Arduino - DHT22 - OLED

In this tutorial, we are going to learn how to read the temperature and humidity from DHT22 module and display it on an OLED.

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×SSD1306 I2C OLED Display 128x64
1×DHT22 Module
1×Jumper Wires
1×(Optional) 9V Power Adapter for Arduino
1×(Recommended) Screw Terminal Block Shield for Arduino Uno
1×(Optional) Transparent Acrylic Enclosure For Arduino Uno

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.

About OLED display, DHT22 Temperature Humidity Sensor

If you do not know about OLED display, and DHT22 temperature humidity sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino DHT22 module OLED Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Arduino Code - DHT22 Sensor - OLED

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-dht22-oled */ #include <Wire.h> #include <Adafruit_GFX.h> #include <Adafruit_SSD1306.h> #include <DHT.h> #define SCREEN_WIDTH 128 // OLED display width, in pixels #define SCREEN_HEIGHT 64 // OLED display height, in pixels #define DHT22_PIN 2 // pin connected to DHT22 sensor Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C DHT dht22(DHT22_PIN, DHT22); String displayString; void setup() { Serial.begin(9600); // initialize OLED display with address 0x3C for 128x64 if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { Serial.println(F("SSD1306 allocation failed")); while (true); } delay(2000); // wait for initializing oled.clearDisplay(); // clear display oled.setTextSize(2); // text size oled.setTextColor(WHITE); // text color oled.setCursor(0, 10); // position to display dht22.begin(); // initialize DHT22 the temperature and humidity sensor displayString.reserve(10); // to avoid fragmenting memory when using String } void loop() { float humi = dht22.readHumidity(); // read humidity float tempC = dht22.readTemperature(); // read temperature // check if any reads failed if (isnan(humi) || isnan(tempC)) { displayString = "Failed"; } else { displayString = String(tempC, 1); // one decimal places displayString += "°C"; displayString += String(humi, 1); // one decimal places displayString += "%"; } Serial.println(displayString); // print the temperature in Celsius to Serial Monitor oledDisplayCenter(displayString); // display temperature and humidity on OLED } void oledDisplayCenter(String text) { int16_t x1; int16_t y1; uint16_t width; uint16_t height; oled.getTextBounds(text, 0, 0, &x1, &y1, &width, &height); // display on horizontal and vertical center oled.clearDisplay(); // clear display oled.setCursor((SCREEN_WIDTH - width) / 2, (SCREEN_HEIGHT - height) / 2); oled.println(text); // text to display oled.display(); }

Quick Steps

  • Open Arduino IDE on your PC.
  • Navigate to the Libraries icon on the left bar of the Arduino IDE.
  • Search “SSD1306”, then find the SSD1306 library by Adafruit
  • Click Install button to install the library.
Arduino OLED library
  • You will be asked for intalling some other library dependencies
  • Click Install All button to install all library dependencies.
Arduino Adafruit GFX sensor library
  • Search “DHT”, then find the DHT sensor library by Adafruit
  • Click Install button to install the library.
Arduino DHT sensor library
  • You will be asked for intalling some other library dependencies
  • Click Install All button all library dependencies.
Arduino Adafruit Unified sensor library
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
  • Put the sensor on hot and cold water, or grasp the sensor by your hand
  • See the result on OLED and Serial Monitor

※ NOTE THAT:

The about code automatically horizontal and vertical center aligns the text on OLED display

Video Tutorial

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