Treasure Chest with Digital Lock
Title of Lesson: Treasure Chest with Digital Lock
Date: Fall 2025
Author's Name: Designer and Dr. David Burghardt
Grade level: 7/8
Content or Subject Area's: Informed engineering design with computer science and computer control
Duration of lesson: 6 days
General Objectives: Students will design, construct and program a treasure chest with a digital lock system that requires a specific button sequence to activate a servo motor, integrating programming logic, mechanical motion conversion, and engineering design principles to create a secure storage system with automated opening mechanisms.
Learning Outcomes: What knowledge, skills, and strategies do you expect students to gain?
(1-4 stated outcomes) After completion of the lessons, students will be able to: (use action verbs)
1. Use the informed engineering design process
2. Apply mechanical engineering principles to convert rotational servo motion into linear motion for latch mechanisms while calculating optimal positioning and movement angles.
3. Program conditional logic using button input sequences and servo control to create a secure digital lock system with feedback mechanisms.
4. Design, construct, and test an automated locking system that combines physical construction, digital programming, and mechanical motion to solve security challenges.
State Standards: (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.6: Design, compare and refine algorithms for a specific task or within a program
7-8.CT.8: Develop or remix a program that eectively combines one or more control structures for creative expression or to solve a problem
7-8.NSD.2: Design a project that combines hardware and software components
7-8.NSD.3: Identify and fix problems with computing devices and their components using a systematic troubleshooting method or guide
National standards: (ITEEA STEL Standards) End of the 8th Grade:
Standard 1: Students will develop an understanding of the characteristics and scope of technology while learning that technology is the result of human activity; technology is closely linked to creativity and ingenuity.
Standard 3: Students will develop an understanding of engineering design and will learn that engineering design is guided by brainstorming, visualizing, modeling, constructing, testing, and refining designs.
Standard 8: Students will develop an understanding of the attributes of design and will learn that design is a creative planning process that leads to useful products and systems.
Materials and Resources: Provide a list of materials and resources needed to teach the lesson
Physical Materials: Shoebox, glue gun, duct tape, Hummingbird micro:bit controller, Hummingbird rotation servo, scissors or box cutter, pipe cleaners or dowels for latch mechanism, string or flexible connectors, Hummingbird LED lights or buzzer for surprise feature, computers with Snap programming software
Resources: Servo motor tutorials, programming logic examples for button sequences, mechanical motion conversion guides, digital lock security concepts, troubleshooting flowcharts for hardware/software integration
Focusing Event: Students examine various physical security systems including combination locks, electronic door systems, and safety deposit boxes. Discussion: "How do digital security systems protect valuable items while remaining convenient for authorized users? How can we design our own treasure chest that only opens when the correct secret code is entered?" This introduces the real-world engineering problem of creating secure, automated systems that combine mechanical engineering, programming logic, and user interface design to solve security challenges.
Day by day plan
Day 1: Specifications and Constraints (40 minutes) Informed Design Phase: Specifications and Constraints
• Introduce challenge: Design a treasure chest with digital lock that opens only with correct button sequence
• Review project specifications: minimum 4-button code sequence, servo - controlled latch, surprise feature upon opening
• Discuss constraints: micro:bit button limitations (A and B only), servo rotation range, box size requirements, timing delays
• Introduce assessment rubric and informed engineering design process
• Students document initial understanding of security requirements and physical constraints
Day 2: Developing Knowledge - Servo Motors and Mechanical Motion (40 minutes) Informed Design Phase: Developing Knowledge
• Learn how position servos operate and their rotation capabilities (-100° to +100°)
• Understand rotational to linear motion conversion using flexible connections
• Practice basic servo programming: positioning servo arms at specific angles
• Students complete KSB 2: Position servo programming and movement control
• Calculate optimal servo positioning for latch release mechanisms
Day 3: Developing Knowledge - Digital Input and Programming Logic (40 minutes)
Informed Design Phase: Developing Knowledge (continued)
• Learn micro:bit button programming (A and B buttons as digital inputs)
• Understanding sequential logic and timing delays in button sequences
• Students complete KSB 4 & KSB 5: Button input programming and digital lock code creation
• Practice programming if- else statements for multi-step button sequences
• Explore security concepts: code complexity and number of possible combinations
Day 4: Ideate Solutions - Alternative Design Concepts (40 minutes) Informed Design Phase: Ideate Solutions
• Students sketch minimum of 3 alternative approaches for treasure chest locking mechanisms
• Consider dierent latch designs: dowel systems, pipe cleaner mechanisms, stringpulled latches
• Explore various surprise features: LED lights, buzzer sounds, recorded messages
• Document dierent box modifications and servo placement configurations
• Brainstorm code sequence complexity and user interface approaches
Day 5: Build Prototype - Construction and Programming Integration (40 minutes) Informed Design Phase: Build Prototype
• Construct physical treasure chest using shoebox with duct tape hinges
• Install servo motor and create latch mechanism with flexible connection
• Students complete KSB 1 & KSB 3: Treasure chest construction and servo -latch integration
• Begin programming the complete digital lock system with button sequences and servo control
• Test individual components and troubleshoot mechanical and programming issues
Day 6: Test, Evaluate, and Refine Design (40 minutes) Informed Design Phase: Test and Evaluate Design + Refine Design
• Complete the assessment rubric self- evaluation from day 1 and justify their selfassessment
• Reflect on the informed engineering design process and lessons they learned