ESP32-S3 Automated Guitar

An ESP32-S3-based automated electric guitar that physically plays programmed melodies using servomotors and solenoids, combining embedded systems, mechanical design, and digital music representation.

This project transforms a standard electric guitar into a mechatronic musical instrument, capable of executing predefined songs stored on a microSD card through real mechanical actuation.

🎸 Project Overview

Unlike digital synthesizers or MIDI-only systems, this project produces sound by directly interacting with a real guitar:

• Solenoids press the frets to define the pitch
• Servomotors strum the strings
• An ESP32-S3 coordinates timing, actuation, and song execution
• Songs are stored as simple text-based note sequences on a microSD card

The entire system is non-invasive, meaning it can be mounted and removed without permanently modifying or damaging the guitar.

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🎥 Demo Video

Short demo video of the automated guitar performing a programmed sequence:

👉 Watch the demo:
https://www.youtube.com/your-video-link

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Songs are selected via DIP switches, allowing up to 8 different melodies without reflashing the firmware.

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⚙️ Mechanical Design

Fretting Mechanism (Solenoids)

• Linear solenoids mounted along the guitar neck
• Each solenoid presses an entire fret when activated
• Compact, fast, and mechanically simple
• Designed to minimize noise and excessive force

Strumming Mechanism (Servomotors)

• One servomotor per string
• Alternating motion simulates real strumming
• Adjustable mounting system using linear rods
• Non-invasive and fully removable

All mechanical components were custom-designed and 3D printed (PLA).

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🔌 Electronics

The system is built around an ESP32-S3, selected for its performance, GPIO count, and PWM capabilities.

Main components:

• ESP32-S3 microcontroller
• MicroSD card module (SPI)
• Solenoids (fretting)
• SG90 servomotors (strumming)
• NeoPixel LEDs for visual feedback
• Dedicated 5 V and 3.3 V power regulation

Electrical Schematic

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🧩 Firmware Overview

The firmware is written using the Arduino framework for ESP32-S3 and focuses on deterministic timing and reliable actuation.

Key Concepts

• Note abstraction:

  • MIDI-like note ID
  • Associated solenoid
  • Associated servo channel

• Text-based song format: <note_midi>,<duration_ms>

• Servo position alternation to avoid double strumming

• Conditional solenoid activation for open strings

• Hardware-based song selection via DIP switches

This approach avoids full MIDI parsing while preserving musical flexibility and embedded reliability.

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📂 Repository Contents

• ESP32-S3 firmware source code
• Electrical schematics (PNG / PDF)
• Media assets (images and demo video links)

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🏆 Project Context

Developed as part of an academic mechatronics project and successfully demonstrated in a public engineering exhibition, where it received first place recognition (ExpoIngenierías 2025).

The project covers the full engineering cycle:

• Concept development
• Mechanical design
• Electronics
• Embedded firmware
• System integration and validation

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🚧 Limitations & Future Work

• Multi-string chord support
• Velocity-sensitive strumming
• Dynamic tempo control
• MIDI file parsing
• Closed-loop control for solenoids

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👤 Authors

Developed team The RAMVerries, whose memebers include:

• David González Verdejo
• Ethan Leonardo Guzmán Luna
• Sebastián León Medellín

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📜 License

This project is shared for educational and demonstrative purposes.
No warranty is provided; use at your own risk.