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Bones & Muscles Articulated Bionic Flex-Hand

Source:

Construct a wearable cardboard bionic hand with straw finger bones and string tendons. Pulling string tendons bends the fingers; flex sensors on a glove mirror the hand movement using micro servo motors.

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Props & Materials Required

  • •Cardboard hand cutout template
  • •Plastic straws (finger bone segments)
  • •Nylon string / thread (muscle tendons)
  • •4x SG90 micro servo motors
  • •Flex sensors or potentiometer glove
  • •ESP32 / micro:bit V2 controller

Step-by-Step Instructions

1

Assemble Cardboard Bones

Cut straw segments for phalanges (finger bones) and tape them onto cardboard fingers.

2

Thread Tendon Strings

Thread nylon string through the straw bones, securing one end at the fingertip and leaving the other end free at the wrist.

3

Pull Tendons to Grip

Pull the string tendon — watch the cardboard finger curl into a grip! Release string — finger straightens!

4

Robotic Servo Mirror Mode

Put on the flex-sensor glove. Bend your human finger — the servo motor pulls the bionic hand string automatically! Speaker explains bone-muscle movement.

Why It Works & Notes

Understanding how bones (rigid straws) and muscles/tendons (pulling strings) work together to move joints is best learned by building a mechanical model. Connecting flex sensors shows how robotic prosthetics work.