Circuit Documentation

Summary

This circuit is designed to measure soil moisture levels using a soil moisture sensor and a Soil Moisture Module. The data is processed by a NodeMCU V3 ESP8266 microcontroller, which reads the analog values from the sensor and outputs the soil moisture percentage to the serial monitor. The circuit is powered by a 12V power supply, which is regulated to the required voltage levels using a buck converter.

Component List

Soil Moisture Sensor

• Description: Measures the moisture level in the soil.
• Pins: Positive, Negative

Soil Moisture Module

• Description: Interfaces with the soil moisture sensor and provides analog and digital outputs.
• Pins: Positive, Negative, Analog, Digital, Ground, VCC

NodeMCU V3 ESP8266

• Description: A microcontroller with built-in Wi-Fi capabilities, used to read sensor data and process it.
• Pins: A0, GND, VU, S3, S2, S1, SC, S0, SK, 3V3, EN, RST, Vin, D0, D1, D2, D3, D4, D5, D6, D7, D8, RX, TX

Buck Converter

• Description: Steps down the voltage from the 12V power supply to the required levels for the other components.
• Pins: IN+, IN-, OUT+, OUT-

12V Power Supply

• Description: Provides the primary power source for the circuit.
• Pins: +, -

Wiring Details

Soil Moisture Sensor

• Positive: Connected to the Positive pin of the Soil Moisture Module.
• Negative: Connected to the Negative pin of the Soil Moisture Module.

Soil Moisture Module

• Positive: Connected to the Positive pin of the Soil Moisture Sensor.
• Negative: Connected to the Negative pin of the Soil Moisture Sensor.
• Analog: Connected to the A0 pin of the NodeMCU V3 ESP8266.
• Ground: Connected to the OUT- pin of the Buck Converter and the GND pin of the NodeMCU V3 ESP8266.
• VCC: Connected to the OUT+ pin of the Buck Converter and the Vin pin of the NodeMCU V3 ESP8266.

NodeMCU V3 ESP8266

• A0: Connected to the Analog pin of the Soil Moisture Module.
• GND: Connected to the Ground pin of the Soil Moisture Module and the OUT- pin of the Buck Converter.
• Vin: Connected to the VCC pin of the Soil Moisture Module and the OUT+ pin of the Buck Converter.

Buck Converter

• IN+: Connected to the + pin of the 12V Power Supply.
• IN-: Connected to the - pin of the 12V Power Supply.
• OUT+: Connected to the VCC pin of the Soil Moisture Module and the Vin pin of the NodeMCU V3 ESP8266.
• OUT-: Connected to the Ground pin of the Soil Moisture Module and the GND pin of the NodeMCU V3 ESP8266.

12V Power Supply

• +: Connected to the IN+ pin of the Buck Converter.
• -: Connected to the IN- pin of the Buck Converter.

Code Documentation

NodeMCU V3 ESP8266 Code

#define SOIL_PIN A0 // Analog pin connected to soil sensor

void setup() {
  Serial.begin(115200);
}

void loop() {
  int sensorValue = analogRead(SOIL_PIN); // Read analog value (0-1023)
  
  // Map the value to percentage (adjust range based on your sensor calibration)
  int moisturePercent = map(sensorValue, 1023, 0, 0, 100); 

  Serial.print("Soil Moisture: ");
  Serial.print(moisturePercent);
  Serial.println(" %");

  delay(1000); // Wait 1 second before the next reading
}

This code initializes the serial communication at a baud rate of 115200. In the loop function, it reads the analog value from the soil moisture sensor, maps it to a percentage, and prints the soil moisture percentage to the serial monitor every second.