Automatic Guitar Tuner
Arduino-based automatic guitar tuning system using FFT frequency detection, PID control, and a motorized tuning mechanism. Redesigned into an ergonomic handheld product with integrated display.
Skills
Overview
Personal project to build an automatic guitar tuning system that detects string frequency via microphone, processes the signal using FFT, and automatically adjusts tuning pegs with a motorized mechanism.
The project evolved from a breadboard proof-of-concept to a redesigned handheld product with an ergonomic enclosure, onboard display, and user-friendly interface.
How It Works
System Architecture
- Frequency Detection — Microphone captures string vibration, Arduino processes audio using FFT algorithm with hardcoded target frequencies for each guitar string
- PID Feedback Loop — System calculates error between detected and target frequency, uses PID control to determine motor correction
- Motor Control — 12V DC motor with custom 3D-printed adapter interfaces directly with tuning peg for precise adjustments
Original breadboard prototype proving out embedded system design
Product Redesign
After validating the concept, I redesigned the system for manufacturability and user experience:
Handheld Enclosure
- Ergonomic grip designed in SolidWorks for comfortable handheld operation
- Integrated onboard LED display for real-time tuning feedback
- Compact housing consolidates all electronics and battery
- User-friendly interface eliminates need for external equipment
The redesign transformed the proof-of-concept into a compact, market-ready device suitable for batch assembly.
Cross-section view of handheld guitar tuner enclosure, engineered for ergonomics and manufacturability
Technical Implementation
Hardware:
- Arduino Uno microcontroller
- Microphone for audio capture
- 12V DC motor with custom 3D-printed tuning peg adapter
- LED display for user feedback
Software:
- FFT algorithm for real-time frequency analysis
- PID feedback loop for stable, accurate tuning control
- Hardcoded target frequencies for standard guitar tuning (E-A-D-G-B-E)
Mechanical Design:
- SolidWorks CAD modeling for enclosure design
- 3D-printed housing and adapter components
- Ergonomic form factor optimized for single-handed operation
This project demonstrated the full product development cycle from proof-of-concept prototyping through redesign for manufacturability.