Arduino with temperature sensor – Interfacing LCD and LM35

Let’s see how to interface Arduino with temperature sensor. LM35 is a three-terminal temperature sensing device. It is used to measure temperature in the range of -55°C to 150°C. It is a three-terminal device that produces an analog voltage proportional to the temperature of its surroundings. We can convert the analog output into digital using ADC. The sensitivity of LM35 is 10mV/degree Celsius it does not require any extra calibration (e.g. 300mV means 30℃). Its output is very precise. Supply voltage ranges from 4V to 30V.

Circuit Diagram of Arduino with temperature sensor:

Components Required:

Circuit connections:

The LM35 temperature sensor is powered by an Arduino board via VCC & GND pins.

The analog output pin of the LM35 temperature sensor is connected to the analog input pin A0 of Arduino.

10 K Ohm potentiometer controls the brightness of the panel.

The second pin is connected to pin 3 of the LCD.

First pin of potentiometer connected to + VCC.

Third pin of potentiometer connected to GND.

RS pin of LCD connects to digital pin 12 of Arduino UNO.

Pin E (Enable) connected to digital pin 11.

Pin D4 connects to pin number 5.

D5 pin connects to digital pin 4 of Arduino.

Pin D6 connects to digital pin 3.

Pin D7 connects to digital pin 2 of Arduino UNO.

R / W pin connected to the GND.

Pin 1 and pin 4 are connected to GND.

Pin 2 connected to + VCC.

The first and third pins of the potentiometer can be interchanged.

Working of Temperature sensor with code:

#include <LiquidCrystal.h>
float temp;
int sensor = A0;
float tempc;
float tempf;

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

The instance of the LiquidCrystal lcd shows LCD pins connected to the Arduino digital outputs.

void setup () {
// set the number of columns and the number of lines of lcd
lcd.begin (16, 2);
}

void loop () {
temp=analogRead(sensor);

Read analog voltage from sensor and store it in a temporary float variable.

tempc=(temp*4.88)/10;

This line converts float value into °C.

tempf=(tempc*1.8)+32;

This line converts °C into Fahrenheit.

lcd.setCursor(0,0);
lcd.print("Temp in C = ");
lcd.println(tempc);

These two lines print Temperature value in °C.
lcd.setCursor(0,1);
lcd.print("Temp in F = ");
lcd.println(tempf);

Above two lines print value in Fahrenheit
}

Arduino with temperature sensor Final Output:

#include <LiquidCrystal.h>
int sensor = A0;
float temp;
float tempc;
float tempf;

LiquidCrystal lcd (12, 11, 5, 4, 3, 2);
void setup () {
lcd.begin (16, 2);
}

void loop () {
temp=analogRead(sensor);
tempc=(temp*4.88)/10;
tempf=(tempc*1.8)+32;
lcd.setCursor(0,0);
lcd.print("Temp in C = ");
lcd.println(tempc);
lcd.setCursor(0,1);
lcd.print("Temp in F = ");
lcd.println(tempf);
}

Here is the TinkerCAD Simulation of This project:

Conclusion:

• The above circuit is used to monitor the temperature in many places,
• In weather monitoring system.
• In farming fields
• Industrial places
• At home and anywhere there is a need for temperature data.