DIY: Robotic Hand | Tinkerer Box Blog

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Robotic Hand

Stem Activities

Ages: 9-12

Less than 30 minutes

Grownup needed

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With just three common materials—straws, cardboard, and string—kids can create a bionic robotic hand that moves and bends. This fun STEAM activity helps children learn about the structure of the human hand while enhancing their engineering and creative thinking skills!

Materials Needed

Cardboard (40cm x 20cm, 15cm x 20cm, two pieces 5cm x 5cm, 12cm x 4cm, 8cm x 4cm)
Pencil
Scissors
Craft knife
Drinking straws
Paint
Paint palette
Paintbrush
Ruler
Five 25cm lengths of string
Double-sided tape
Glue

An assortment of craft supplies is arranged on a light wood-grain table, laid out in preparation for a project. The supplies include various sizes of cut cardboard pieces, a utility knife, scissors, string, colorful straws, a ruler, a paintbrush, a pencil, tubes of paint or glue, a flower-shaped paint palette, and a bottle of white glue. This image depicts the materials gathered for a crafting activity.

Step-by-step tutorial

Step 1

Take the 40cm*20cm cardboard and draw the outline of your hand and forearm with a pencil. Keep the arm shape simple and practical to allow for movement and functionality.

Two hands are positioned on a piece of brown cardboard on a light wood-grain table. One hand holds a blue pencil and is tracing the outline of a finger from the other hand onto the cardboard. This image shows the process of creating a template or pattern by tracing a hand or finger shape onto cardboard.

Step 2

Cut along the drawn lines with scissors.

Two hands are shown working with a piece of brown cardboard on a light wood-grain table. One hand holds the cardboard, which has several lines drawn on it. The other hand holds a pair of black scissors and is in the process of cutting along one of the lines. This image illustrates the step of cutting cardboard along pre-drawn lines, likely for a craft or construction project.

Step 3

Now paint your cardboard in your favourite colours!

A hand-shaped piece of cardboard lies on a light wood-grain table. Another hand holds a paintbrush with orange paint and is applying the paint to the 'fingers' of the cardboard cutout. This image shows the process of painting a cardboard hand, likely for a craft project.

Step 4

Using a ruler, measure and mark the distances between joints on the dried cardboard (2-3cm between each joint point).

A silver-painted cardboard hand cutout rests on a light wood-grain table. A hand holding a pencil is using a clear ruler to draw straight lines across the fingers of the cardboard hand. This image captures the step of marking precise lines for cutting or folding on a craft project.

Step 5

Following these marks, fold the finger joints towards the palm (use a ruler to help with folding). The palm section is now basically complete.

Two hands manipulate a silver-painted cardboard hand cutout on a light wood-grain table. The 'fingers' of the cardboard hand have been partially cut and are being gently bent. A clear ruler is positioned alongside the cuts, likely used as a guide for the bending or cutting process. This image shows the stage of shaping the cardboard hand for a craft project.

Step 6

Take the 15cm*20cm cardboard and use a ruler to measure along the 20cm edge, marking at 5cm, 10cm, and 15cm.

On a light wood-grain table, a piece of brown cardboard is being marked with a pencil. A hand uses a clear ruler to guide the pencil, marking three 5cm increments along the cardboard's edge. This image shows precise measurement and marking for cutting or folding cardboard, likely for a craft or DIY project.

Step 7

Fold the marked rectangle inward at these marks.

Two hands are folding a piece of brown cardboard along a scored line on a light wood-grain table. A clear ruler is placed along the fold, assisting in creating a crisp, straight edge. This image demonstrates the process of folding cardboard precisely, likely for constructing a small box or other cardboard structure.

Step 8

Number your cardboard sections 1, 2, 3, 4 in order, then draw a 13cm*3cm rectangle inside sections 2 and 4.

A piece of brown cardboard lies flat on a light wood-grain table. It's divided into four sections, numbered 1 through 4. Sections 2 and 4 have rectangular outlines drawn within them, measuring 3cm wide and 13cm long, as indicated by labels. This image appears to show a template or plan for cutting or folding the cardboard.

Step 9

Carefully cut out these two rectangles using the craft knife - these are crucial parts of your handle!

A piece of brown cardboard, divided into four sections and numbered 1 through 4, rests on a light wood-grain table. Rectangular holes have been cut out of sections 2 and 4. The remaining sections, 1 and 3, are solid. This image likely depicts a stage in a craft or DIY project involving cardboard construction.

Step 10

Fold the cut rectangular pieces along the creases to form a cuboid and glue the joints. Then glue the two 5cm*5cm square cardboard pieces to each end. Set your completed handle aside to dry.

Two hands hold a small, rectangular box constructed from brown cardboard against a light wood-grain background. The box is open at one end, revealing a decorative pattern or design on the interior bottom. The hands gently support the box, showcasing its simple construction. This image likely illustrates a finished or nearly finished DIY cardboard craft project.

Step 11

Cut the drinking straws into sixteen 1cm pieces, five 4cm pieces, and one 2cm piece.

On a light wood-grain table, several small, colorful plastic tubes are arranged in three groups. A loose pile of pink tubes is on the left, a neat row of yellow tubes is in the center, and a single pink tube is on the right. These tubes appear to be components for a craft or educational activity.

Step 12

Cut five 1*1.5cm pieces from spare cardboard and attach one 25cm string to each.

Close-up of two hands holding a small piece of cardboard. A length of white string or twine is being glued or attached to the cardboard using a clear adhesive. The focus is on the process of securing the string to the cardboard.

Step 13

Begin assembly by gluing the dried cuboid handle to the middle of the arm.

A simple robotic arm crafted from cardboard lies on a light wood-grain surface. The arm is painted silver and has segmented fingers, giving it a robotic appearance. A small, unpainted cardboard box is attached to the arm, serving as a control panel or joint. This image likely depicts a children's craft project or a simple robotics model.

Step 14

Glue the 1cm straw pieces between the joints, with 13 pieces needed for the palm side. Then glue the four 4cm straws to the middle of the palm (as shown).

A cardboard robotic arm, painted silver, rests on a light wood-grain table. Pink and yellow plastic tubes are attached to the hand section, representing finger joints or mechanical components. A small, plain cardboard box is affixed to the arm, likely symbolizing a control unit. This image showcases a completed DIY robotic hand craft project, likely made by a child.

Step 15

Make a hole below the second crease of the thumb (counting from top) large enough for a straw. Insert the 2cm straw and secure with glue.

Two hands are working on a cardboard robotic hand against a light wood-grain background. One hand holds the silver-painted cardboard cutout of the robotic hand, while the other hand carefully places small pink tubes onto the hand shape. Yellow tubes are already affixed to the palm area. This image captures the process of assembling a children's craft project.

Step 16

Glue one 4cm straw to the handle side near the thumb.

Two hands are assembling a cardboard robotic arm on a light wood-grain surface. One hand holds the silver-painted cardboard arm, which has pink and yellow tubes attached to the hand section. The other hand is attaching a yellow tube to a small, plain cardboard box, which will likely act as a joint for the arm. This image shows the construction phase of a DIY robotic arm craft project.

Step 17

Turn to the back of the hand. You'll see two straw openings - glue the remaining three 1cm straws between these openings, equally spaced.

Two hands are shown constructing a cardboard robotic arm on a light wooden surface. One hand holds the gray-painted cardboard arm, while the other hand affixes small pink tubes to the arm section. A small, plain cardboard box sits on the table, likely used as a component of the arm's mechanism. This image illustrates the process of making a robotic arm from cardboard, likely a children's craft activity.

Step 18

Glue the 12cm4cm cardboard piece at the wrist joint and the 8cm4cm piece on the forearm to prevent bending.

Two hands are assembling a cardboard robotic arm on a light wood-grain table. The arm is partially painted silver, with the hand section more fully painted than the forearm. Small pink tubes are attached to the hand, and a piece of unpainted cardboard with printed designs is affixed to the forearm. A small cardboard box acts as a joint, connecting a yellow straw to another part of the arm. This image captures the construction process of a DIY cardboard robotic arm, likely a children's craft project.

Step 19

Attach the small cardboard pieces to each finger and thread the strings through the straws. Note: the thumb string goes through the back straw.

A partially constructed cardboard robotic hand is being worked on against a light wood-grain background. The hand is painted silver, with pink tubes attached to the fingers and yellow tubes along the palm. White strings are threaded through the hand and connect to a simple cardboard box that serves as the wrist. A hand is seen in the image, threading a string through one of the pink tubes. This image captures the process of creating a functional cardboard robotic hand, likely a science or engineering project.

Step 20

Thread the strings from the back through the handle-side straw, bottom to top.

Two hands are in the process of assembling a cardboard robotic arm on a light wood-grain surface. The arm is made from plain brown cardboard and sections painted silver. White strings are being threaded through the wrist area, which is a small box-like structure. The hand portion, visible in the background, has pink and yellow tubes attached to the fingers and palm, also connected by strings. This image shows the construction of a DIY robotic hand, likely a science or engineering project.

Step 21

Put your hand through the handle and have someone help tie the strings to your fingers (or try it yourself).

A hand is demonstrating a completed cardboard robotic hand against a plain, light-colored background. The robotic hand is made of silver-painted cardboard with pink and yellow straws attached to the fingers and palm. White strings connect the fingers to a small cardboard box worn on the back of the hand, acting as the control mechanism. The hand is positioned to show how pulling the strings manipulates the cardboard fingers. This image showcases a finished DIY robotic hand project, likely created for educational or demonstration purposes.

Step 22

Your robotic hand is now complete - try picking up some objects. Have fun experimenting!

A hand operates a DIY cardboard robotic hand, gripping a clear plastic ruler against a light-colored background. The robotic hand is constructed from silver-painted cardboard, with pink and yellow straws along the fingers. White strings connect the fingers to a small cardboard box worn on the back of the hand, serving as the control mechanism. The hand is demonstrating the robotic hand's ability to grasp and hold an object. This image likely illustrates a science or engineering project demonstrating principles of robotics.

The Science Behind It:

Our hands are made up of bones, muscles, joints, and tendons. Bones provide the rigid structure for the hand, similar to the straws in this project. Joints allow the fingers to bend, just like the notches in the straws. Tendons pull the joints, enabling different parts to bend, just like the strings in the robotic hand. The "muscles" in the robotic hand are still powered by humans, as the one pulling the strings is you!

Who Are We?

We’re a passionate team of scientists, engineers, and educators dedicated to delivering hands-on fun. Our mission is to inspire creativity and confidence in the next generation of young innovators.