Picture of DIY Universal Robot Gripper

There are a lot of different kinds of robot grippers (end effectors). The most common strategy when designing a robot hand is to try to replicate the human hand. However, in 2010 researchers at Cornell University and University of Chicago developed a unique approach. They created an amorphous gripper that was able to mold itself to the object that it wanted to pick up. This kind of gripper is much more versatile. 

In this project, I am going to show you how to make your own DIY universal gripper for your robots. 

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Step 1: Background: How It Works

Picture of Background: How It Works
mechanical drawing gripper2.jpg
This gripper works because of a process that is called "jamming." When a granular material such as coffee is compressed, it becomes very rigid. As the pressure increases so does the amount of friction between the individual grains. This effectively locks the grains in place.

You may have observed this phenomenon while handling bags of coffee grounds. A vacuum packed bag of coffee grounds is rock hard as long as the seal remains intact. But as soon as the seal is broken, the coffee become soft and pliable and can be poured like a fluid. This process happens with many granular materials such as rice, couscous and even sand.

We are utilizing this process to make an amorphous robot gripper. A balloon is filled coffee grounds and attached to an air hose. When balloon is slightly pressurized the grounds are loose and easily rearranged. By pressing the balloon against an object, the grounds will move around it and take its shape. But when the air is sucked out of the balloon, the grounds are compressed and grip the object. The rubber surface of the balloon also helps to keep a hold of the object.

Here is a video from Cornell University that explains the process:

Step 2: Materials

Picture of Materials
Here are the tools and materials that you will need for this project:

Plastic Funnel
Coffee Grounds
Duct Tape
Air Hose/Tubing
Thin Cloth
Small Plastic Tube (optional)

Air pump for pumping air into and out of the balloon

Nice Instructable!

Irwan210 months ago

Hi, this is cool stuff. You just remind me of Doraemon (cat robot from Japan) anime. Now I understand how he is able to hold things in his round hand. Looks like the author himself knows his stuff pretty well.

MicioGatta Irwan26 months ago

Me too!!

DIY Hacks and How Tos (author)  Irwan210 months ago
Ardumedes9 months ago

Very nice! Good instructable and helped make a boring afternoon interesting!

ASCAS10 months ago

Nice! Will flour work?

DIY Hacks and How Tos (author)  ASCAS10 months ago
Maybe. A lot of materials will work. Coffee just works well because is has such a low density.
macrumpton11 months ago

I wonder if you could use a large hypodermic syringe to suck the air out? That would be a much smaller and cheaper device then a vacuum cleaner and you could even control the plunger with a motor or solenoid.

DIY Hacks and How Tos (author)  macrumpton11 months ago
Yes. In fact there is another instructable that uses that method.
The only issue that you may have is being able to suck out enough air to create a proper vacuum. The larger the balloon is the more air you will need to remove.
TechnoWombat11 months ago

Instructable by Davros?

Vampyra6511 months ago

This is a pretty cool idea :o)

DemolisionWolf11 months ago
A coin!? It can pick up a coin!? This is incredible
the batman11 months ago
There's already a piece of Cloth
rtudeschini11 months ago
Very cool. I'd add a small piece of cloth to act as a filter, to prevent the coffee from being sucked to the hose. And for an electric robot, you could attach a large syringe to a spindle, to generate both the negative and positive pressures needed to the system. Thanks for the amazing instructable!
Silence11 months ago

OMFG ! Its a Dalek gripper !!

mikeasaurus11 months ago

These grippers are so neat


rkrishnan711 months ago

Great idea, excellent presentation and exceptional diction - you could easily be a news anchor but we are glad you chose to be a Maker instead!

rich_291011 months ago
doraemon? is that you?
DIY Hacks and How Tos (author)  rich_291011 months ago
Sorry but I am not really familiar with that cartoon.
craftclarity11 months ago

This is one of the most interesting developments in robotics I've seen in at least the last fifteen years. It's nice to see roboticists taking such a lateral approach to solving the many problems inherent in developing grippers for arms and the like. SUPER COOL! Thanks for sharing this.

samjohn11 months ago
Very cool!
freakhanya11 months ago
very innovative gonna try this. can u kindly add up the link for corresponding pneumatic.
Bobey11 months ago
Wow I will do this and pick up the WORLD
C-R-E-811 months ago
Very Cool but cant it damage the vacuum cleaner after long periods
DIY Hacks and How Tos (author)  C-R-E-811 months ago
It isn't much worse than normal use. But for something that you would use regularly, you would want a good quality vacuum pump that is design for this kind of task. Many robots are already pneumatically powered, so you would probably use the air pump that is already powering the robot.
the batman11 months ago
This is a very creative and unusual way for a robot hand to pick things up, I love it
dan300811 months ago

mmm, seems like alot of nice coffee missed out on... lol

brill ible :)

DIY Hacks and How Tos (author)  dan300811 months ago
No it was terrible coffee.
Jdsardone11 months ago

Very cool idea, and simple to make.

Also, so as not to confuse people, in step 1, first paragraph you say "As the pressure increases so does the amount of friction between the individual grains. This effectively locks the grains in place."

But I think you mean as pressure decreases (aka vacuum forms) the friction goes up, locking the grains in place"

DIY Hacks and How Tos (author)  Jdsardone11 months ago
I guess my wording was a little ambiguous. What I meant was "as the grains are pressed against each other (which happens as a result of the change in air pressure)."
texagon11 months ago
simple yet effective, great idea.