🌞 SolaSim — Open-Source Solar Simulator

SolaSim is an open-source solar simulator for phototaxis research. It uses LED panels and "sun" tracking on a semi-circular array of LED panels to recreate realistic daylight cycles — from simple sunrise-to-sunset sequences to multi-day scientific simulations based on real latitude and date.

Built with MicroPython firmware and using a browser-based control interface, it's designed to be affordable, reproducible, and accessible to researchers and educators.

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✨ Key Features

• Solar Simulation Modes — BASIC (fixed 6 AM–6 PM) and SCIENTIFIC (astronomical calculations from latitude/date)
• Multi-Step Programs — Sequences with per-step speed, intensity, sun colour, hold/repeat, and multi-day support
• 360° Rotation Imaging — Servo-driven turntable with camera trigger for time-lapse and stills capture
• Browser-Based Control — Connect via USB from Chrome/Edge/Opera using Web Serial
• Real-Time Monitoring — Live status tiles, solar arc visualisation, interactive timeline with playhead
• Demo Mode — Preview and validate your program with an animated timeline — no hardware needed
• Profile Management — Save, load, compare, and share experiment profiles
• English & Japanese UI — Full bilingual interface with one-click toggle

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🌐 Try It Now

The web interface is hosted on GitHub Pages — no installation required:

👉 odeepllama.github.io/SolarSim/ — Open in Chrome, Edge, or Opera and connect to your device via USB.

Note: The Web Serial API requires a Chromium-based browser. See the in-app Help panel for details.

💡 No device yet? Click ▶ Demo to preview programs without hardware — great for learning the interface and validating step sequences.

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🏗️ Architecture

┌────────────────────────────────┐
│     SolaSimStudio.html         │
│     (Web Serial API)           │
│     Chrome / Edge / Opera      │
└──────────────┬─────────────────┘
               │ USB Serial
┌──────────────▼─────────────────┐
│  RP2040 Firmware               │  ← Recommended
│  (RP2040/)                     │
│  Single-file MicroPython       │
└────────────────────────────────┘
┌────────────────────────────────┐
│  ESP32-S3 Firmware             │  ← Experimental
│  (ESP32/)                      │
│  Modular MicroPython           │
└────────────────────────────────┘

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📂 Repository Structure

Folder / File	Description
SolaSimStudio.html	Web interface — browser-based control panel (USB via Web Serial)
setup.html	Setup Wizard — browser-based firmware installer for RP2040
RP2040/	RP2040 firmware — recommended, single-file MicroPython
ESP32/	ESP32-S3 firmware (modular MicroPython)
Profiles/	Example experiment profiles
docs/	Hardware documentation (pin reference, NeoPixel wiring)
CONTRIBUTING.md	Contribution guidelines for developers

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🔧 Hardware Requirements

• Microcontroller: RP2040:bit (recommended) or ESP32-S3
• LED Panels: NeoPixel/WS2812B addressable 8x8 LED matrices
• Servos: For 360° rotation platform and camera triggering (metal gear servos recommended)
• OLED Display: SSD1306 128×64 for on-device status with ESP32-S3 (optional)
• Camera Trigger: Optional Bluetooth camera trigger for use with smartphones
• 3D-Printed Parts: Housing and mounting components (Printable STL files)

📋 Full parts list: Bill of Materials — coming soon!

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🚀 Getting Started

Quick Setup (Recommended)

Use the browser-based setup wizard — no software installation required:

👉 SolaSim Setup Wizard — Open in Chrome/Edge/Opera and follow the guided steps to flash firmware and deploy files.

Manual Setup (Advanced)

If you prefer to set up manually without the wizard:

Note: The Setup Wizard supports RP2040 only. For ESP32-S3 setup, see the ESP32/ folder and flash using esptool.

1. Flash MicroPython Firmware: Flash the RP2040 with MicroPython v1.27.0 — the .uf2 firmware file is included in RP2040/. Hold the BOOTSEL button, plug in USB, and drag the .uf2 file to the drive that appears.
2. Upload Project Files: Copy main.py and main_app.mpy from RP2040/ to the device using Thonny or mpremote.
3. Connect: Open SolaSim Studio in Chrome, Edge, or Opera and click Connect to Device.

Note: SolaSim is tested with MicroPython v1.27.0 (2025-12-09). Other versions may work but are not guaranteed.

No Hardware Yet?

You can design and preview programs entirely in the browser. Open SolaSim Studio, build your program steps, then click ▶ Demo to simulate the sequence with an animated timeline playhead. Use Step/Day navigation to jump through your program and verify timing before building hardware.

💡 For developers: main_app.mpy is pre-compiled from SolarSimulator.py using mpy-cross. If you modify the source, rebuild it with:

pip install mpy-cross
mpy-cross SolarSimulator.py -o main_app.mpy

The .mpy bytecode format is required because the RP2040 has limited RAM and cannot compile the full .py file on-device without running out of memory.

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📖 Documentation

• In-App Help: Click the Help button in the web interface for a full interactive guide
• Pin Reference — GPIO pin assignments for RP2040 and ESP32-S3
• NeoPixel Wiring — LED panel daisy-chain wiring and power setup

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🤝 Contributing

This is a research project in active development. Contributions, suggestions, and bug reports are welcome! Please open an Issue to get started.

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📜 License

This project is licensed under the GNU General Public License v3.0 — see the LICENSE file for details.

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🙏 Acknowledgements

Developed at Akita International University with AI-assisted coding in VS Code, GitHub Copilot Pro (Educational access), and Google Antigravity / Claude Opus 4.6 (Thinking).

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Bringing the sun indoors for plant science 🌱