Turning a Plant's Electrical Signals Into Music: A Bio-Sonification Build

📖 Project Overview

This repository contains the resources for a bio-sonification instrument: a system that captures the faint bioelectric signals of a houseplant and converts them into real-time MIDI music. It covers the full signal chain — analog acquisition, an Arduino-based processing stage, and a Raspberry Pi sound engine — from circuit design to a working, headless installation.

Features

• Analog Front-End: Op-amp based acquisition circuit (CA3140) with low-pass filtering for clean bioelectric signal capture.
• Arduino Signal Processing: Real-time sampling, digital smoothing, and threshold-based MIDI note/chord generation.
• Raspberry Pi Sound Engine: Python MIDI bridge feeding a SunVox-based synthesizer for continuous, evolving sound.
• Autostart Setup: Scripts for a fully headless installation that starts on boot.

test_plante.mp4

🔗 Explore the Full Project

For a detailed walkthrough of the project, including the analog design, signal processing algorithm, and testing results, check out the full article:

This article includes:

• Signal Characterization: Understanding plant bioelectric activity and the noise challenges around it.
• Circuit Design: The full analog front-end, gain and filter calculations.
• Firmware Walkthrough: How raw sensor readings become MIDI chords and melody.
• Results and Testing: Filter performance, noise rejection, and sensor validation.

🚀 Getting Started

Files Included

1. Arduino:

   • Arduino/code_arduino_2_capteurs: Main firmware — signal acquisition, filtering, and MIDI generation for two sensor channels.
   • Arduino/detect_manu: Standalone test sketch for validating raw sensor readings before running the full system.

2. Raspberry Pi:

   • RaspberryPi/bio_bridge.py: Python script that bridges Arduino serial MIDI messages to a virtual MIDI port.
   • RaspberryPi/start_bio_instrument.sh: Startup script that launches SunVox and the MIDI bridge.
   • RaspberryPi/bio_instrument.desktop: Autostart entry for headless boot-time launch.

3. Documentation:

   • Documentation/hardware_list.txt: Full bill of materials.
   • Documentation/setup_guide.txt: Step-by-step installation and configuration guide, including troubleshooting.
   • Documentation/schematics/: Circuit schematics, Arduino pinout, and component datasheets.

How to Use

1. Download the Files:

   • Clone this repository or download the files directly from the GitHub repository.

2. Build the Acquisition Circuit:

   • Follow the schematics in Documentation/schematics/ to assemble the analog front-end on a breadboard.

3. Flash the Arduino:

   • Open Arduino/code_arduino_2_capteurs in the Arduino IDE and upload it to an Arduino Nano (or compatible board).

4. Set Up the Raspberry Pi:

   • Install SunVox and Python dependencies (pyserial, python-rtmidi), then run RaspberryPi/bio_bridge.py.

🛠️ Installation and Setup

1. Circuit Assembly:

   • Wire the CA3140-based acquisition stage as shown in the schematics, one channel per plant sensor.

2. Firmware Upload:

   • Flash the Arduino with the provided sketch and verify sensor readings via the Serial Monitor.

3. Software Setup:

   • Install SunVox on the Raspberry Pi, configure the virtual MIDI port, and enable autostart using the provided .desktop and .sh files.

🧪 Testing and Validation

1. Sensor Validation:

   • Verify that contact with a plant produces a measurable, variable signal on the Arduino's Serial Monitor.

2. Filter Validation:

   • Inject test signals at different frequencies to confirm the low-pass filter rejects mains-frequency noise while preserving the biological signal band.

3. Full System Test:

   • Confirm MIDI messages reach SunVox and trigger audible notes in response to plant activity.

📝 Documentation and References

• SunVox: Lightweight modular synthesizer used for sound generation — warmplace.ru/soft/sunvox
• python-rtmidi: Python MIDI I/O library (MIT license)
• pyserial: Python serial communication library (BSD-3-Clause license)

🔧 Future Improvements

• Move from breadboard to a custom PCB.
• Improve sensor design and long-term contact reliability.
• Add more simultaneous plant channels for a larger "plant orchestra."
• Battery-powered, fully portable enclosure.

📫 Contact and Support

For questions or support, please open an issue on this GitHub repository or contact [email protected].

📖 Additional Resources

• SunVox
• Arduino IDE
• CA3140 Datasheet

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