r4lph127
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Temperature and Humidity sensor with LED Lights

This project project the temperature and the humidity level and turn on the LED Light depending on the temperature.

BeginnerFull instructions provided1,166
Temperature and Humidity sensor with LED Lights

Things used in this project

Hardware components

Arduino Mega 2560 & Genuino Mega 2560
Arduino Mega 2560 & Genuino Mega 2560
×1
LED (generic)
LED (generic)
×3
DHT11 Temperature & Humidity Sensor (3 pins)
DHT11 Temperature & Humidity Sensor (3 pins)
×1
Jumper wires (generic)
Jumper wires (generic)
×30
Alphanumeric LCD, 16 x 2
Alphanumeric LCD, 16 x 2
×1
Resistor 330 ohm
Resistor 330 ohm
×3
Breadboard (generic)
Breadboard (generic)
×1

Software apps and online services

Arduino IDE
Arduino IDE

Story

Read more

Schematics

DHT11 with LCD and LED Light

Code

DHT11 Sensor used with LCD Display and LED Lights.

Arduino
/* Created by Ralph Nader on 1/10/19.
   Copyright  2019 Ralph Nader. All rights reserved.
   Made with  for everyone.
   Spread your knowledge.
   If you have any error or question, email me at "ralph@driple.co".
*/
#include <LiquidCrystal.h>             // Include the LiquidCrystal library.
#include "DHT.h"                       // Include the DHT library.

#define DHTPIN 8                       // Set the DHT Pin.
#define DHTTYPE DHT11                  // Set the DHT type.

LiquidCrystal lcd(1, 2, 4, 5, 6, 7);   // Creates a LiquidCrystal object. Parameters: (RS, Enable (E), d4, d5, d6, d7).
DHT dht(DHTPIN, DHTTYPE);              // Creates a DHT object. Parameters: (DHT Pin, DHT Type).

const int yellowLED = 9;               // Adds a led light (in that case, it is yellow) to pin 9.
const int blueLED = 10;                // Adds a led light (in that case, it is blue) to pin 10.
const int whiteLED = 11;               // Adds a led light (in that case, it is white) to pin 11.

void setup() {
  lcd.begin(16, 2);                    // Initializes the interface to the LCD screen, and specifies the dimensions (width and height) of the display.
  lcd.setCursor(0, 0);                 // Set the cursor to column 0, line 0.
  pinMode(blueLED, OUTPUT);            // Change to output the blue pin.
  pinMode(yellowLED, OUTPUT);          // Change to output the yellow pin.
  pinMode(whiteLED, OUTPUT);           // Change to output the white pin.

  dht.begin();                         // Launch the DHT11 sensor.
  digitalWrite(blueLED,LOW);           // Turn off LED.
  digitalWrite(yellowLED,LOW);         // Turn off LED.
  digitalWrite(whiteLED, LOW);         // Turn off LED.

  lcd.print("Temperature:");           // Print "Temperature:" on LCD Screen.
  
  lcd.setCursor(0, 1);                 // Set the cursor to column 0, line 1.
  lcd.print("Humidity   :");           // Print "Humidity:" on LCD Screen.
}

void loop() {
  delay(500);                         // Wait 0.5 seconds before updating the values.
  float T = dht.readTemperature();    // Read temperature in Celsius. If you want the Temperature in Fahrenheit, simply add "true" between the parentheses ==> float T = dht.readTemperature(True);
  float H = dht.readHumidity();       // Read humidity in percentage.

  if (isnan(H) && isnan(T)) {         // See if H (the Humidity variable) is NaN (Not A Number) && (Logical AND) See if T (the Temperature variable) is NaN to show error. 
    lcd.print("ERROR");               // Print error where there's the error.
    return;                           // Repeat the process with each update (each second).
  }

  if(T>22){                           // See if the temperature is bigger than 22C.
    digitalWrite(yellowLED, HIGH);    // The yellow led will turn on.
    digitalWrite(blueLED, LOW);       // The blue led will turn off.
    digitalWrite(whiteLED, LOW);      // The white led will turn off.s
    
  }
  else if(T<22){                      // If the temperature is smaller than 22C.
    digitalWrite(blueLED, HIGH);      // The blue led will turn on.
    digitalWrite(yellowLED, LOW);     // The yellow led will turn off.
    digitalWrite(whiteLED, LOW);      // The white led will turn off.
  }

  else if(T=22){                      // If the temperature is equal than 22C.
    digitalWrite(whiteLED, HIGH);     // The white led will turn on.
    digitalWrite(yellowLED, LOW);     // The yellow led will turn off.
    digitalWrite(blueLED, LOW);       // The blue led will turn off.
  }

  lcd.setCursor(12, 0);               // Set the cursor to column 12, line 0.
  lcd.print(T);                       // Print the temperature.
  lcd.setCursor(12, 1);               // Set the cursor to column 12, line 1.
  lcd.print(H);                       // Print the humidity level.
}

Credits

r4lph127

r4lph127

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