How to Create Digital Room Thermometer Using Arduino UNO R3

Introduction

Nowadays, all air-conditioning systems contain temperature management systems to maintain a constant temperature inside the room. This system measures the temperature with the help of a temperature sensor. This sensor works like a thermometer.

In this article, you will learn about how to create a digital thermometer using the Arduino microcontroller board.

Prerequisites for developing this system

Hardware requirements

Hardwares	Nos
Arduino UNO	1
DHT11 Temperature sensor	1
10k ohm potentiometer	1
10k ohm Resistor	1
LCD crystal display	1
220-ohm resistor	1
Breadboard	-
Connecting wires	-

Software requirements

Arduino IDE (For uploading code to Arduino Microcontroller)

In this experiment, we can do three stages of work for creating Digital Room Thermometer:

1. Connect all hardware

2. Write & upload code to Arduino board

3. Test our developed system

Stage 1 [Connecting all hardware’s]

Step 1

First, we can connect the LCD crystal display with the Arduino UNO board using Jumper wires. I am using a breadboard to extend power terminals for making this system.

Refer to the below LCD crystal Pin diagram for making an easy connection with Arduino

Place a 10K ohm potentiometer near the LCD crystal display. It can adjust the contrast of the LCD screen and create a power connection from Arduino +5V and GND right and left end of the potentiometer. Make a connection from the center terminal of the potentiometer to VEE (contrast control) LCD crystal display. (Refer to the connection diagram)

Pin Configuration

Arduino Breadboard LCD Crystal Display

Pin 3 ---------------------------------------------------------------------------> Data pin 4

Pin 4 ---------------------------------------------------------------------------> Data pin 5

Pin 5 ---------------------------------------------------------------------------> Data pin 6

Pin 6 ----------------------------------------------------------------------------> Data pin 7

Pin 8 ----------------------------------------------------------------------------> Register select

Pin 7 ----------------------------------------------------------------------------> Enable

+ 5V -----------------> Potentiometer Right Terminal-------------------->Potentiometer Centre terminal ----> VEE (Contrast Control) LCD crystal

+5V ---------------------------> 220-ohm Resistor -------------------------> LED +5V pin [LCD Crystal]

GND ------------------------------------------------------------------------------->Potentiometer Left terminal, Ground pin & LED - Ground pin [Connect to both pin]

Step 2

Next, DHT11 Temperature sensor to Arduino board as per below pin Configuration.

Pin Configuration

DHT11 temperature sensor Arduino

VCC ----------------------------------------------------------------> +5V

DATA <------------------------- 10 K ohm ---------------------- +5V

DATA --------------------------------------------------------------> Pin2

GND ----------------------------------------------------------------> GND

Stage 2 [Write & upload code to Arduino]

In this step, write code for Arduino using the Arduino IDE.

Download Arduino software using this link here.
Install and open an Arduino IDE in your PC/Laptop
Connect your Arduino board to your computer using a USB data cable
Copy and paste below the code into the Arduino IDE
1. #include "LiquidCrystal.h"
2. #define DHTPIN 2
3. #define DHTTYPE DHT11
4. #define LCD_PIN_RS 8
5. #define LCD_PIN_E 7
6. #define LCD_PIN_DB4 3
7. #define LCD_PIN_DB5 4
8. #define LCD_PIN_DB6 5
9. #define LCD_PIN_DB7 6
10. LiquidCrystal lcd(LCD_PIN_RS,LCD_PIN_E,LCD_PIN_DB4,LCD_PIN_DB5,LCD_PIN_DB6,LCD_PIN_DB7);
11. #include "DHT.h"
12. DHT dht(DHTPIN, DHTTYPE);
14. void setup() {
15. Serial.begin(9600);
16. dht.begin();
17. lcd.begin(16, 2);
18. lcd.print("C#corner");
19. lcd.setCursor(0,1);
20. lcd.print("Humid Temp Sys");
21. delay(2000);
22. }
24. void loop() {
25. delay(2000);
26. float h = dht.readHumidity();
27. float t = dht.readTemperature();
28. float f = dht.readTemperature(true);
29. if (isnan(h) || isnan(t) || isnan(f)) {
30. lcd.print(F("Failed to read from DHT sensor!"));
31. return;
32. }
33. lcd.clear();
34. lcd.setCursor(0,0);
35. lcd.print("Temp: ");
36. lcd.print(t);
37. lcd.print(F(" °C "));
38. }

Save and upload this code to the Arduino UNO board. After Code upload is completed, our digital thermometer starts to read the temperature :).

Stage 3 [Test our developed system]

Our developed digital thermometer using Arduino is working perfectly. Now, this digital thermometer displays a normal room temperature.

Next, I am placing a DHT11 temperature sensor near the laptop cooling vent, and the temperature has drastically increased.

Conclusion

In this article, we studied how to create a digital room thermometer using Arduino UNO R3.