Robotic Arm Design Challenge
Lesson Plan
Title: Robotic Arm Design Challenge
Date: Fall 2025
Author's Name: Dan Thomas and Dr. David Burghardt
Grade Level: 7/8
Content or Subject Area's: Informed engineering design with computer science and computer control
Duration: 8 days (40-minute periods)
General Objectives:
Students will design, construct, and program a robotic arm made from cardboard that includes at least three joints powered by servo motors from the Hummingbird Kit, capable of performing an automated motion sequence to move an object from Point A to Point B using the informed engineering design process.
Learning Outcomes:
After completion of the lessons, students will be able to:
1. Use the informed engineering design process
2. Program positional and rotational servo motors using Birdbrain Snap to create coordinated multi-joint movement sequences
3. Design and construct a functional robotic arm prototype with multiple degrees of freedom using cardboard and brass fasteners
4. Apply iterative testing and refinement to optimize mechanical stability and programmed motion accuracy
(NY Computer Science & Digital Fluency Standards) End of Grade 8:
• 7-8.CT.4: Write a program using functions or procedures whose names or other documentation convey their purpose within the larger task.
• 7-8.CT.8: Develop or remix a program that effectively combines one or more control structures for creative expression or to solve a problem.
• 7-8.CT.10: Document the iterative design process of developing a computational artifact that incorporates user feedback and preferences.
• 7-8.NSD.2: Design a project that combines hardware and software components.
(ITEEA STEL Standards) End of the 8th Grade:
• STEL Standard 1 (Nature and Characteristics of Technology and Engineering): Develop innovative products and systems that solve problems and extend capabilities based on individual or collective needs and wants.
• STEL Standard 2 (Core Concepts of Technology and Engineering): Differentiate between inputs, processes, outputs, and feedback in technological systems.
• STEL Standard 7 (Design in Technology and Engineering Education): Apply a design process to solve problems in and beyond the laboratory-classroom.
• STEL Standard 8 (Applying, Maintaining, and Assessing Technological Products and Systems): Use technology and engineering tools, techniques, and materials safely and appropriately.
Materials and Resources:
Provide a list of materials and resources needed to teach the lesson:
Physical Materials:
• Corrugated cardboard sheets
• Brass fasteners
• Tape (masking or painter's)
• Low-temp hot glue gun and glue sticks
• Scissors or box cutters
• Hummingbird Kit (positional servos, rotational servos, wires, optional sensors)
• Ruler and pencil
• Storage bags or folders for parts
• Small objects for pick-and-place testing (erasers, paper clips, small balls)
Resources:
• Computers with Birdbrain Snap Programming software
• How Industrial Robot Arms Work video: https://youtu.be/P2r9U4wkjcc
• Position Servo Tutorial: https://learn.birdbraintechnologies.com/hummingbirdbit/snap/program/9-1
• Rotation Servo Tutorial: https://learn.birdbraintechnologies.com/hummingbirdbit/snap/program/10-1
• Student engineering journals/notebooks
• Assessment rubric handout
Focusing Event:
Students watch a short video showing industrial robotic arms performing tasks in factories, laboratories, and space stations. Discussion: "What tasks do these robotic arms perform that would be too dangerous, repetitive, or precise for humans? How do robotic arms move differently from human arms? What parts of the robotic arm correspond to a human shoulder, elbow, and wrist?" Students examine a diagram of a robotic arm and label the base, shoulder, elbow, and gripper. This introduces the realworld engineering problem of designing mechanical systems that can replicate human arm movements through motorized joints and programmed sequences.
Day-by-Day Plan:
Day 1: Specifications and Constraints (40 minutes)
Informed Design Phase: Specifications and Constraints
• Teacher presents the Robotic Arm Design Challenge: Design and build a robotic arm with at least 3 joints that can move an object from Point A to Point B using a programmed motion sequence
• Conduct focusing event: Watch video on industrial robot arms and discuss how they mimic human arm movement
• Review specifications: Have 3 joints; Programmed to move an object from Point A to Point B
• Review constraints: Use only provided materials (cardboard, servos); Limited class time; Must be stable and functional
• Introduce the assessment rubric and informed engineering design process
• Students document initial understanding of the challenge in their engineering journals
Day 2: Knowledge Building - Robot Arm Movement and Grippers (40 minutes)
Informed Design Phase: Developing Knowledge
• Students complete KSB 1: How Do Robot Arms Move?
• Watch video on industrial robot arms and label a diagram with base, shoulder, elbow, and gripper
• Use arrows to show how each part moves (rotation, lift, open/close)
• Compare robotic arm movement to human arm movement (write 2-3 sentences)
• Students complete KSB 2: What Makes a Great Gripper?
• Create and test two gripper styles using paper, cardboard, or LEGO
• Test grippers by picking up at least 3 different objects; Evaluate which gripper works best for each object
• Document findings in engineering journals
Day 3: Knowledge Building - Positional Servo Programming (40 minutes)
Informed Design Phase: Developing Knowledge
• Students complete KSB 3: Positional Servo Basics
• Learn how positional servos rotate to specific angles (0°, 90°, 180°) for precise joint control
• Connect a positional servo to Hummingbird and program it to rotate between 0°, 90°, and 180° with wait commands
• Experiment: What happens when you try to go beyond 180°? What happens if you move too fast?
• Take screenshots of code and paste in engineering journals
Day 4: Knowledge Building - Rotational Servo and Joint Construction (40 minutes)
Informed Design Phase: Developing Knowledge
• Students complete KSB 4: Using a Rotational Servo
• Learn the difference between positional servos (specific angles) and rotational servos (continuous spinning)
• Program a rotational servo to spin in one direction, stop, and spin in the opposite direction
• Experiment with speed control (100% vs 30%) and negative values for direction
• Students complete KSB 5: Building Strong Cardboard Joints
• Build a simple rotating joint using cardboard strips and brass fasteners
• Test and refine joint tightness; Try mounting a servo horn to see how it moves when attached
• Document joint construction techniques in engineering journals
Day 5: Ideate Solutions and Choose Optimal Design (40 minutes)
Informed Design Phase: Ideate Solutions
• Students complete the Alternative Robotic Arm Designs activity
• Draw a side view of robotic arm design including: Base, Arm segments (upper arm, lower arm), Gripper, Servo locations
• Add motion arrows to show how each part will move (rotation, lift/lower, open/close)
• Write a motion plan describing the sequence of movements needed to pick up and move an object
• Complete the Optimal Robotic Arm Design activity: Review options, set criteria (strength, range of motion, gripper capability, buildability)
• Compare designs using checkmarks or 1-5 ratings; Select optimal design and write 3-4 sentence justification
Day 6: Build Prototype (40 minutes)
Informed Design Phase: Build Prototype
• Students begin building their robotic arm prototype following their labeled sketch
• Follow Your Sketch: Cut cardboard pieces for Base, Upper arm, Lower arm, and Gripper
• Build in Sections: Assemble one joint at a time, using brass fasteners for rotation; Reinforce weak spots; Mount servos according to sketch
• Test After Each Step: Check range of motion, joint tightness, and fix problems before moving on
• Attach Everything Together: Ensure arm can stand or attach to base; Wire servos correctly; Verify each joint performs its intended motion
• Photograph progress and document construction in engineering journals
Day 7: Test, Evaluate, and Refine Design (40 minutes)
Informed Design Phase: Test and Evaluate Design + Refine Design
• Students write and test their robotic arm code
• Plan the Code: Map out motion sequence (rotate base, lower arm, close gripper, lift, rotate, release)
• Write the Code: Use Birdbrain Snap to program the full pick-and-place sequence
• Test and Observe: Run the arm through its motions; Record at least 3 problems observed (gripper hold, joint smoothness, base stability)
• Analyze Weak Spots: For each problem, ask "Why is this happening?" and identify root causes
• Plan and Apply Fixes: Reinforce cardboard, adjust servo placement, redesign gripper as needed
• Retest after each fix; Document test results, analysis, and refinements in engineering journals
Day 8: Reflection and Self-Evaluation (40 minutes)
Informed Design Phase: Reflection
• Students complete the assessment rubric self-evaluation from Day 1 and justify their self-assessment with specific evidence from their project work
• Students reflect on the informed engineering design process and lessons learned by answering reflection questions in their engineering journals: What did you learn about coding, how robotic arms work, and issues to consider when designing one? How have your own experiences influenced your design? What was the most challenging part of the project? How did your team collaborate to solve problems? If you had more time, what would you improve?