Note: This fun project is provided by Festo as part of their appearance for Maker Camp 2014. Watch a video of Festo’s Fin Gripper in action here.

Make yourself a gripper that is based on a fish’s tailfin!

There is a lot to be discovered in nature. We can learn quite a bit from plants and animals.

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Left and right, up and down — Jasmina moves the joystick to control Robotino. She guides the device to a little bottle that she then tries to pick up using Robotino’s “claw”. On her first attempt the bottle slips out of Robotino’s grasp, but her second attempt is a success. “Well done,” says Johannes Stoll, who is explaining Robotino to the three junior reporters Jasmina, Sandro and Ellena.

Image of a fish skeleton from Wikipedia

Robotino is made up of a pneumatic drive and three gripping fingers. What is special about these gripping fingers is that they move in just the same way — left and right, up and down — as the tail of a bony fish. If a person pushes against a tail fin with his or her finger, it doesn’t bend away. On the contrary. It bends towards the finger. In other words the gripping fingers are very adaptable. “We call this the Fin Ray Effect,” explains Johannes Stoll. In this way, it is possible for the gripper to pick up objects that are very different in size.

The three junior reporters have come to Festo to learn something about bionics. Bionics is a made-up word. It is a combination of the words biology and robotics. Bionics studies ways to transfer natural phenomena to technology. After all, over the course of many millions of years nature has developed techniques that humans can learn from. Here it is important to carefully observe plants and animals. For example, swim flippers were modeled on a duck’s feet. Pliers, which can be found in every modern household, were inspired by stag beetles. And the model for Robotino’s gripper was the tail fin of a bony fish.

After the three junior reporters have all had a chance to operate Robotino and picked up a few objects, they build a gripper themselves out of paper. You can make one yourself using this template!

Optional extension: Maker Camp discovered a way to put two fin grippers together to make a claw. Check it out in action in this video.

Project Steps

Print out the pattern

Download the template here. There are two per page.

If you cannot print your template on cardstock, glue the whole pattern on construction paper.

Cut it out

Cut out the 4 individual pieces.

Fold it

Fold the ribs and the fin along the dotted lines.

Put it together and squeeze!

Apply glue to the gray areas of the fin. Glue each matching rib in place. For example, “Rib 1” on both “Glue Rib 1” spots.

Join the bottom of the fin together as in the picture.

Pinch a bottom corner to get it to “grip.” Put your thumb on the bottom and other fingers on the side. (Your fingers should be below Rib 3.)

Give it a squeeze!

Extension: Create a claw!

Build a second fin.

Tape the bottom of Fin 1 to the side of Fin 2. They should meet up as in the picture, with the corner of Fin 1 lined up with the level of Rib 3 on Fin 2. When you squeeze the two bottoms together, the claw will close.