What’s not to love about animatronics? Just peel back any puppet’s silicone skin to uncover a cluster of mechatronic wizardry that gives it a life on the big screen. I’ve been hunting online for a good intro to these beasts, but I’ve only turned up one detailed resource–albeit a pretty good one–from the Stan Winston Tutorials series. Only 30 seconds into the intro video, I could feel those tentacles waking up my lowest and most gutteral urge to create physical things. Like it or not, I was hooked; I just had to build one… or a few. This is how you built a very real animatronic tentacle.
If you’re getting started in this realm, I’ll be honest: the Stan Winston Tutorial is actually a great place to start. In about two hours, instructor Richard Landon covers the mindset, the set of go-to components, and the techniques for fabricating a tentacle mechanism with a set of garage tools–not to mention giving us tons of real-film examples along the way .
We also get a sneak peek into how we might build more complicated devices from the same basic techniques. I’d like to pick up exactly where he left off: 4-way two-stage tentacles. And, of course, if you’ve picked up on just how much I like a certain laser-cuttable plastic at this point, I’m going to put a modern twist on Landon’s design. These design tweaks should enable you to build your own tentacle and controller with nothing more but a few off-the-shelf parts, some Delrin, and a laser cutter… Ok, fine, a couple 3D printed parts managed to creep their way in too.
In a good-ol’ engineers-for-engineers fashion, I’m doing something a little different for this post: I’m finishing off this series with a set of assembly videos, a BOM, and the original CAD files to make that beast on the front page come to life. As for why, I figured: why not? Even though these mechanisms have lived in the robotics community and film industry for years, they’re still lacking the treatment of a solid, open design. This is my first shot at closing that gap. Get yourself a cup of coffee. I’m about to give you every bleeding detail on the-how-and-why behind these beasts.
[ivorjawa] is putting on a haunted house this Halloween that we really don’t want to go to. His robot tentacle is already supremely creepy, and we’re assuming it will only be more frightening once it’s covered in fabric and foam rubber.
Each tentacle can move on two axes thanks to four steel cables running through this strange Geiger-esque contraption. In the base of the tentacle are two stepper-motor driven cylinders that take up slack on one cable and draw out another cable. Two of these control boxes, driven by a stepper motor and an Arduino motor shield, allow the tentacle to reach out and grab in any direction. You can check out the mechanics of the build on [ivorjava]’s flickr
On a semi-related note, even though we’re more than a month out from Halloween, we should have more Halloween builds in our tip line by now. If you’re working on one, don’t be afraid to send it in, even if you’re just showing off a work in progress.
Soft robots are a peculiar wing of technology. They don’t use frames and motors for locomotion, but as the name implies they are made of soft materials. They move by pumping fluid — it could be air or liquid — in and out of bladders that push or pull against the body itself. [Matthew] points out that fabricating soft robots has traditionally been a time-consuming and difficult task. He’s trying to make it easier by 3D printing molds into which soft robots can be cast. This way the parts can be designed in CAD, converted to a mold design, and pushed to a 3D printer.
The object with which he’s been testing the technique functions like an octopus tentacle. The image at the bottom left illustrates the internal structure, with rings separated to allow the appendage to flex, and tubes running parallel to the appendage to provide the force needed to bend it. Above that image you can see one of the molds that was used, and the final product is on the right. The video after the break shows a demonstration of this bending left and right as air is pumped in using the bulb of a blood pressure cuff (or Sphygmomanometer for those paying attention).
Tentacles have inspired fear and respect in humans long before anime came into the scene. Sailors shivered in their timbers at the thought of the great Kraken, or that octopus from 20,000 Leagues Under the Sea. It’s no surprise to know that humans have been trying to harness this fear and respect in technological form since the mid-20th century at least.
The fascinating world of tentacle robots has come a long way. It used to be that every breakthrough in tentaclebot technology had to be justified with either a military or misogynistic application, as demonstrated in this remarkable MIT project from 1968.
Thankfully our society has moved on since those misguided times, and while there is still the ever-present military-industrial complex to push for tentacled combat-omatons, forward-thinking people on the domestic front like [festo] demonstrate that at least some of us want to use tentacle robots for peace, love and food handling.