[HBRobotics] Two-Stage Tentacle Mechanisms Files and Instructions Online

[jsam...@pobox.com]

I found this posting on one of my robot email lists. He talks about laser cutting Delrin. Is that an acceptable material on the Hack Factory laser cutter? And the arm is pretty cool, too.

- Jeff

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Hey folks,

Back in August, I brought a prototype two-stage mechanism that I'd been adapting from the Stan Winston Tutorial Series.

After a few months of documentation after-hours, the almighty Bill-of-Materials and original CAD files are up online. I've also put up

• A mental model behind the movement of these mechanisms
• a tour of the controller
• a step-by-step assembly guide for both tentacle and controller

This mechanism can be constructed from a collection of 

• (mostly) laser-cut Delrin (Acetal Homopolymer) plates
• (a few) 3D printed cable conduit holders
• some off-the-shelf parts

Cheers--and let me know if you make anything cool based on this design!

Joshua Vasquez

PS: if you're looking to dig deeper into laser-cutting functional prototypes, have a look at the 3-part guide on laser-cut Delrin I wrote over the last year.

[Sebastian Wiers]

Delrin is a name brand acetal polymer, so should not contain any
chlorine. If in doubt, you could melt a bit onto a wire and then hold
it in a blowtorch flame to check if there is any green in the flame
(indicating chlorine) - that is the suggested test for unknown
materials.

And yeah, I really liked the arm design. I remember seeing something
similar (but scaled up) used as the structure for Jabba the Hutt's
tail in a documentary on pupeteering.

Would be neat to add a third flexing segment controlled by twist
(motorcycle throttle style) out at the tip of each tentacle.

-Seb