Lesson 27: Using DHT11 Temperature Sensor with LCD Screen | Arduino Step by Step Course
Related or required files and link to this lesson
- DHT11 Library from Robojax.com (zip)
- LCD Library from Robojax.com (zip)
- DHT11 Library on GetHub
- DHT11 Manual(pdf)
Part 3: LCD, LED and OLED Screens
In this lecture we learn how to use DHT11 to measure the temperature and display it on LCD1602 or LCD2004 LCD screen.
/*
* Robojax Arduino Step By Step Course
* Lesson 26 DHT11 with LCD1602-I2C display
* This is the Arduino code for DHT11 module to read temprature and humidity
* This code can display temprature in:
* C is used to get Celsius
* F is used to get fahrenheit
* K is used for Kelvin
* *
* Written by Ahmad Shamshiri for Robojax
* on Jan 04, 2018
* Robojax.com
Please watch video instruction here https://youtu.be/0XMLnCYkvbE
This code is available at http://robojax.com/course1/?vid=lecture11
with over 100 lectures Free On YouTube Watch it here http://robojax.com/L/?id=338
Get the code for the course: http://robojax.com/L/?id=339
* This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.*
* This code has been download from Robojax.com
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
// header file from GetHub: https://github.com/adidax/dht11
#include <dht11.h>
dht11 DHT11; // create object of DHT11
#define dhtpin 2 // set the pin to connect to DHT11
// start of settings for LCD1602-I2C
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
// Set the LCD address to 0x3F for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x3F, 16, 2);
// end of settings for LCD1602-I2C
void setup() {
Serial.begin(9600);// setting up serial monitor
// initialize the LCD,
lcd.begin();
// Turn on the blacklight and print a message.
lcd.backlight();
lcd.clear();
lcd.setCursor (0,0); //
lcd.print("DHT11 Sensor");
delay(2000);
}
void loop() {
//Robojax Step By Step Arduono Course YouTube Watch it here http://robojax.com/L/?id=338
DHT11.read(dhtpin);// initialize the reading
int humidity = DHT11.humidity;// get humidity
lcd.clear();// clearn previous values from screen
lcd.setCursor (0,0); //character zero, line 1
lcd.print("LCD1602 DHT11"); // print text
// print distance in degrees C
lcd.setCursor (0,1); //character 0, line 2
lcd.print(getTemp('C'));// print Temperature Celsius
lcd.setCursor (4,1); //character 5, line 2
lcd.print((char)223);// print degree
lcd.setCursor (5,1); //character 6, line 2
lcd.print("C");// print C
// print distance degrees F
lcd.setCursor (7,1); //character 8, line 2
lcd.print(getTemp('F'));// print distance in cm
lcd.setCursor (13,1); //character 14, line 2
lcd.print((char)223);// print degree
lcd.setCursor (14,1); //character 16, line 2
lcd.print("F");// print F
//code for Robojax.com video
Serial.print(getTemp('C'));
Serial.print("C ");
Serial.print(getTemp('F'));
Serial.print("F ");
Serial.print(getTemp('K'));
Serial.print("K ");
Serial.print(" humidity:");
Serial.print (humidity);
Serial.print("% ");
Serial.println();
delay(500);
}
/*
* getTemp(char type)
* type character of upper case
* C is used to get Celsius
* F is used to get fahrenheit
* K is used for Kelvin
*/
float getTemp(char type) {
//Robojax Step By Step Arduono Course YouTube Watch it here http://robojax.com/L/?id=338
float temp = (float)DHT11.temperature;//get temp
if(type =='F')
{
return temp * 1.8 + 32;// convert to fahrenheit
}else if(type =='K')
{
return temp + 274.15;// convert to Kelvin
}else{
return temp;
}
}