Arduino - Display Temperature from LM35 Sensor on OLED

In this tutorial, we are going to learn how to read the temperature from LM35 sensor and display it on an OLED.

Arduino LM35 Temperature Sensor OLED W

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×SSD1306 I2C OLED Display 128x64
1×LM35 Temperature Sensor
1×Breadboard
4×Jumper Wires
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About OLED and LM35 Temperature Sensor

If you do not know about OLED and LM35 Temperature Sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino LM35 Temperature Sensor OLED Wiring Diagram

Image is developed using Fritzing. Click to enlarge image

Arduino Code - LM35 Temperature Sensor - OLED

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-display-temperature-from-lm35-sensor-on-oled */ #include <Wire.h> #include <Adafruit_GFX.h> #include <Adafruit_SSD1306.h> #define SCREEN_WIDTH 128 // OLED display width, in pixels #define SCREEN_HEIGHT 64 // OLED display height, in pixels #define ADC_VREF_mV 5000.0 // in millivolt #define ADC_RESOLUTION 1024.0 #define PIN_LM35 A0 // pin connected to LM35 temperature sensor Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C String tempString; 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 tempString.reserve(10); // to avoid fragmenting memory when using String } void loop() { // get the ADC value from the LM35 temperature sensor int adcVal = analogRead(PIN_LM35); // convert the ADC value to voltage in millivolt float milliVolt = adcVal * (ADC_VREF_mV / ADC_RESOLUTION); // convert the voltage to the temperature in Celsius float tempC = milliVolt / 10; tempString = String(tempC, 2); // two decimal places tempString += "°C"; Serial.println(tempString); // print the temperature in Celsius to Serial Monitor oledDisplayCenter(tempString); // display temperature 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, Go to Tools Manage Libraries
  • Arduino add library
  • 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
  • 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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