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DIY Model Robot Hand STEM Activity

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Create a functioning model robot hand that uses mechanical principles to make its fingers curl when cords are pulled. This project is a hands-on introduction to concepts like joints, force, and motion.

  • Total Time: 90 minutes

Ingredients

  • 1 piece of corrugated cardboard, 12 inches by 18 inches, for the palm and five fingers
  • 5 flexible drinking straws, each 8 inches long, for finger guides
  • 5 pieces of smooth cotton or nylon cord, each 24 inches long, one for each finger
  • 5 small pony beads, 1/4 inch to 3/8 inch wide, for cord handles
  • 1 wooden craft stick, 4.5 inches long, for the wrist support
  • 1 small cardboard rectangle, 2 inches by 3 inches, for the back wrist brace
  • 1 bottle of white craft glue, 4 fluid ounces, or 12 glue sticks for a low-temperature glue gun
  • 1 pair of sharp scissors, for cutting cardboard and straws
  • 1 pencil, for tracing and marking
  • 1 ruler, at least 12 inches long, for straight measurements
  • 1 small hole punch, 1/8 inch or 1/4 inch, for cord openings
  • 1 low-temperature glue gun, optional, for faster assembly
  • 1 self-healing cutting mat or 1 thick piece of scrap cardboard, for protecting the table
  • 1 pair of safety glasses, for cutting and punching
  • 1 pair of adult-size work gloves, optional, for rough cardboard edges

Instructions

  1. Cover the table with a cutting mat or thick scrap cardboard.
  2. Draw a palm shape about 5 inches wide and 6 inches tall onto the cardboard. Draw five fingers, each 1 inch wide, with lengths of 3.5 inches for the index finger, 4 inches for the middle finger, 3.75 inches for the ring finger, 3 inches for the pinky, and 3.25 inches for the thumb.
  3. Cut around the palm and each finger with steady scissor strokes.
  4. On each finger, mark three lines across the width. Place the first line about 1 inch from the fingertip, the second 1 inch below that, and the third 1 inch below the second when the finger is long enough.
  5. Cut fifteen straw sections, each 3/4 inch long.
  6. Place one straw section across each marked joint and secure both ends with a small amount of glue.
  7. Punch one small hole near the fingertip of every finger. Thread one 24 inch cord through the three straw guides, beginning at the fingertip and moving toward the palm.
  8. Arrange the fingers across the top of the palm with a small gap between each one. Glue the lower end of each finger to the palm.
  9. Place the 2 inch by 3 inch cardboard rectangle behind the lower palm and glue the 4.5 inch craft stick across it as a handle.
  10. Guide all five cords down toward the wrist, keeping them separate. Tie a pony bead to each cord end.
  11. Hold the wrist stick in one hand and pull a bead gently with the other.
  12. If one finger bends sharply, loosen the cord and move the nearest guide with a little fresh glue.
  13. Once all five fingers move, add a small dab of glue beside each cord knot on the back of the palm.
  14. Let the hand rest for 30 minutes before gentle testing, or let white craft glue dry overnight for the strongest hold.

Notes

Keep the hand away from rain and damp spaces as moisture can damage cardboard. The model can last several months with careful indoor use.

  • Author: marata-alibanti
  • Cook Time: 60 minutes
Free Crochet Pattern
FREE
Pattern!
Free Crochet Pattern
FREE
Pattern!