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Robotic Gripper Runs on Coffee and Balloons - Updated with video Answered

I'm just on FIAH with these Topics. But this one's cool too.

Via ScienceDaily: A collaboration between researchers from Cornell, University of Chicago, and iRobot has resulted in a robot gripper that conforms to practically any object. From the article:

Here's how it works: An everyday party balloon filled with ground coffee -- any variety will do -- is attached to a robotic arm. The coffee-filled balloon presses down and deforms around the desired object, and then a vacuum sucks the air out of the balloon, solidifying its grip. When the vacuum is released, the balloon becomes soft again, and the gripper lets go.

This sounds like another hi-tech device that could easily be duplicated by a DIYer. All you need is a balloon, coffee grounds, and a vacuum pump.

Update 2 November: Found the video! It gives a much better idea of how the thing works.

Via, image from same.


The gripper has been duplicated, now. Posted in the MAKE blog overnight:

Steve Norris of Norris Labs presents his low-cost implementation of Cornell's jamming-skin-enabled balloon gripper using a Handi-Vac as a vacuum source.[via BotJunkie]

Yep, I saw that last night but decided to sleep instead of mentioning it on here. :)

'This sounds like another hi-tech device that could easily be duplicated by a DIYer--All you need is a balloon, coffee grounds, and a vacuum pump.'

... and a robotic arm. :P

I quite fancy making one to attach to my own arm. Would make for an interesting prosthetic.

Unfortunately, I think it would also be incredibly impractical - I can't imagine what material you could construct the outer membrane from that would protect it from the stresses of everyday usage.


I hadn't thought of that! How flexible is it (I have no idea)?

.  Very close to nylon, rayon, &c. You may be able to use thinner, more flexible fibers than what is used in bullet-resistant vests and house wraps.

Oh! That's what that weather barrier stuff is made out of? Cool.

>Considers posting a DIY bulletproof vest out of house wrap...but people might think it's serious<

> Considers posting a DIY bulletproof vest out of house wrap...but people might think it's serious
. What's your point? Chuck Darwin roxorz!

. IIRC, Tyvex (or similar) is often used for a general-purpose barrier and Kelvar (or similar) is used in hurricane/tornado areas.

You could have used rubber for protection, but having even a tiny tear or puncture would cause a problem.

You could have two layers; an inner, airtight layer, plus an out layer to deal with wear and tear.

I'm surprised this works with a balloon - I would have thought it would be too tight to allow the coffee to fit around stuff.

(Oh, and I think their inspiration came from bean-bag camera "tripods" - some of them have small pumps to suck* the air out and lock them into shape.)

*Yes, I know.

I just added a video of it in action, which gives a much better indication of how it works. It's a lot squishier than I was thinking.

Interesting question! If you built the bag and vacuum nozzle as an integrated unit, then you could use an impermeable material like neoprene (sacrifice an old wetsuit or laptop bag) on the outside, sealed against the rim of the nozzle. A thin latex inner bag would keep the particulates contained and permit proper vacuum operation.

Do you think that'd be sufficiently resistant to stuff like rips, tears, pokes, and so on? I've handled neoprene before, but was thinking of the stresses I know I've put my limbs through, and I'm not convinced it would be sufficient over the long term to protect against a world filled with such...pokey...angles and edges and sticks and scissors and so on (perhaps it would be just fine and I'm being nit-picky). Not to mention your friends coming up behind you and squishing your oh-so-cool-feeling arm to death. Maybe you'd just have to be careful, and adjust activities with the arm on accordingly?

Ah, but remember, it's not the whole arm, just the "hand" -- the gripping part. I'm not sure what's used as a covering on modern prosthetics (time for a Web search :-), but neoprene isn't a terrible choice.

(Whoops, that's what I meant...hand, not arm :P )

It'd be awesome if that worked - that's simple and pretty inexpensive. The next time I lose an arm, I'll be sure to try it. :D

NEW WAY TO GET ANSWERS: post that it can't be done. :D

perhaps a cheap prosthetic hand for under-developed countries? with a manual pump?

just attach the balloon device to the end of something that would fit on a stump, then use something like the preassure pump from a sphigmomonometer to vacuum out the air from the ballon.

wonder what else could be used besides coffee? corn starch maybe?

"As for the right particulate material, anything that can jam will do in principle, and early prototypes involved rice, couscous and even ground- up tires. They settled on coffee because it's light but also jams well, Amend said. Sand did better on jamming but was prohibitively heavy."

*sphygmomanometer Can't you spell anything right? :P

You must be waiting for him to hit the fan.

sphigmomonometer  and sphygmomanometer both pass the spellcheck so you both must be right.

my spell check didn't flag it as incorrect.

at least i knew it was an actual word as opposed to using "you know...the squishy bit from that blood pressure thingy"

for me the ibles spell check does squat, and for some reason the rich text editor blocks my iespell checker.

Good answer! Complicated words which you usually hear spoken rather than written can be hard to get right. I was a bit surprised that Merriam-Webster online corrected me (see the link I posted to Caitlinsdad).

Neither one was in mine, what kind of spell check are you using?

spellcheck button in the comment editor, never use it.  Then again it may be broken in Chrome, Vista Business.

Spell-check isn't all its cracked up to be...


Anything with small, irregular grains. Those soft buckwheat-filled stress balls would work quite well. You need a slighly gas-porous membrane (like a latex balloon) so that the vacuum can pull air out of the ball.


7 years ago

I'll remember this for Robotics class ;)