🌸 ROS Cycle

Free Period Tracker & Menstrual Cycle Calendar

Track Your Cycle — Privately, Transparently, and on Your Terms

✨ Features · 📐 How It Works · 🚀 Getting Started · 🛡️ Privacy · 🤝 Contribute

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ROS Cycle is an open-source, privacy-first menstrual cycle tracker that runs entirely on your device. No accounts. No cloud. No telemetry. Just honest, math-backed predictions you can actually understand.

Unlike commercial trackers that hide their logic behind black-box algorithms, ROS Cycle is built on transparent, explainable mathematics — so you always know how and why a prediction is made.

ROS Cycle is a tracker, not a diagnostic tool. Predictions are estimates based on your inputs, not medical advice.

ROS Cycle uses a two-layer mathematical model: a deterministic core anchored to your cycle data, layered with probabilistic reasoning to represent real biological uncertainty.

For any calendar date Dₙ, the cycle-relative day is:

CycleDay(Dₙ) = (Dₙ − D₀) mod μ_C

Converts any absolute date into a repeating cycle position, anchoring all phase calculations.

Ovulation is never certain. ROS Cycle models it with a Gaussian distribution:

P_ov(d) = exp( −(d − (μ_C − 14))² / 2(σ_C + δ)² )

• δ ≈ 1–2 days of biological noise is always included
• Confidence smoothly decreases the further a day is from the expected ovulation center
• Output: a likelihood value between 0 and 1 per cycle day

No false certainty. Just gradients that reflect reality.

Confidence = 1 − (σ_C / μ_C)    [clamped to 0–1]

# Clone the repository
git clone https://github.com/YOUR_USERNAME/ros-cycle.git

# Navigate into the project
cd ros-cycle

# Install dependencies
npm install

# Start the app locally
npm start

⚡ Everything runs in your browser or on your machine. No backend, no server, no sign-up.

ROS Cycle was built around a core principle: your health data belongs to you, and only you.

• ✅ All computation is local-only
• ✅ No accounts required
• ✅ No cloud storage, no sync, no telemetry
• ✅ No behavioral tracking or background learning
• ✅ Fully auditable open-source code
• ✅ Predictable, deterministic outputs given the same inputs

ROS Cycle includes an optional symptom awareness checklist for common PCOD-related symptoms.

• Summarizes symptom count
• Encourages you to speak with a healthcare professional when appropriate
• Does not influence cycle predictions
• Does not perform any diagnosis

• 🗓️ 12-month cycle calendar
• 🎯 Probability-informed fertile windows
• 📈 Ovulation likelihood peaks
• 📉 Cycle confidence indicators
• 📄 Local-only exportable PDF reports

Contributions are warmly welcome! We especially value work that:

• 💡 Improves explainability of predictions
• ♿ Enhances accessibility
• 📊 Extends visualization clarity
• 🔒 Preserves the privacy-first architecture

# Fork the repo, then:
git checkout -b feature/your-feature-name
git commit -m "feat: describe your change"
git push origin feature/your-feature-name
# Open a Pull Request 🎉

⚠️ Feature proposals requiring cloud storage or opaque inference models will be carefully reviewed to ensure they align with ROS Cycle's core values.

ROS Cycle is an educational and informational tool. Menstrual cycles are influenced by stress, illness, hormonal conditions, medications, and lifestyle factors. All predictions are estimates and may vary significantly.

Always consult a qualified healthcare professional for medical concerns.

MIT License — free to use, modify, and distribute.

See LICENSE for full terms.