# System Overview

HydroponicOne is a professional-grade, open-source IoT hydroponic control system. It is designed to bridge the gap between hobbyist DIY projects and industrial automation.

![HydroponicOne Architecture](../assets/diagrams/HydroponicOne-architecture-master.png)
*Figure 1: High-level System Architecture*

```mermaid
graph TD
    subgraph "Edge Layer (ESP32)"
        Device["IoT Node (ESP32)"]
        Sensors["Environment Sensors (I2C/Analog)"]
        Actuators["Relays / Pumps"]
        Device <--> Sensors
        Device <--> Actuators
    end

    subgraph "Communication Layer (MQTT)"
        Broker["MQTT Broker (HiveMQ/Mosquitto)"]
    end

    subgraph "Cloud / Intelligence Layer (Fastify)"
        Backend["Fastify API Server"]
        InfluxDB[("InfluxDB (Telemetry)")]
        PostgreSQL[("PostgreSQL (State/Config)")]
        Backend <--> InfluxDB
        Backend <--> PostgreSQL
    end

    subgraph "Presentation Layer (React)"
        Frontend["Vite + React Dashboard"]
    end

    %% Data Flow
    Device -- "Telemetry (MQTT v5)" --> Broker
    Broker -- "Forward" --> Backend
    Backend -- "Real-time Update (Socket.io)" --> Frontend
    Frontend -- "REST Commands" --> Backend
    Backend -- "Control Dispath (MQTT)" --> Broker
    Broker -- "Command" --> Device
```


## 🏗️ Core Architecture

The system is divided into four main layers:

### 1. Edge Layer (ESP32 Firmware)
Our custom firmware is built for the **ESP32**. It handles sensor acquisition, local calibration logic, and direct relay control. It features a modular sensor architecture that avoids heap fragmentation.

### 2. Communication Layer (MQTT)
Data is moved across the system using the **MQTT** protocol. This ensures low-latency, reliable delivery of telemetry and commands, even in poor network conditions typical of greenhouses.

### 3. Data & API Layer (Node.js/Fastify)
The backend acts as the brain of the system:
- **Telemetry Ingest**: Validates and routes sensor data to **InfluxDB**.
- **State Management**: Manages device settings and logs via **PostgreSQL (Prisma)**.
- **Command Dispatch**: Routes user actions from the dashboard to the devices.

### 4. Presentation Layer (React/Vite)
A modern, responsive dashboard built with React 19 and Vite. It providing real-time visualization of your grow environment and full remote control over your hardware.

## 📡 What's Inside?

For a deeper dive into each component, refer to the technical reference:
- 🛠️ [**Backend Technical Reference**](./reference/BACKEND.md)
- ⚛️ [**Frontend Technical Reference**](./reference/FRONTEND.md)
- 📡 [**Network Topology Map**](../README.md#tech-stack)

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### Next Steps:
Ready to build? Move on to [**Step 2: Hardware Setup**](./02_HARDWARE_SETUP.md).