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!
* 9” balloon
* 1 heaping tbsp coffee grounds
* coffee filter
* 3D printed holder
* zip ties
* Programmable-Air kit
* scissors
* pen
* super glue
* funnel or a folded piece of paper
Mark the coffee filter with the size of the holder base.
Cut the coffee filter along the marking
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.
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.
Stretch the balloon over the 3d printed holder. Careful not to puncture the balloon while doing this.
Pull the balloon over the holder till 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.
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 use the zip ties in series to increase their length.
Cut the excess balloon and zip ties.
Congrats! The jamming gripper is complete. Connect it to the output of Programmable-Air kit.
Upload the Jamming Gripper example to Programmable-Air board. Now the gripper can be actuated by pressing the blue button on-board.
To use the gripper, place the balloon over an object like a pen and apply some force. You should feel the coffee grounds flowing and distributing themselves around the object. Now, press the blue button on Programmable-Air. This should pull a vacuum inside the balloon, making the coffee grounds jam together and turn solid. Now lift the balloon(while holding the button), and the object with it. Release the button to drop the object. Isn’t that gripping!