Tag Archives: BEAM

Styrofoam Plate Hovercraft: My Debut in Popular Science

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working-prototype-02-with-battery-and-fans-still

Of course I knew for months in advance that this was coming, but what I did not know, until I actually received my copy of the March 2015 print issue, was that I also got a coverline.

2015-02-27-March-2015-PopSci-Coverline

This project actually started as one of six ideas I sent to littleBits when I began negotiating to develop projects for their Explorer Series kits in late 2014. It was inspired by the well-known “Kelvin” hovercraft activity developed for primary-school STEM educators. There was a lengthy prototyping process in which I tried to produce a workable styrofoam-plate hovercraft using littleBits components; when it became clear that the single 5V case fan bundled with their Premium Kit was not going to be able to lift its own weight, I pushed forward anyway, adding fans and stripping away other components as needed until I got to a reliable power-to-weight ratio. The 5V fans that I used in the final build (Sunon #MB50100V2-000U-A99) are exactly the same part used in the littleBits Fan Bit (though they are deliberately overdriven at 9V).

[vimeo https://vimeo.com/106963508 w=600]

Here is some heretofore unpublished video of the finished prototype in action. On a fully-charged 150mAH NiMH 9V, it will float for about 5 minutes. You can see that it tends to precess in the same rotational direction as the fans themselves; I would like someday to try a similar build using counter-rotating fans to cancel the net torque, but it will have to use bare motors rather than all-in-one case fans, because case fans all turn the same direction and are not, to my knowledge, ever available in the opposite handedness.

Hoverplate Exploded Illo 001

If the torques could be made to cancel, the next logical question is whether they could be modulated to provide steering. It seems likely to me that a four-fan configuration using impellers counter-rotating across the centerline and controlled by a “Herbie” type BEAM circuit with two photo-diode sensors could in fact be arranged, fairly easily, to both float the vehicle and steer it towards the brightest light source in the environment using a “net torque” steering mechanism.

MSE-5: The Weekend Project That Wasn’t

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An elaborate but small hand-assembled BEAM style robot with carefullly coordinated colors in blue and white.

All parts are from RadioShack. Photo ca. August, 2012.

This is a Herbie-style BEAM photovore with a reversing relay. But instead of a bump switch, the “retreat” reflex is triggered by a sharp, loud sound like a clap. It was developed for MAKE’s RadioShack “Weekend Projects” campaign in the summer of 2012; the prompt specified a project that responded to both light and sound. “MSE” was intended to nod at “Mousey the Junkbot,” Gareth Branwyn’s famous Herbie-style build from “The Absolute Beginner’s Guide to Building Robots” (and MAKE Vol 06). MSE-5 was by most standards a failure, coming in three weeks past deadline and well over budget due to persistent line noise problems that would cause the reversing relay to trigger over and over again. I did eventually iron out the bugs, but the final build was much too complicated and never saw use. Still, the finished ‘bot turned out pretty sharp-looking, and I learned a heckuva lot about electronics in a very short time.

Though I can’t necessarily recommend that anyone should build it as-written, a complete PDF of the unpublished Make: Projects MSE-5 tutorial is available at the link below.

MSE-5: A Light- and Sound-Sensing Robot

OCD Bristlebot

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A yellow toothbrush head, with white bristles, that's been cut from the handle. The bristles are on the ground, and there's a layer of foam tape on the back of the head securing a small piece of black phenolic board that matches the shape of the head. On top of the phenolic board are a small pager motor, mounted in fuse clips, a toggle switch, and a CR2032 coin cell battery holder with a battery inside it.

Plastic toothbrush head, fuse clips, pager motor, toggle switch, copper-clad board, double-stick tape, coin cell and holder.

I made this little robot sometime in mid-2014. The motor case, fuse clips, and most of the underside copper layer are grounded, with small “islands” manually cut clear to carry Vcc. The sides and top of the phenolic board are stained black with Sharpie marker, and the foam tape provides a solid interface with a bit of give to accommodate the underside solder points. The toothbrush belonged to my grandmother; I found it in a travel kit in a piece of very old luggage.