Build a Robot Hand

Introduction

Do you know anyone who has had a hand or an arm injured in an accident? What if you could build them a robotic hand to help them accomplish everyday tasks like writing, picking up a glass, or opening a door? This activity will show you how to build a simple robotic hand using common household materials.

Materials

• Modeling clay. The clay can be reusable, air-dry, or oven-dry.
• Drinking straws
• String
• Tweezers
• Small rubber bands
• Paper clips
• Scissors
• Needle
• Cardboard tube
• Assorted objects to grasp
  
  
  

What Happened?

Using the materials suggested in this activity, you should be able to build a robotic hand that can pick up small, lightweight objects. Objects that are slightly squishy or have rough textures (like a block of foam) may be easier to pick up than objects that are hard and smooth (like a table tennis ball). You may find it difficult to pick up heavy objects (like a coffee mug) because the straws are not sturdy enough and will bend backwards. The shape and variety of objects that you can pick up will depend heavily on how many fingers your hand has and how you arrange them. For example, you could build a hand that is very good at picking up paper cups, but has a hard time with table tennis balls, or vice versa. Building a robot hand that can easily pick up a wide variety of objects, like a human hand can, is a very difficult challenge that professional engineers are still working on to this day!

Digging Deeper

Your hand is made up of bones, muscles, joints, and tendons. The bones provide the rigid structure for the hand, like the straws in this project. The joints provide places for the fingers to bend, like the notches in your straws. The tendons pull on the joints to make the different segments bend, just like the string in your robot hand. The muscle in your robot hand is still provided by a human, since ultimately you are the one pulling on the paper clips. Real robotic hands have electric motors in them that act like muscles.

The science of developing robotic hands, along with other artificial limbs and organs, is called prosthetics. Scientists, engineers, and doctors work together to develop artificial body parts as replacements for people who lose organs or limbs due to accidents or disease. Try searching online for other types of prosthetic limbs and organs that have been developed. You might be amazed at what you find!

For Further Exploration

• Can you build a hand out of sturdier materials that can lift heavier objects? A trip to the hardware store might help you discover what materials you could use.
• Can you expand your robotic hand so it includes other joints? What about a wrist, or an entire arm including an elbow and shoulder?

Related Resources

Project Ideas

Links

• Blog Post: Grasping with Straws: A Robotic Hand

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