to put it up on a wiki somewhere so other people can tweak the design and develop a how-to. As far as I know, no one has built a robot quite like the one in the comic, so it’d be a great project.

Possible additional feature: cover the robot with little flaps or ridges, add some tweaks to protect the camera, and it becomes amphibious.

Edit: I’ve covered a few additional questions, including why the camera isn’t inside the ball, in this comment.

260 replies on “Hooray robots!”

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  3. Seems I wasn’t the first one to come up with the hovercraft camera attachment idea.

    But I got more:

    Also make the bot inside the ball hover; now we can just have 2 motors to roll around (either a single steerable wheel in the center, or two independent wheels side by side) without the need for complicated wheels. It might also help with dissipating the heat better (the air circulation makes it so more of the heat will reach the ball that is in contact with the outside).

    And to make the camera picture more stable, don’t keep it attached rigidly to the hovercraft cap, put it on a balloon! (attached by strings and/or power and data wires to the cap)

    To have higher control of the balloon (to position and angle the camera, perhaps even letting the bot “emote” with head motions) you could use a set of strings on electronically controlled reels in a Stewart Platform arrangement to hold the balloon that holds the camera.

    And since helium leaks over time, what if you used Peltier modules to condense water from air, then with electrolysis extract hydrogen for the balloon, and also use the heat of the Peltier modules to make it a hot hydrogen balloon for extra lift? Just keep the batteries charged and the bot in a relatively humid environment and you’ll never run out of lift!

    You might be worried that it could become a hindenbot. Well, sometimes science requires sacrifices. Remember to not paint it with thermite though.


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