Hardware Components

1. Temperature Sensor (DS18B20)

   • Functionality: Monitors water temperature in real-time for TDS calculation.

   • Library Used: DallasTemperature.

2. TDS Sensor (Total Dissolved Solids)

   • Functionality: Measures the concentration of dissolved solids in water to infer its electrical conductivity.

   • Application: Ensures nutrient levels in the hydroponic solution are within the desired range.

3. pH Sensor

   • Functionality: Monitors the acidity or alkalinity of the hydroponic solution, critical for nutrient uptake by plants.

4. Water Level Sensor

   • Functionality: Detects water levels to prevent pump operation in low-water conditions and ensure consistent water supply.

Firmware Features

1. Stasis/Idle State Management

   • Objective: Reduce power consumption and prevent unnecessary motor looping caused by ESP32’s inherent loop() behavior.

   • Implementation:

     • Timer-based stalling using millis() ensures non-blocking delays.

     • System enters a transient state between active and idle periods, controlled dynamically based on sensor data.

2. Transient State Regulation

   • Sensors continuously monitor parameters and trigger actions only when thresholds are crossed or user-defined changes occur.

   • Event-driven logic eliminates unnecessary polling during stable conditions.

3. Control Mechanism

   • Actuators, such as water pumps or nutrient dispensers, are activated based on parameter deviations or user-defined schedules.

   • Safety mechanisms ensure no simultaneous conflicting actions occur (e.g., low water levels prevent pump activation).

Web Application Features

1. Secure User Authentication

   • Implementation:

     • Device ID Login to ensure only authorized users can access the system.

     • Role-based access control (RBAC) supports scalability for multiple operators managing multiple devices.

2. Monitoring Dashboard

   • Features:

     • Real-time sensor data visualisation (e.g., temperature, pH, TDS, water level).

     • Responsive UI for seamless operation on various devices.

3. Parameter Update Interface

   • Users can update desired values for parameters like target pH, temperature thresholds, and TDS levels.

   • Changes are pushed to the ESP32 in a new loop() iteration for immediate execution.

4. Data Logging

   • Historical data is stored in a cloud database, enabling users to analyze trends and optimize their hydroponic setup.

   • Backup mechanisms ensure data is not lost during communication failures.