Project Overview

An IoT-based automated plant watering and notification system using a NodeMCU (ESP8266). The system monitors soil moisture levels via a sensor, and when dryness is detected, it notifies the user through the Blynk app. Optionally, it can activate a water pump or grow light via a relay module to irrigate plants automatically.

 Core Components

• NodeMCU ESP8266 microcontroller (built‑in Wi-Fi)

• Analog soil moisture sensor (e.g. YL‑69 with LM393 module)

• Relay module (for water pump or similar actuator)

• Optional: DS18B20 or DHT11/22 for temperature/humidity sensing

• Blynk mobile app (for monitoring and control) 

 How It Works

1. NodeMCU connects to Wi-Fi and initializes Blynk

2. Reads soil moisture via analog pin

3. Converts analog reading into a moisture percentage

4. Sends this data to Blynk app (e.g. gauge widget on a virtual pin)

5. If moisture falls below a user-defined threshold (set via Blynk slider), the system:

   • Sends a notification message

   • Activates the relay to power a mini pump (or other actuator)Optional: Temperature sensor readings can be used to add more controls

6. Push-button control and scheduling logic can also be implemented for manual override or local actions (in more advanced setups) 

 Typical Features & Behavior

• Real-time moisture monitoring on smartphone

• Adjustable watering threshold via Blynk

• Automated actuation (pump or light) based on sensor data

• Alerts/notifications for low moisture levels

• Optional local manual control (buttons, LEDs, physical overrides)

• Optional integration of temperature/humidity sensors for smart decisions 

 Wiring Overview

• Soil Moisture Sensor

  • Power: 3.3V or 5V to sensor

  • GND to NodeMCU GND

  • Analog output → A0 (via resistor divider if needed) Relay Module

• • IN from digital pin (e.g. D0, D4)

  • Relay contacts to control external device (e.g. pump) powered by 12 V or appropriate supply Optional Temp Sensor

• • DHT11/22 or DS18B20 connected to a data pin (e.g. D14/OneWire) 

 Example Software Logic

• Include Wi-Fi and Blynk libraries, define ssid, password, and auth-token

• Set pins, initialize sensors and relay

• Use a timer (e.g. SimpleTimer library) to:

  • Read soil moisture every few seconds

  • Send moisture percentage to Blynk

  • Check threshold and trigger relay when necessary

• Use BLYNK_WRITE(Vx) to update settings like watering threshold or manual mode

• Optionally handle notifications (Blynk.notify(...)) and buzzer/LED feedback 

 Suggested Software Flow

 Applications & Skills Demonstrated

• Building IoT systems with ESP8266 + Blynk

• Reading analog sensors and converting values to meaningful units

• Relay control for external devices

• Remote sensor monitoring and threshold-based automation

• Mobile notifications and user interactions via widgets

 Why It’s Useful

• Ideal for automating small-scale plant watering

• Accessible, low-cost hardware components

• Extensible: add environmental sensors, local controls, logging

• Helps conserve water and reduces plant maintenance effort