A jamming gripper is basically a balloon filled with coffee grounds. If you place the balloon over an object and apply some force, the loose coffee grounds will flow and distribute themselves around the object. When you pull a vacuum inside the balloon, the coffee grounds jam together and become solid, gripping the object.

Follow the instructions below to make your own jamming gripper!

Step 1: Materials

* 9” balloon

* 1 heaping tbsp coffee grounds

* Coffee filter

* 3D printed holder(3d file)

* Zip ties 6" - 2x

universalGripper.stl
Download View in 3D

Step 2: Tools

* Scissors
* Pen
* Super glue
* Funnel or a folded piece of paper
* Aquarium tubing
* Some means of generating vacuum, I used Programmable-Air, but you can use a vacuum pump, or just suck with your mouth.

Step 3: Mark

Mark the coffee filter with the size of the holder base.

Step 4: Cut

Cut the coffee filter along the marking. We'll need the cutout circle in the next step.

Step 5: Glue

Glue the cutout circle to the base of the holder. Make sure to cover the edges only. Otherwise, the glue will block the filter and no air will be able to pass through.

Step 6: Fill

Fill the balloon with 1 heaping tbsp of coffee grounds using the funnel or paper.

This can get a little bit tricky. It might help if you pre-stretch the balloon by blowing it up and chop off the neck of the balloon. You will probably need a friend to hold the balloon for you.

Step 7: Stretch

Stretch the balloon over the 3d printed holder. Careful not to puncture the balloon while doing this.

Step 8: Pull

Pull the balloon over the holder until the holder is fully inside the balloon. You want the coffee powder to be loose inside the balloon. Err on the side of too loose instead of too tight.

Step 9: Zip Ties

Zip tie the balloon over the holder. Make sure to tighten the zip tie over the grooves in the holder. Depending on the length, you might need to use the zip ties in series to increase their length.

Step 10: Cut

Cut the excess balloon and zip ties.

Step 11: Connect the Tube

Now connect a tube to the 3d printed holder. That's it! You're done!!

If you suck on the tube, the coffee particles jam together and become almost solid. Let some air back in, and they flow freely. This allows you to grip objects by placing the gripper over something and then sucking on it to make the coffee particles jam around it and pick it up. Letting air back in drops the object. I'm using Programmable-Air to control the airflow to this gripper.