The Mechanical Robotic Arm

Unit Objectives
By the end of this unit, students will be able:
  • To demonstrate how the muscles in an arm function.
  • To compare and contrast the human arm with a robotic arm.
  • To articulate a rationale for the importance of using teamwork to complete a project
  • To identify the steps in the engineering design process

Activity One: The Mechanical Arm 1

Materials List
  • hole punch
  • 2 large paper clips
  • marker
  • 1 medium brass fastener (1 in. [2.5 cm])
  • paper cup
  • smooth string (39 in. [100 cm]) (for example, fishing line)
  • 1 straw (cut into 1-in. [2.5-cm] lengths)
  • 1 strip of corrugated cardboard (about 2 x 4 in. [5 x 10 cm]) (corrugated cardboard has grooves in the middle, like a cardboard shipping box)
  • 1 strip of corrugated cardboard (about 2 x 8 in. [5 x 20 cm])
  • tape



Activity One: The Mechanical Arm 2

Materials List
  • Wooden craft sticks
  • Drill
  • Small brass paper fasteners
  • Assorted materials

  • Drill holes through the craft sticks as shown in the diagram. Each student will need four drilled sticks and four brass paper fasteners. Dampening the sticks before drilling can reduce cracking the wood.
  • Have students assemble robot arms as shown in the illustration.


  • Tell them to try to pick up a pencil or some other object with the arm. They will find the task difficult.
  • Next, tell the students to design some sort of end effector for the end of the arm that will enable them to pick up the object. Students should make their end effector and attach it to the ends of the arm with glue.
  • Evaluate their work by having them demonstrate picking up the object.


Content Review
Learners review and interact with the following the following online resources:

Group Design Challenge: Build Your Own Artificial Arm
Through this lesson, students will:
  • Learn design concepts.
  • Learn teamwork.
  • Learn problem solving techniques.
  • Learn about simple machines.

Support Materials

  • 3" wide and approx. 22" long strips of cardboard-- 5 or so
  • Binder clips (different sizes)-- 8 or more
  • Brads-- @10
  • Clothespins-- 6
  • Craft sticks--10-15
  • Fishing line-- 3-4 feet
  • Hangers-- 1 or 2
  • Paper clips (diff. Sizes)-- 10-15
  • Pencils-- 3-4
  • Rubber bands (different sizes)--15
  • Tape-- clear and masking (partial rolls should be fine)
  • Twine-- 3-4 feet
  • Various size scraps of cardboard--10 assorted

As a hook, show learners the following video:

  • Engage the learners in the following discussion: Assume that you are a mechanical engineer working on the design of an artificial arm for someone who has lost function of his or her arm/hand. What are some of the design considerations you will have to take into account? What capabilities will you want to design into the arm/hand? What capabilities of the human arm/hand might you be willing to give up in your design?
  • You are a member of a team of three or four students, working together to design and build a robot arm out of the materials which are provided to you
  • The robot arm must be at least 18 inches in length, have at least three degrees of movement, and be able to pick up an empty Styrofoam cup. The support materials - the powerpoint and worksheets can help explain the task.
  • Your team must agree on a design for the arm and identify what materials will be used. Your team should draw a sketch of your agreed upon design prior to construction. Part of the teamwork process is sharing ideas and determining which design your team will use.
    There is no "right" answer to the problem - your team's creativity will likely generate an arm that is unique from the others designed in your class.


The Challenge
Gifted Student
Independent Research
Students can do additional research on the biomechanics of arms. Findings from their research can be incorporated when students build their artificial arm.
Attention Deficit Disorder
Cue Cards

Time Tracker Visual Timer and Clock
  • The directions for each of the projects (Robotic Arm 1; Robotic Arm 2; and Building an Artificial Arm) are printed – in large print – on cue cards. One direction or step per card. A teacher or peer tutor can read the directions aloud with this student.

  • The time tracker assists the student in knowing how much time is left with a given project.
Learning Disabilities
Concrete Presentation & Broken Down into Smaller Steps
Videos can be used to show students each step of the building process. The videos show each stage of the construction process, so that EACH step is demonstrated in a concrete model form.

Lesson Assessment (Using Google Forms)