Devanshsingh-svg/Oniongaurd

An offline-first, dual-core ESP32 climate controller designed to retrofit rural onion storage sheds (Kanda Chawl) and prevent post-harvest rot and sprouting. # 🧅 OnionGuard — Smart IoT & AI Post-Harvest Onion Storage System > An intelligent, low-cost post-harvest storage solution leveraging IoT environmental monitoring and predictive machine learning to detect early rot, optimize airflow, and extend onion shelf life up to 160 days. --- ## 📌 Overview Post-harvest onion loss accounts for substantial agricultural waste due to fungal decay, premature sprouting, and uncontrolled humidity. **OnionGuard** continuously tracks microclimatic variables and volatile gas emissions inside storage structures to alert farmers and automate active ventilation before visible decay spreads. --- ## ⚡ Key Features - **Early Rot Prediction:** Detects volatile organic compounds and gases ($H_2S$, $NH_3$, $CO_2$) to forecast spoilage 24–48 hours before physical damage occurs. - **Dynamic Microclimate Control:** Automated fan/blower trigger based on configurable temperature and relative humidity (RH) thresholds. - **Shelf-Life Estimation:** ML-driven classification (*Healthy*, *At-Risk*, *Spoiled*) calculating remaining safe storage duration. - **Farmer-Centric Alerts:** Real-time mobile/web dashboard with SMS notifications and multi-language support. - **Off-Grid Compatibility:** Low-power ESP32 architecture optimized for solar panel and battery integration. --- ## 🛠️ System Architecture ### 1. Hardware Layer - **Microcontroller:** ESP32 (Wi-Fi / Bluetooth Low Energy) - **Climate Monitoring:** DHT22 / BME280 (Temperature & Relative Humidity) - **Gas Sensing Array:** - `MQ-136` / `MQ-137` — Hydrogen Sulfide ($H_2S$) & Ammonia ($NH_3$) detection - `MQ-135` — Air quality and Carbon Dioxide ($CO_2$) concentration - **Actuation:** 12V DC / BLDC exhaust ventilation fans via relay module - **Power Unit:** 12V solar charge controller with Li-ion battery backup ### 2. Software & Intelligence Layer - **Firmware:** C++ / Arduino IDE with FreeRTOS multitasking - **Cloud & Backend:** Node.js / FastAPI backend wi …