Digital Thermometer using LCD and Arduino

Updated: Feb 19

In this project, you will learn to make a #digitalthermometer using Arduino and LCD.

Hardware Components - Digital Thermometer using LCD and Arduino |

1. Arduino Uno:

It is an open-source microcontroller board that can be programmed according to user requirements. Arduino Uno board is used for interfacing the input-output elements to construct a project.

Arduino Uno Board

2. Breadboard:

A breadboard is a simple rectangular board that has many holes shorted in a specific manner. It is the construction base for implementing electronic projects. The holes are used to connect circuit components like ICs, capacitors, potentiometers.

How to use a breadboard?

Breadboard

3. LCD Monitor:

Liquid Crystal Display is an electronically modulated display used to produce images in monochrome.

LCD Display

4. TMP36 Temperature sensor:

It is an analog temperature sensor with a wide temperature range. The left pin is for voltage input (2.7V to 5.5V) and, the pin on the right side is for the ground. The pin in the center is for the analog output.

TMP36 Temperature Sensor

5. Resistor- 220Ω:

The resistor is a passive electronic component that offers resistance to the current flowing through it. Here it is used to reduce the current flowing through the LCD. A 220Ω resistor is used in this project.

220Ω Resistor

6. Potentiometer:

A potentiometer is a three-terminal device that acts as a variable resistor or a rheostat. One of the terminals has an adjustable contact that is used to set the resistance value. It is used to tune the circuit to get the desired output.

Potentiometer

7. Jumper wires:

Jumper wires have connectors and pins that are used to connect different components on a breadboard.

Jump Wires

Circuit Connections:

Digital Thermometer using LCD and Arduino-Circuit diagram

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The first pin in the LCD is the ground pin and is connected to the ground of the Arduino.
The second pin in the LCD is the VCC pin which is connected to the 5V of the Arduino.
V0 of the LCD to the wiper contact (2nd pin) of the potentiometer.
Terminal 1 of the potentiometer is connected to the 5V and terminal 2 to the ground pin.
Register select (RS) of the LCD to the D12 of the Arduino.
RW(Read /Write) of the LCD to the ground.
E (Enable) pin of the LCD to D11 of the Arduino.
DB4 of the LCD to D5 of the Arduino.
DB5 of the LCD to D4 of the Arduino.
DB6 of the to D3 of the Arduino.
DB7 of the LCD to D2 of the Arduino.
LED anode pin of the LCD to a 220Ω resistor which in turn is connected to the 5V power supply of the Arduino.
LED cathode pin of the LCD to ground.
Power pin of the TMP36 temperature sensor to the 5V of the Arduino; Ground pin of the TMP36 to the ground of the Arduino.
Vout of the TMP36 to the A0 of the Arduino.

Code - Digital Thermometer using LCD and Arduino

Digital Thermometer using LCD and Arduino-Project code

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Liquidcrystal Library is included in the code and the LCD pins that are used are declared.
The variables used in the code are declared.
In the loop, the analog values from the sensor are assigned to "degree". It is divided by 1024 and is assigned to the "realdegree" variable.
This value will range from 0 to 1, hence it is multiplied by 5 to increase the range.
To get the actual temperature the realdegree value is multiplied by 100.
The cursor is set to the second line of the LCD.
Then, the degree Celsius value is converted to the Fahrenheit scale.
The Fahrenheit value is displayed as the output on the LCD.

Working:

The TMP36 temperature sensor works like a diode, i.e. the temperature changes with the change in the voltage at a defined rate. Here, the sensor reading is displayed in the LCD monitor using #Arduino.

Design the above circuit in the TinkerCad, type the code and simulate the circuit.

Vary the potentiometer and set it to the appropriate value. Then vary the temperature sensor to get the temperature values in Fahrenheit on the LCD screen.

Check the Project Working video here - HOW TO INTERFACE TEMPERATURE SENSOR AND LCD WITH ARDUINO: Digital Thermometer using LCD and Arduino

Written by-

Name- Nagashree R Nadig

Portfolio Link- https://www.learnelectronicsindia.com/team/nagashree-r-nadig