Bme280 - Measuring temperature, pressure and humidity (examples)

This page contains some simple examples with function documentation on how to take measurements using the BME280 temperature, pressure, and humidity sensor.

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Connections for this example

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Initialization

To use the BME280 sensor, first include the required library, create the sensor object, and initialize the sensor in the setup() function.

//Include the library
#include <BME280-SOLDERED.h>

//Create an instance of the sensor
BME280 bme280;

void setup() {
  //Initialize an I2C connection with the sensor
  bme280.begin();
}
//...

bme280.begin()

Initializes the BME280 sensor, setting up communication over I2C and setting oversampling value to each sensor

Returns value: None

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Getting measurements

All values

To get the values for all measurements (temperature, humidity, and pressure), use the readSensorData() function. The sensor gets the reading values, stores them in the addresses of the function arguments, and scales the values into the appropriate form.

void loop()
{
  float temperature, humidity, pressure;
  //Store the sensor data into the variables
  bme280.readSensorData(temperature, humidity, pressure); 
  //Print all the values onto the screen
  Serial.println(
    "Temperature: " + String(temperature) + "C\n" +
    "Humidity: " + String(humidity) + "%\n" +
    "Pressure: " + String(pressure) + "hPa"
  );
  delay(1000); //1 second delay between measurements
}

Serial monitor

bme280.readSensorData(float &temp, float &humidity, float &pressure)

Gets the reading values, stores them in the addresses of the function arguments, and scales the values into the appropriate form.

Returns value: None

Function parameters:

Type	Name	Description
float	temp	Variable in which the temperature value will be stored
float	humidity	Variable in which the humidity value will be stored
float	pressure	Variable in which the pressure value will be stored

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Temperature

To get temperature values only, use the readTemperature() function. The sensor samples the temperature in degrees Celsius.

void loop()
{
  float temperature;
  //Store the sensor data into the variable
  temperature = bme280.readTemperature();
  //Print the value onto the screen
  Serial.println("Temperature: " + String(temperature) + "C \n");
  delay(1000); //1 second delay between measurements
}

⚠️

Because the sensor by itself generates heat, a temperature offset may be needed. Make an independent temperature reading and add an offset if needed:

void loop()
{
  float temperature;
  float offset = 2.5; // If needed, add an offset
  //Store the sensor data into the variable
  temperature = bme280.readTemperature();
  temperature += offset; // Add the offset to the temperature
  //Print the value onto the screen
  Serial.println("Temperature: " + String(temperature) + "C \n");
  delay(1000); //1 second delay between measurements
}

Serial monitor

bme280.readTemperature()

Reads the values from the sensor and returns the scaled Celsius value

Returns value: Float value of the temperature reading in degrees Celsius

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Pressure

To get pressure values only, use the readPressure() function. The sensor samples the pressure in hPa.

void loop()
{
  float pressure;
  //Store the sensor data into the variable
  pressure = bme280.readPressure();
  //Print the value onto the screen
  Serial.println("Pressure: " + String(pressure) + "hPa \n");
  delay(1000); //1 second delay between measurements
}

Serial monitor

bme280.readPressure()

Reads the value from the sensor and returns the scaled hPa value

Returns value: Float value of the pressure reading in hPa

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Humidity

To get humidity values only, use the readHumidity() function. The sensor samples humidity as a percentage.

void loop()
{
  float humidity;
  //Store the sensor data into the variable
  humidity = bme280.readHumidity();
  //Print the value onto the screen
  Serial.println("Humidity: " + String(humidity) + "% \n");
  delay(1000); //1 second delay between measurements
}

Serial monitor

bme280.readHumidity()

Reads the value from the sensor and returns the scaled percentage value

Returns value: Float value of the humidity reading in %

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Altitude

Based on sensor reading

The altitude value can be calculated by using the readAltitude() function. The value is calculated based on the pressure reading and the sea level.

void loop()
{
  float altitude;
  //Store the sensor data into the variable
  altitude = bme280.readAltitude();
  //Print the value onto the screen
  Serial.println("Altitude: " + String(altitude) + "m \n");
  delay(1000); //1 second delay between measurements
}

Serial monitor

bme280.readAltitude()

Calculates the altitude by taking the pressure reading

Returns value: Float value of altitude in meters

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Based on given pressure value

void loop()
{
  float altitude, pressure;
  //First, get a pressure reading
  pressure = bme280.readPressure();
  //Store the calculated result into the variable
  altitude = bme280.calculateAltitude(pressure);
  //Print the value onto the screen
  Serial.println("Altitude: " + String(altitude) + "m \n");
  delay(1000); //1 second delay between measurements
}

bme280.calculateAltitude(float pressure)

Calculates the altitude by the given pressure value in the argument

Returns value: Float value of altitude in meters

Function parameters:

Type	Name	Description
float	pressure	Pressure value in hPa