Bionic Arms: How Robot Hands Help Real People
In 2013, a 7-year-old boy named Leon McCarthy was born without fingers on one hand. His dad found free plans on the internet for a robotic hand built with a 3D printer. He built one for just $5. It worked — Leon could pick up a pencil and high-five his friends. Today, thousands of children around the world use 3D-printed prosthetic hands because of volunteers who share these designs for free.
What You'll Learn
In this lesson you will: • Learn what a prosthetic arm is and what it does • Discover how myoelectric arms receive signals from the body • Meet real people who design prosthetics for kids • Match arm parts to what each one does
What Is a Prosthetic Arm?
A prosthetic arm is an artificial arm made to replace one that is missing or damaged. People can be born without a limb, or lose one in an accident or illness. Prosthetic arms have been around for a very long time. Ancient Egyptians made prosthetic toes from wood and leather more than 3,000 years ago! Today's prosthetic arms are made from lightweight plastic, carbon fibre, and tiny computers that make them move almost like a real arm — and they keep getting better every year.
How Robot Arms Move
Your muscles send tiny electrical signals every time you try to move. Sensors placed on the skin above the arm's attachment point can detect these signals. When you think 'close hand,' your arm muscles fire a small electrical pulse. The prosthetic arm's sensors pick that up, a tiny computer reads the signal, and motors in the fingers curl them closed — all in less than one second! This type of arm is called a myoelectric arm. 'Myo' means muscle in Greek. The more a person practises, the better their brain and the robot arm learn to work together.
Your brain is always sending tiny electrical signals through your nerves and muscles. Myoelectric prosthetics listen to those signals — they are like a telephone call from your brain to the robot hand!
Kids Who Design and Use Prosthetics
Young engineers are changing the world of prosthetics: The e-NABLE community is a global group of volunteers who 3D-print free prosthetic hands for children in more than 100 countries. Many of the designers are students. A teenager named Isabel Dowd designed a waterproof prosthetic so her sister could use it at the beach — because most prosthetics cannot get wet. You do not have to be a grown-up to solve big problems. Engineers of all ages use the design process: look at the challenge, imagine a solution, build it, test it, and improve it.
Flashcards — click each card to reveal the answer
Match each prosthetic arm part to its job.
Terms
Definitions
Drag terms onto their definitions, or click a term then click a definition to match.
What does a myoelectric prosthetic arm use to know when to move?
What material did Leon McCarthy's dad use to build his son's first prosthetic hand in 2013?
Design Your Own Helper Hand
Imagine you are a biomedical engineer designing a special prosthetic hand for a specific person. 1. Decide who you are designing for: a musician, a soccer player, a painter, or someone you know. 2. On paper, draw an outline of the hand. 3. Choose 3 things your hand must be able to do (examples: grip a guitar neck, kick a ball, hold a thin paintbrush). 4. For each ability, draw or label a special feature that would make it work (example: 'soft rubber fingertips so it grips a smooth cup without slipping'). 5. Give your design a name. 6. Write two sentences: who it is designed for and how it helps them specifically. 7. Share your design — great engineers always explain their ideas out loud to others.
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