TC

The GuitarJam

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Engineering · Design · HFE

A comprehensive product development project creating a Bluetooth-enabled, clip-on display for guitarists. The device mounts to the guitar headstock and shows chord charts within the player's natural line of sight, solving the problem of awkward phone-based learning.

Course: ENP 64 Methods for Human Factors | Completed: Fall 2022

The Problem

Learning guitar from phones creates multiple pain points: players must stop playing to scroll through chord charts, looking down at a phone causes neck strain (60° deviation from upright), and constant task-switching disrupts practice flow. Observational studies confirmed these issues affect both beginners and experienced players.

The Solution: GuitarJam

A clip-on E-ink display that provides chord progressions, metronome, and learning tools right where players naturally look—at the guitar neck. Connects via Bluetooth to a companion app for song selection and customization.

Core Innovation: Moves information from phone to headstock, reducing neck angle from 60° to 15° while eliminating task-switching.

Design Process

User Research

  • Developed user personas (teenage intermediate player, 11-year-old beginner)
  • Interviewed 5 guitarists to validate problem and gather feature requests
  • Conducted task analysis observing novice learning a song
  • Identified pain points: 3-4 scrolling interruptions per song, neck strain, chord lookup delays

Anthropometric Analysis

Applied human measurement data to determine physical specifications:

  • Screen size: Calculated viewing distance (3 feet) and minimum text legibility to determine 8.4cm × 8.4cm E-ink display
  • Grip mechanism: Used grip strength data and torque calculations to design handle requiring only 20% of 5th percentile female grip strength
  • Ergonomic impact: Quantified neck angle reduction (60° → 15°) to reduce cervicalgia risk

Interface Design

  • Mobile app: Designed linear flow for pairing, song search, customization (key/BPM), and upload
  • Device display: Maximized information density while maintaining readability—chord name, progression, timing, metronome
  • Design philosophy: Simple, functional, elegant—no unnecessary features

CAD Prototyping

Created SolidWorks model with:

  • Ball-and-socket joint for angle adjustment
  • Spring-loaded clamp (1.5cm grip handles from calculations)
  • Modular construction for repairability
  • Material selection optimized for low-cost manufacturing (injection-molded polymer)

User Testing

Tested interactive Figma mockups with 5 participants. Validated usability of app flow and device interface with strong positive reception and minimal confusion.

Key Design Decisions

E-ink Display: Chosen for perfect contrast, outdoor visibility, battery efficiency, and eye comfort (vs. backlit LCD).

Companion App Model: Offloaded complex functions (tuner, song library) to phone while keeping device simple and focused.

Safety-First Clamping: Designed grip mechanism accessible to lower-percentile grip strengths to ensure broad usability.

Minimal Moving Parts: Limited to clamp and ball joint to reduce failure points and manufacturing complexity.

Impact & Outcomes

Ergonomic Improvement: 75% reduction in neck deviation during practice, significantly lowering cervicalgia risk.

Cognitive Load Reduction: Eliminated task-switching and memory burden, allowing focus on technique and timing.

User Validation: Testing confirmed the solution addresses real pain points without introducing new usability issues.

Key Takeaways

Domain expertise accelerates design. Starting from personal experience as a guitarist provided deep problem understanding, which research validated and refined.

Vertical thinking matters. Considering hardware, software, manufacturing, and user experience holistically creates better products than optimizing components in isolation.

Unspoken needs are critical. Users requested "better chord charts" but didn't mention neck pain—observation revealed this hidden requirement.

Constraints drive creativity. E-ink's slow refresh rate ruled out certain features but enabled superior battery life and visibility.

Skills Demonstrated

  • User research (interviews, personas, task analysis)
  • Anthropometric analysis and biomechanical calculations
  • Interface design (Figma wireframing, visual hierarchy)
  • CAD modeling (SolidWorks mechanical design)
  • Physics-based engineering (spring mechanics, torque, leverage)
  • Design-for-manufacturing principles
  • User testing and iteration
  • Systems-level product thinking
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