Circuit Documentation

Summary

The circuit in question is designed to monitor environmental conditions such as soil moisture, ambient light, temperature, and humidity. It utilizes an Arduino UNO as the central microcontroller to process sensor data and control peripherals like a relay module and an LCD display. The system is capable of reading soil moisture levels using a Soil Moisture Sensor, ambient light using an LDR module, and temperature and humidity using a DHT11 sensor. Based on the sensor readings, the Arduino can trigger relays to control external devices, and it displays the sensor data on an LCD screen with I2C communication.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• Used as the main controller for interfacing with sensors and modules

Soil Moisture Sensor

• Detects the moisture level in the soil
• Provides a digital or analog signal indicating moisture level

DHT11 Humidity and Temperature Sensor

• Measures ambient humidity and temperature
• Provides digital signal output with temperature and humidity data

Module LDR (Light-Dependent Resistor)

• Senses the level of ambient light
• Provides digital and analog outputs corresponding to light intensity

4 Channel Relay Module

• Allows the Arduino to control high power devices
• Contains four relays with Normally Open (N.O.) and Normally Closed (N.C.) contacts

LCD Screen 16x2 I2C

• Displays text on a 16x2 character screen
• Uses I2C communication for interfacing with the Arduino

Wiring Details

Arduino UNO

• 5V and GND pins provide power to all other components
• A0 connected to Soil Moisture Sensor signal pin
• A4 (SDA) and A5 (SCL) connected to LCD I2C pins
• D2 connected to DHT11 data pin
• D3 connected to LDR digital output pin
• D5, D6, D7 connected to relay module input pins IN 1, IN 2, IN 3 respectively

Soil Moisture Sensor

• VCC connected to Arduino 5V
• GND connected to Arduino GND
• SIG connected to Arduino A0

DHT11 Humidity and Temperature Sensor

• VDD connected to Arduino 5V
• DATA connected to Arduino D2
• GND connected to Arduino GND

Module LDR

• VCC connected to Arduino 5V
• GND connected to Arduino GND
• DO connected to Arduino D3

4 Channel Relay Module

• VCC+ connected to Arduino 5V
• VCC- (GND) connected to Arduino GND
• IN 1, IN 2, IN 3 connected to Arduino D5, D6, D7 respectively

LCD Screen 16x2 I2C

• SCL connected to Arduino A5
• SDA connected to Arduino A4
• VCC connected to Arduino 5V
• GND connected to Arduino GND

Documented Code

#include<LiquidCrystal_I2C.h>
#include "DHT.h"
#define DHTPIN 2 
#define DHTTYPE DHT11 

int a;
int ldr= 3;
int moist_sensor = A0 ;
int relaymoist = 5 ;
int relaydht = 6;
int relayldr = 7; 

DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27,16,2);

void setup()
{
  pinMode(5,OUTPUT);
  pinMode(6,OUTPUT);
  pinMode(7,OUTPUT);
  Serial.begin(9600);
  dht.begin();
  lcd.begin(16,2);
  lcd.backlight();
  lcd.setBacklight(HIGH);
  lcd.setCursor(0,0);
  lcd.print("Water");
  lcd.setCursor(6,0);
  lcd.print("Temp");
  lcd.setCursor(11,0);
  lcd.print("Humid");
}

void loop()
{
  delay(500);
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  int intensity = digitalRead(ldr);
  int moisture = analogRead(moist_sensor);

  lcd.setCursor(6,1);
  lcd.print(t);
  lcd.setCursor(12,1);
  lcd.print(h);

  if (intensity == LOW){
    digitalWrite(relayldr,HIGH);
  }
  else if(intensity == HIGH ){
    digitalWrite(relayldr,LOW);
  }
  if(t>=30){
    digitalWrite(relaydht,LOW);
  }
  else if(t<30){
    digitalWrite(relaydht,HIGH);
  }
  
  if (moisture>=900)
  {
    digitalWrite(relaymoist, LOW );
    lcd.setCursor(2,1);
    lcd.print("1 ");
    Serial.print("1 ");

  }
  
  else if(moisture>=850 && moisture<900)
  {
    digitalWrite(relaymoist, LOW );
    lcd.setCursor(2,1);
    lcd.print("2 ");
    Serial.print("2 ");

  }
  else if(moisture>=800 && moisture<850)
  {
    digitalWrite(relaymoist, LOW );
    lcd.setCursor(2,1);
    lcd.print("3 ");
    Serial.print("3 ");


  }
  else if(moisture>=750 && moisture<800)
  {
    digitalWrite(relaymoist, LOW );
    lcd.setCursor(2,1);
    lcd.print("4 ");
    Serial.print("4");

  }
  else if(moisture>=700 && moisture<750)
  {
    digitalWrite(relaymoist, LOW );
    lcd.setCursor(2,1);
    lcd.print("5 ");
    Serial.print("5");

  }
  else if(moisture>=650 && moisture<700)
  {
    digitalWrite(relaymoist, LOW );
    lcd.setCursor(2,1);
    lcd.print("6 ");
    Serial.print("6");

  }
  else if(moisture>=550 && moisture<650)
  {
    digitalWrite(relaymoist, HIGH );
    lcd.setCursor(2,1);
    lcd.print("7 ");
    Serial.print("7");

  }
  else if(moisture>=500 && moisture<550)
  {
    digitalWrite(relaymoist, HIGH );
    lcd.setCursor(2,1);
    lcd.print("8 ");
    Serial.print("8");

  }
  else if(moisture>=450 && moisture<500)
  {
    digitalWrite(relaymoist, HIGH );
    lcd.setCursor(2,1);
    lcd.print("9 ");
    Serial.print("9");

  }
  else if(moisture>=400 && moisture<450)
  {
    digitalWrite(relaymoist, HIGH );
    lcd.setCursor(2,1);
    lcd.print("10");
    Serial.print("10");

  }
  
  Serial.print("|");
  Serial.print(t);
  Serial.print("C");
  Serial.print("|");
  Serial.print(h);
  Serial.print("%");
  Serial.println("|");
}

This code is responsible for initializing the sensors and LCD, reading sensor data, and controlling the relay module based on the sensor inputs. It also displays the moisture level, temperature, and humidity on the LCD screen and outputs the data to the serial monitor.