README.md

BMP280/BME280 sensor library for Arduino

This is a BMP280/BME280 temperature/pressure/humidity sensor library for Arduino.

Arduino library features

• Measurements:
  • BMP280: Temperature / pressure / approximate altitude
  • BME280: Temperature / pressure / approximate altitude / humidity
• Three operation modes:
  • Normal mode: Continues conversion
  • Forced mode: One-time conversion
  • Standby mode: Low-power, no conversion
• Sampling configuration
• Chip detect / read chip ID
• I2C interface only
• Small flash/RAM footprint

BMP280/BME280 sensor specifications

• Operating voltage: 1.71V .. 3.6V max
• Low current:
  • 1.8 uA @ 1 Hz humidity and temperature
  • 2.8 uA @ 1 Hz pressure and temperature
  • 3.6 uA @ 1 Hz humidity, pressure and temperature
  • 0.1 uA in sleep mode
• Operating range: -40...+85 °C, 0...100 % rel. humidity, 300...1100 hPa
• I2C bus interface: max 3.4 MHz
• No additional electronic components needed

Hardware

Connection Arduino board - BMX280 sensor

Pins board - BMX280	VCC	GND	SDA	SCL
Arduino UNO (ATMega328 boards)	5V	GND	A4	A5
Arduino Mega2560	5V	GND	D20	D21
Arduino Leonardo	5V	GND	D2	D3
Arduino DUE (ATSAM3X8E)	3V3	GND	20	21
ESP8266	3V3	GND	GPIO4 (D2)	GPIO5 (D1)
ESP32	3V3	GND	GPIO21	GPIO22

Other unlisted MCU's may work, but are not tested.

Examples

Examples | Erriez BMP280/BME280 sensor:

• ErriezBMX280

Documentation

• Doxygen online HTML
• Doxygen PDF
• BMP280 chip datasheet
• BME280 chip datasheet

Example

#include <Wire.h>
#include <ErriezBMX280.h>

// Adjust sea level for altitude calculation
#define SEA_LEVEL_PRESSURE_HPA      1026.25

// Create BMX280 object I2C address 0x76 or 0x77
ErriezBMX280 bmx280 = ErriezBMX280(0x76);


void setup()
{
    // Initialize serial
    delay(500);
    Serial.begin(115200);
    while (!Serial) {
        ;
    }
    Serial.println(F("\nErriez BMP280/BMX280 example"));

    // Initialize I2C bus
    Wire.begin();
    Wire.setClock(400000);

    // Initialize sensor
    while (!bmx280.begin()) {
        Serial.println(F("Error: Could not detect sensor"));
        delay(3000);
    }

    // Print sensor type
    Serial.print(F("\nSensor type: "));
    switch (bmx280.getChipID()) {
        case CHIP_ID_BMP280:
            Serial.println(F("BMP280\n"));
            break;
        case CHIP_ID_BME280:
            Serial.println(F("BME280\n"));
            break;
        default:
            Serial.println(F("Unknown\n"));
            break;
    }
}

void loop()
{
    Serial.print(F("Temperature: "));
    Serial.print(bmx280.readTemperature());
    Serial.println(" C");

    if (bmx280.getChipID() == CHIP_ID_BME280) {
        Serial.print(F("Humidity:    "));
        Serial.print(bmx280.readHumidity());
        Serial.println(" %");
    }

    Serial.print(F("Pressure:    "));
    Serial.print(bmx280.readPressure() / 100.0F);
    Serial.println(" hPa");

    Serial.print(F("Altitude:    "));
    Serial.print(bmx280.readAltitude(SEA_LEVEL_PRESSURE_HPA));
    Serial.println(" m");

    Serial.println();

    delay(1000);
}

Output

Erriez BMP280/BMX280 example

Sensor type: BME280

Temperature: 28.50 C
Humidity:    45.13 %
Pressure:    1024.88 hPa
Altitude:    11.27 m

Temperature: 28.55 C
Humidity:    45.21 %
Pressure:    1024.89 hPa
Altitude:    11.21 m

...

Set sampling

The sensor sampling and mode can be configured with function setSampling(). Recommended modes of operation according to the datasheet chapter "Recommended modes of operation":

// Set sampling
//
// Weather
//  - forced mode, 1 sample / minute
//  - pressure ×1, temperature ×1, humidity ×1
//  - filter off
//
// Humidity sensing
//  - forced mode, 1 sample / second
//  - pressure ×0, temperature ×1, humidity ×1
//  - filter off
//
// Indoor navigation
//  - normal mode, t standby = 0.5 ms
//  - pressure ×16, temperature ×2, humidity ×1
//  - filter coefficient 16
//
// Gaming
//  - forced mode, t standby = 0.5 ms
//  - pressure ×1, temperature ×1, humidity ×1
//  - filter off
bmx280.setSampling(BMX280_MODE_NORMAL,    // SLEEP, FORCED, NORMAL
                   BMX280_SAMPLING_X16,   // Temp:  NONE, X1, X2, X4, X8, X16
                   BMX280_SAMPLING_X16,   // Press: NONE, X1, X2, X4, X8, X16
                   BMX280_SAMPLING_X16,   // Hum:   NONE, X1, X2, X4, X8, X16 (BME280)
                   BMX280_FILTER_X16,     // OFF, X2, X4, X8, X16
                   BMX280_STANDBY_MS_500);// 0_5, 10, 20, 62_5, 125, 250, 500, 1000

Library dependencies

• Built-in Wire.h

Library installation

Please refer to the Wiki page.

Other Arduino Libraries and Sketches from Erriez

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