Lesson 11: Stakeholder-Centric Design and the Beaded Jewelry Project

Estimated time: 90-120 minutes | Level: Advanced

Learning Objectives

• Conduct stakeholder interviews to identify needs, wants, and constraints¹
• Extract functional requirements from interview data¹
• Design a product that meets explicit requirements (not assumptions)²
• Iterate design based on stakeholder feedback²
• Document design decisions for reproducibility and accessibility³

Materials

• Interview worksheet (provided below)
• Notebook/laptop for notes
• Access to stakeholder (or use provided scenario)
• 3dMake project scaffold
• Calipers for measurement
• Reference: master-rubric.md for design documentation standards

Extension Project: Complete Beaded_Jewelry_Unit to apply stakeholder-centric design principles in a real project context.

Why This Matters: The Design Thinking Process

Most design failures start before CAD. They happen because:

• Assumption Problem: Designer assumes what users need without asking
• Specification Problem: Unclear requirements lead to wasted iterations
• Accessibility Problem: Features designed without considering all users

This lesson flips the process: Listen First, Design Second¹.

The Design Thinking Pipeline

1. Empathize (Listen to stakeholder)
   v
2. Define (Extract functional requirements)
   v
3. Ideate (Sketch/prototype solutions)
   v
4. Prototype (Build in CAD)
   v
5. Test (Get feedback)
   v
6. Iterate (Refine based on feedback)

Part 1: Stakeholder Interviews (20-30 minutes)

What is a Stakeholder?

A stakeholder is anyone who will use, interact with, or be affected by your design. Examples:

• End User: Person who directly uses the product
• Maintenance Person: Someone who repairs/replaces parts
• Budget Holder: Person responsible for cost
• Safety Officer: Person ensuring regulatory compliance

Open-Ended Interview Questions

Good interview questions:

• [YES] Start with “What,” “How,” “Why”
• [YES] Don’t suggest answers
• [YES] Follow up with “Tell me more…”
• [YES] Listen for numbers, specific stories, pain points

Bad interview questions:

• [NO] “Do you like…?” (Yes/No - no detail)
• [NO] “Would you prefer A or B?” (Forced choice)
• [NO] “Don’t you think…?” (Leading question)

Sample Interview Script (Beaded Jewelry)

You’re designing a custom beaded bracelet holder. Here’s how to interview a stakeholder:

Opening:
"Hi [name], I'm designing a way to store and display beaded 
bracelets. I'd love to understand how YOU currently use bracelets 
so I can design something that works for you. Is now a good time?"

Question 1: "Tell me about your current bracelet collection. 
How many do you have? What are they made of?"

Question 2: "How do you currently store or display them? 
What works well? What's frustrating?"

Question 3: "If you could design the perfect bracelet holder, 
what would it look like? What would it do?"

Question 4: "Are there any constraints I should know about? 
(Size of your space, colors, budget, etc.)"

Question 5: "Who else might use this? How would their needs 
differ from yours?"

Closing:
"Thank you for your time. I'll design based on what you've told me 
and come back with a prototype for feedback."

Step-by-Step Interview Task

Duration: 15 minutes total

1. Prepare (5 min):

   • Choose your stakeholder or use the scenario below
   • Write 4-6 questions using the template above
   • Explain the project and get permission to take notes

2. Conduct (10 min):

   • Ask your prepared questions
   • Write down specific details (numbers, names, quotes)
   • Listen more than you talk
   • Ask “Why?” when you hear interesting responses

3. Document (Immediately after):

   • Write a 2-3 sentence summary
   • Extract 3-5 key needs/constraints
   • Identify any questions that still need answers

Scenario: If You Don’t Have a Real Stakeholder

Scenario: Meet Sarah, a jewelry enthusiast

Sarah has 15+ beaded bracelets but they’re tangled in a drawer. She wants to:

• Display them where she can see them
• Keep them organized by color/style
• Protect them from tangling
• Fit in a small space on her desk

Constraints:

• Budget: $15 materials cost
• Space: 6“ x 6“ footprint maximum
• Aesthetic: Minimalist, natural wood preferred
• Timeline: Needs it within 2 weeks

Part 2: Extract Functional Requirements (20-30 minutes)

From Interview to Requirements

A functional requirement is specific, measurable, and testable:

Functional Requirements Template

For your beaded jewelry holder, extract 5-8 requirements:

Functional Requirements:
1. Capacity: Hold _____ bracelets
2. Organization: Arrange by _____ (color/size/style)
3. Protection: Prevent _____ (tangling/damage)
4. Display: Visible from _____ (above/front/sides)
5. Dimensions: _____ mm wide, _____ mm deep, _____ mm tall
6. Material: _____ (wood/plastic/metal)
7. Accessibility: _____ (non-visual inspection method)
8. Durability: Withstand _____ (weight/use/time)

Measurable Acceptance Criteria

For each requirement, define how you’ll TEST it:

Part 3: Design the Bracelet Holder (30-40 minutes)

Design Strategy

Based on functional requirements, create a parametric SCAD model:

// Parametric Beaded Bracelet Holder
// Designed for: [Stakeholder name]
// Requirements: [List 3-5 key requirements]

// === PARAMETERS (from stakeholder requirements) ===
holder_width = 150;      // mm - width for 15+ bracelets
holder_depth = 80;       // mm - depth for stability
holder_height = 120;     // mm - height for display
num_pegs = 16;           // Number of hanging pegs
peg_diameter = 6;        // mm - bracelet hang diameter
peg_spacing = holder_width / (num_pegs + 1);

// === DESIGN ===

module base() {
  // Wooden-look base plate
  cube([holder_width, holder_depth, 10]);
}

module back_wall() {
  // Back support for stability
  translate([0, 0, 10])
    cube([holder_width, 5, holder_height]);
}

module hanging_pegs() {
  // Pegs for bracelets to hang
  for (i = [1 : num_pegs]) {
    x_pos = peg_spacing * i;
    translate([x_pos, holder_depth/2, holder_height - 20])
      cylinder(r=peg_diameter/2, h=30, $fn=16);
  }
}

module bracelet_holder() {
  // Combine all components
  union() {
    base();
    back_wall();
    hanging_pegs();
  }
}

// Main
bracelet_holder();

Customization Based on Stakeholder Feedback

Before printing, modify parameters:

Interview revealed:
- "15 bracelets is about right"
- "I like minimal spacing"
- "Natural wood color"
- "Small desk space - maybe 5 inches wide?"

Updated parameters:
num_pegs = 15;           // Exact count for their collection
holder_width = 127;      // 5 inches in mm
peg_spacing = holder_width / (num_pegs + 1);

Testing Non-Visually

# Describe the model to verify it matches requirements
3dm describe src/main.scad

# Expected output should mention:
# - 15 hanging pegs arranged horizontally
# - Base plate for stability
# - Back wall for support
# - Dimensions approximately 127mm x 80mm x 120mm

# Generate preview for tactile inspection
3dm preview src/main.scad

Part 4: Iterate Based on Feedback (20-30 minutes)

Feedback Loop

After printing a test version:

1. Measure physical parts:

   # Use calipers to verify
   - Actual width: _____ mm (design: 127mm)
   - Actual peg diameter: _____ mm (design: 6mm)
   - Actual spacing: _____ mm
   

2. Test with actual bracelets:

   • Can 15 bracelets actually hang?
   • Do they tangle?
   • Do pegs support the weight?
   • Is it stable on the desk?

3. Document feedback:

   Test Results:
   - [YES] Holds 15 bracelets comfortably
   -  Pegs slightly too thin (bracelets slip)
   - [YES] No tangling observed
   -  Wobbles slightly - needs wider base
   
   Adjustments for v2:
   - Increase peg_diameter: 6mm -> 8mm
   - Increase base_depth: 80mm -> 100mm
   

4. Iterate:

   // Modified parameters for v2
   peg_diameter = 8;        // Thicker pegs (8mm instead of 6mm)
   holder_depth = 100;      // Wider base (100mm instead of 80mm)
   

5. Reprint and test:

   • Does v2 address the issues?
   • Any new problems?
   • Is it ready for final design?

Accessible Iteration Tracking

Document all iterations in a spreadsheet or text file:

Version | Peg Size | Base Depth | Fits Bracelets | Stable | Notes
--------|----------|------------|----------------|--------|------
v1      | 6mm      | 80mm       | [YES] (14/15)     |      | Wobbles, pegs thin
v2      | 8mm      | 100mm      | [YES] (15/15)     | [YES]     | Perfect fit, stable
v3      | 8mm      | 100mm      | [YES] (15/15)     | [YES]     | With wood stain

Complete Project: Beaded Jewelry Bracelet Holder

Project Requirements

Objective: Design a customized bracelet holder based on an actual stakeholder’s needs.

Deliverables:

1. Interview Documentation (1-2 pages)

   • 4-6 interview questions asked
   • Stakeholder’s 3-5 key needs
   • Extracted functional requirements
   • Acceptance criteria for each requirement

2. Design SCAD File (bracelet_holder.scad)

   • Parametric design with all requirements
   • Clear parameters at top (easily customizable)
   • Well-commented modules
   • Matches stakeholder dimensions

3. Iteration Log (2-3 pages)

   • Version 1 test results
   • Feedback from stakeholder
   • Changes made for v2
   • Final design specifications

4. Printed Prototype (physical)

   • Demonstrates final design
   • Holds actual bracelets from stakeholder
   • Passes all acceptance criteria

5. Final Documentation (1-2 pages)

   • Design process summary
   • Stakeholder feedback quotes
   • Design decisions justified
   • Lessons learned

Assessment Rubric (0-9 scale)

Problem & Solution (0-3 points)

• Stakeholder clearly identified and interviewed
• Requirements extracted from interview (not assumptions)
• Functional requirements are specific and measurable

Design & Code Quality (0-3 points)

• SCAD code is parametric and well-organized
• Design meets all extracted requirements
• Iterations show thoughtful refinement based on feedback

Documentation (0-3 points)

• Interview process clearly documented
• Design decisions justified with stakeholder feedback
• Iteration log shows testing methodology
• Accessible description of design (3dm describe output)

Quiz - Lesson 3dMake.11 (10 questions)

1. What is the primary purpose of conducting stakeholder interviews before design¹?
2. Give one example of an open-ended interview question and one bad (leading) question¹.
3. What is the difference between a “need” and a “want” in the design context¹?
4. How do you convert interview data into functional requirements¹?
5. What is an acceptance criterion and why is it important²?
6. Describe how you would test a bracelet holder’s capacity non-visually using measurements².
7. True or False: You can design a good product without talking to the person who will use it.
8. Explain why iteration based on real feedback is better than guessing².
9. How would you document design changes in a way that’s accessible to non-visual users³?
10. What should you do if your prototype fails a stakeholder’s test²?

Extension Problems (10)

1. Conduct interviews with 3 different stakeholders for the bracelet holder; compare their requirements¹.
2. Design 3 different bracelet holder variants for different stakeholder types (minimalist, maximalist, travel-focused)¹.
3. Create a complete functional requirements document with measurable acceptance criteria¹.
4. Build and test 2 iterations of the bracelet holder; document all changes².
5. Develop a design specification document that someone else could follow to recreate your design³.
6. Conduct a “design review” with your stakeholder; document their feedback and your responses¹.
7. Create a manufacturing specification: tolerances, materials, assembly instructions, quality checks².
8. Build a customer feedback tracking system; document what works and what could be improved¹.
9. Design an accessibility checklist for the bracelet holder: non-visual inspection, measurement-based testing, assembly ease³.
10. Write a comprehensive design case study: from initial interview through final product, including all iterations, feedback, and lessons learned^{1 2 3}.

Summary: From Interview to Design

The 11 lessons have taken you from beginner to advanced designer. This final lesson shows you that the best designs start with listening, not assuming.

The Full Journey

1. Lessons 1-3: Foundation (setup, primitives, parametric code)
2. Lessons 4-5: Verification & Safety (AI checking, physical safety)
3. Lessons 6-7: Applied Projects (keycap, phone stand)
4. Lesson 8: Advanced Design (tolerance, interlocking, complex assemblies)
5. Lesson 9: Automation (batch processing, scripting)
6. Lesson 10: Mastery (troubleshooting, QA, testing)
7. Lesson 11: Leadership (listening to stakeholders, designing for real users)

Next Steps After This Lesson

You’re now ready for:

• [YES] Professional product design workflows
• [YES] Customer-driven development
• [YES] Small-batch manufacturing
• [YES] Open-source design contributions
• [YES] Teaching others these skills

References

1. Design Thinking Process - IDEO - https://www.ideo.com/perspectives/design-thinking ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12 ↩13

2. Functional Requirements in Product Design - https://www.productschool.com/blog/requirements/ ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9

3. Accessible Design Documentation - https://www.a11y-101.com/design/inclusive-documentation ↩ ↩2 ↩3 ↩4 ↩5