Tutorial: Digital Termometer with Arduino and 16x2 LCD Display

This tutorial shows an interesting way to read the temperature from the environment with the Arduino, and shows it on a LCD 16x2 display (in Fahrenheit), by using some elements from its programming and the temperature LM35DZ sensor.

For that, it will be necessary the following components:

- 1 Arduino board

- 1 LCD 16x2 display

- 1 10K potentiometer

- 1 Temperature LM35 sensor

- Jumpers for connection

This sensor captures the external temperature and converts it into a corresponding voltage value. In this circuit, we connect the output Vo of the sensor to the Arduino’s A0 pin, which converts it to a float value of temperature, and then, exhibits it on the LCD. The 10K potentiometer adjusts the contrast of the display.

 

Now, set up the circuit below with the Arduino and the other components:  

And then, open the Arduino’s IDE and enter the following code:

 

#include  <LiquidCrystal.h>         // Include the library to use a LCD display

#define          sensor           0        // Define the A0 pin as “sensor”

 

int  Vin;           //  Variable to read the value from the Arduino’s pin

float  Temperature; //  Variable that receives the converted voltage value to temperature

float     TF; // Variable to receive the converted value from  ºC to ºF

 

LiquidCrystal  lcd    (12, 11, 5, 4, 3, 2); 

/* The function above declares which Arduino’s pins will be used for controlling the LCD */

void  setup()

{

  lcd.begin(16, 2);                            //  It tells the Arduino that the display is a 16x2 type

  lcd.print("Temperature: ");           //  Send the text to the screen of the display.

}

void  loop()

{

  Vin = analogRead (sensor);  /*   Tells the Arduino to read the pin and stores the value in “Vin” */

  Temperature=(500*Vin)/1023;  /* Converts the voltage value into temperature and stores it into the “Temperature”  variable  (in  ºC)*/

TF = ((9*Temperature)/5)+32; // Converts  ºC to ºF

  lcd.setCursor(0, 1);           // Moves  the cursor of the display to the next line

  lcd.print(TF);    // Exhibits the value of the temperature on the display

  lcd.print(" F");         // Writes “F” to indicate that it is in Fahrenheit scale.

 

  delay(1000);  //  Waits for a second to read the pin again

}

In the end, upload the code to your Aduino.

Your project to show the temperature is ready!!! We hope you have enjoyed. Any doubts, post here.

Note: The LM35DZ sensor converts temperature values from -55ºC to 150ºC.

If somebody is interested, this is the explanation for the conversion calculation from voltage to temperature done by the software.

In this sensor, for each 1ºC received, the Vo output is added in 10mV, in a range from 0 to 5V, with 10 bits of resolution for Analog/Digital conversion (1024 different values to represent the temperature).

Thus, the maximum value (1023, therefore it is from 0 to 1023) will be 5V. The half will match 511 or 2.5V, and so forth. For calculation purposes, there would be 5V in the output of the sensor for a temaprature value of 500ºC (which is different in a real situation). However, this regard lets us generalize it to the following relation:

Temperature  ----- Vin

         500ºC  ----- 1023              (maximum values)

 

So, there will be:

Temperature = (500*Vin)/1023, but as it is in ºC and we want in ºF, we convert it:

TF = ((9*Temperature)/5)+32, and this is the printed value on the LCD display.

 

See you next time!!!

 

Reference links:

- arduino.cc/en/Tutorial/LiquidCrystal

- "LM 35" datasheet

Views: 18337

Tags: 16x2, LCD, LM35, display, environment, sensor, temperature

Comment by HaimaN Adel on January 26, 2013 at 8:42am

thank you

Comment by Roman Piątkowski on July 18, 2013 at 6:18am

There's n error in your code.

Must change  Temperature=(500*Vin)/1023 to  Temperature=(500.0*Vin)/1023.0 becouse temperature over ~30 makes minus values on lcd (Vin*500 is over limit of 32k) 

Comment by Angelo Palloni on August 23, 2013 at 10:10am

I love this setup.

Comment by Angelo Palloni on August 23, 2013 at 10:11am

it worked perfect for me, first time.

Comment

You need to be a member of GarageLab (arduino, electronics, robotics, hacking) to add comments!

Join GarageLab (arduino, electronics, robotics, hacking)

Latest Activity

GarageLab posted blog posts
8 hours ago
Profile Iconleon crist, Tim Owen and Mishca de Costa joined GarageLab (arduino, electronics, robotics, hacking)
Monday
GarageLab posted a blog post

Arduino-Powered Turntables That Turn DJing Into Child’s Play

Per Holmquist has always had a finely tuned ear for music. “When I hear a song for the first time I…See More
Monday
GarageLab posted a blog post
Friday
Jean-Guillaume LALANNE posted a discussion

Smallest Arduino with BLE stack and push button integrated

Hi,I am a newbie in the maker world. I have bought a RFDUINO some month ago to play with.I did find…See More
Friday
Profile IconDavid bolles and Abhisht Yadav joined GarageLab (arduino, electronics, robotics, hacking)
Sep 11
GarageLab posted blog posts
Sep 11
chuby okafor updated their profile
Sep 10
maurice patrick commented on GarageLab's blog post 3D printer uses Arduino controller and makes food in unusual ways
"Sweet!!!!"
Sep 10
Stephen Wizowski left a comment for Stephen Wizowski
"NO... do not like this approach... AT ALL!"
Sep 10
Profile IconBernie Whalen, FRANK KWABENA, mikedaniels and 11 more joined GarageLab (arduino, electronics, robotics, hacking)
Sep 10
GarageLab posted a blog post

This Robot Crawls Through Acid, Ice and Fire

This robot, developed at Professor George M. Whitesides’ lab at Harvard University has recently…See More
Sep 10
GarageLab posted a blog post
Sep 8
Antonio Turner posted a status
Sep 8
GarageLab posted blog posts
Sep 5
Profile IconWilliam Ritchie, Chuck Untulis, David Perez and 3 more joined GarageLab (arduino, electronics, robotics, hacking)
Sep 5
GarageLab posted blog posts
Sep 3
GarageLab posted blog posts
Sep 2
Joonas Karjalainen is now a member of GarageLab (arduino, electronics, robotics, hacking)
Sep 2
Veritus posted photos
Sep 1

© 2014   Created by Marcelo Rodrigues.

Badges  |  Report an Issue  |  Terms of Service