How to Spot a Psychopath

I-Wei Huang of Crabfu has a link from his SteamWorks page to his non-steam-powered remote-controlled contraptions. That link is called "Steamless Crap".

He's now given that section of the site a more dignified name, Crabfu MotionWorks. In which the latest creation is...

...the R/C Tortoise.

(Once again, the cat is unmoved. If something in the Crabfu back yard doesn't blow hot steam and shriek like a banshee, it's not worth worrying about.)

Like its ancestors the Swashbots, the Tortoise is a creature that converts movement of normal R/C servos more or less directly into leg movements. It's operated as an animatronic puppet, with no automation beyond servo mixing on the controller.

But the Tortoise is a quadruped rather than a triped - with legs that look as if they're made from the same low-temperature polycaprolactone thermoplastic as Swashbot 3's disturbingly organic parts - and so it can walk much better.

The Tortoise still turns with a Swashbot-esque wiggle, but when it's going forward or backward it's much more efficient. And it's all based on only three servos - each pair of legs is one arch-shaped piece of plastic. (There are actually four servos in the Tortoise, but one just moves the head.)

The Tortoise's clumsy high-stepping gait makes it look, to me, like a creature that's going to be very very large when it grows up.

(Via.)

When I-Wei "Crabfu" Huang created his third Swashbot last month (previously), I never got around to mentioning it here.

Duly rectified:

The grouper mouth and skull-like carapace make it look kind of malevolent... until it starts moving. It still kind of looks as if it's positioning itself to jump onto your face, though.

The "Shapelock" plastic from which Swash3's made is to regular plastic as Wood's Metal is to normal casting alloys. The plastic's chemical name is polycaprolactone, and it's available under other names, too. The bags of it that've been hanging on my wall waiting for a purpose are branded "Polymorph", and I got them from Jaycar here in Australia.

I-Wei's made three videos about building the bots:

(Via.)

This Toolmonger post about a novel right-angle socket adapter led me to the interesting concept of Hobson's Coupling, in which round rods bent to a right angle transfer torque around a ninety degree corner, because they're all free to turn in their mounting holes on each leg of the coupling.

Hobson's Coupling is, as any fool can see, an obvious candidate for adaptation into a steam/air-pressure engine. The result is called an Elbow Engine, and it's a thing to behold:

There are several more on GooTube. If the concept's still not clear to you, this page about making a ten-cylinder version (only seven moving parts!) from scratch may fill you in.

Phoenix is the winner of the Trossen Robotics TRC Project Contest...

...and deservedly so.

She's a little small to really conquer the indoor environment, but the design is very scalable; I think a double-size Phoenix made with super-torque standard-sized servos or the big quarter-scale ones could scuttle up ordinary stairs quite easily.

(One could, in fact, be climbing your stairs right now. What was that noise?)

More at the forum thread.

(Via.)

[UPDATE: It's now available as a kit!]