How to Use BMP280: Examples, Pinouts, and Specs

The BMP280 is a precision sensor from Bosch that is designed for measuring barometric pressure and ambient temperature. It is widely used in applications such as weather stations, mobile devices, GPS enhancement for indoor navigation, and altitude tracking for drones and wearable devices.

• Pressure range: 300 to 1100 hPa (equivalent to +9000 to -500 m above/below sea level)
• Temperature range: -40 to +85°C
• Maximum resolution: 0.16 Pa and 0.01°C
• Relative accuracy: ±0.12 hPa, equivalent to ±1 m (at 25°C)
• Absolute accuracy: ±1 hPa (or ±8 m)
• Low power consumption: 2.7 µA at 1 Hz sampling rate
• I2C and SPI interfaces

To use the BMP280 in a circuit:

1. Connect the VDD pin to a power supply between 1.71 V and 3.6 V.
2. Connect the GND pin to the ground of the power supply.
3. For I2C communication, connect the SDI pin to the SDA line and the SCK pin to the SCL line. The SDO pin can be connected to ground or VDD to change the I2C address of the device.
4. For SPI communication, connect the SDI, SCK, and CSB pins to the corresponding SPI lines on your microcontroller.

• Use pull-up resistors on the I2C lines (SDA and SCL) if they are not already provided in the microcontroller.
• Keep the power supply stable and free of noise to ensure accurate readings.
• Avoid physical stress and contamination on the sensor to prevent damage or inaccurate readings.

#include <Wire.h>
#include <Adafruit_BMP280.h>

Adafruit_BMP280 bmp; // I2C Interface

void setup() {
  Serial.begin(9600);
  if (!bmp.begin(0x76)) {   // Change to 0x77 depending on your wiring
    Serial.println(F("Could not find a valid BMP280 sensor, check wiring!"));
    while (1);
  }

  // Set up oversampling and filter initialization
  bmp.setSampling(Adafruit_BMP280::MODE_NORMAL,     /* Operating Mode. */
                  Adafruit_BMP280::SAMPLING_X2,     /* Temp. oversampling */
                  Adafruit_BMP280::SAMPLING_X16,    /* Pressure oversampling */
                  Adafruit_BMP280::FILTER_X16,      /* Filtering. */
                  Adafruit_BMP280::STANDBY_MS_500); /* Standby time. */
}

void loop() {
    Serial.print(F("Temperature = "));
    Serial.print(bmp.readTemperature());
    Serial.println(" *C");

    Serial.print(F("Pressure = "));
    Serial.print(bmp.readPressure());
    Serial.println(" Pa");

    Serial.print(F("Approx altitude = "));
    Serial.print(bmp.readAltitude(1013.25)); /* Adjust the value to your local sea level pressure (in hPa) */
    Serial.println(" m");

    delay(2000);
}

• Sensor not detected: Ensure that the wiring is correct and that the sensor is properly powered. Check the I2C address if using I2C communication.
• Inaccurate readings: Verify that the sensor is not exposed to sudden temperature changes or physical stress. Check the power supply for stability.
• Noisy data: Implement averaging or a low-pass filter in software to smooth out the data.

Q: Can the BMP280 measure altitude? A: Yes, the BMP280 can estimate altitude based on the pressure reading and a reference sea level pressure.

Q: Is the BMP280 waterproof? A: No, the BMP280 is not waterproof and should be protected from moisture and contaminants.

Q: How do I change the I2C address of the BMP280? A: The I2C address can be changed by connecting the SDO pin to GND (0x76) or VDD (0x77).

Q: Can the BMP280 be used with both 3.3V and 5V systems? A: Yes, the BMP280 can be interfaced with both 3.3V and 5V systems, but the VDD must be within the specified range of 1.71 V to 3.6 V. Use level shifters if necessary when interfacing with a 5V system.

For further assistance, consult the manufacturer's datasheet and ensure that your implementation adheres to the recommended operating conditions.