This is the BME280_LITE library, designed to be lightweight for memory. This library supports I2C communication only.

This function writes the registers in the BME280 responsible for the initialization of the sensor, and must be called once in setup(). The registers configured are:

• CTRL_HUM (humidity control)
• CTRL_MEAS (measure control)
• CONFIG (configuration)

The initialization function configures some settings like:

• Oversampling: Controls how many times a measurement is taken and averaged for the final result
• Mode:
  • forced - runs once
  • forced 2 - runs twice
  • sleep - sensor sleeps
  • normal - repeated sampling
• Standby times: The pause between measurements (available only in normal mode)
• IIR filter: Built-in noise reduction filter (useful for filtering environmental disturbances like opening windows or wind gusts)

Note: Higher oversampling settings take more time but are still quite fast (under 10ms)

Option 1: Default (backwards compatible)

bme.begin(BMEaddress, Humidity_oversampling, Temperature_oversampling, Pressure_oversampling, BME_mode, BME_standby, BME_IIR_filter)

Uses the default Wire object and automatically calls Wire.begin().

Option 2: Custom I2C Bus (for custom pins or multiple I2C buses)

bme.begin(&Wire, BMEaddress, Humidity_oversampling, Temperature_oversampling, Pressure_oversampling, BME_mode, BME_standby, BME_IIR_filter)

Allows you to specify a custom TwoWire object (e.g., &Wire, &Wire1) and initialize it yourself with custom pins.

Returns: boolean - true if initialization was successful, false otherwise

Example (Default):

// Uses default Wire object
if (!bme.begin(0x76, BME_H_X1, BME_T_X1, BME_P_X2, BME_NORMAL, BME_TSB_0_5MS, BME_FILTER_2)) {
  Serial.println("BME280 initialization failed!");
}

Example (Custom I2C Pins - ESP32):

// Define custom pins
#define SDA_PIN 21
#define SCL_PIN 22

// Initialize Wire with custom pins before calling begin
Wire.begin(SDA_PIN, SCL_PIN);

// Pass &Wire to use the initialized bus
if (!bme.begin(&Wire, 0x76, BME_H_X1, BME_T_X1, BME_P_X2, BME_NORMAL, BME_TSB_0_5MS, BME_FILTER_2)) {
  Serial.println("BME280 initialization failed!");
}

Reads the factory calibration registers. These registers contain fixed values written at the factory for each BME280 chip. This function must be called once in setup() to ensure proper measurements.

bme.calibrate(BMEaddress)

Returns: boolean - true if initialization was successful, false otherwise

Reads the temperature from the sensor.

bme.readTemperature(BMEaddress)

Returns: Struct BME_SensorData where bool isValid t/f based on success and data float - Temperature in degrees Celsius. See example.

Reads the relative humidity from the sensor.

bme.readHumidity(BMEaddress)

Returns: Struct BME_SensorData where bool isValid t/f based on success and data float - Humidity in %RH. See example.

Reads the atmospheric pressure from the sensor.

bme.readPressure(BMEaddress)

Returns: Struct BME_SensorData where bool isValid t/f based on success and data float - Pressure in hPa. See example.

Calculates altitude based on atmospheric pressure readings.

bme.readAltitude(BMEaddress, SeaLevelPressure_hPa)

Returns: Struct BME_SensorData where bool isValid t/f based on success and data float - Altitude in meters. See example.