Overview

The BMP388 is a 24-bit high-precision digital barometric pressure and temperature sensor manufactured by Bosch Sensortec. Built as the high-performance successor to the BMP280, it features an ultra-small $2.0 \times 2.0\text{ mm}$ 10-pin LGA package, a 512-byte FIFO buffer, and an advanced MEMS piezo-resistive pressure sensing element.

Offering exceptional relative altitude accuracy of $\pm 0.5\text{ meters}$ ($\pm 8\text{ Pa}$) and pressure noise down to $0.08\text{ Pa}$ RMS, the BMP388 is the preferred altimeter sensor for drone flight controllers (altitude-hold mode), indoor floor-level navigation, vertical velocity estimation, and precision weather stations.

Quick reference

Pinout

Breakout modules expose a 6-pin 0.1" (2.54 mm) header or Qwiic / STEMMA QT connector:

Specifications

Hypsometric Barometric Altitude Formula

To compute altitude $h$ (in meters) from measured barometric pressure $P$ (in hPa):

$h = \frac{T_0}{L} \times \left[ 1 - \left( \frac{P}{P_0} \right)^{\frac{R \cdot L}{g \cdot M}} \right] \approx 44330 \times \left[ 1 - \left( \frac{P}{1013.25} \right)^{0.1903} \right]$

• $P$: Measured pressure in hPa.
• $P_0$: Sea level reference pressure ($1013.25\text{ hPa}$ nominal, or current local airport QNH setting).

Wiring

Example

#include <Wire.h>
#include <SPI.h>
#include <Adafruit_BMP388.h>

#define SEALEVELPRESSURE_HPA (1013.25)

Adafruit_BMP388 bmp;

void setup() {
  Serial.begin(115200);
  while (!Serial) delay(10);

  Serial.println("BMP388 test");

  if (!bmp.begin_I2C(0x77)) { // Default address 0x77
    Serial.println("Could not find BMP388 sensor! Check CS and SDO pins.");
    while (1);
  }

  // Set up oversampling and filter initialization
  bmp.setTemperatureOversampling(BMP3_OVERSAMPLING_8X);
  bmp.setPressureOversampling(BMP3_OVERSAMPLING_32X);
  bmp.setIIRFilterCoeff(BMP3_IIR_FILTER_COEFF_3);
  bmp.setOutputDataRate(BMP3_ODR_50_HZ);
}

void loop() {
  if (!bmp.performReading()) {
    Serial.println("Failed to perform reading");
    return;
  }

  Serial.print("Temperature = "); Serial.print(bmp.temperature); Serial.println(" *C");
  Serial.print("Pressure = "); Serial.print(bmp.pressure / 100.0); Serial.println(" hPa");
  Serial.print("Approx Altitude = "); Serial.print(bmp.readAltitude(SEALEVELPRESSURE_HPA)); Serial.println(" m");

  delay(200);
}

Common mistakes

• Leaving CS floating in $I^2C$ mode: If CS is unconnected, electrical noise drops the IC into SPI mode. Tie CS High to 3.3V for $I^2C$ mode.
• Exposing sensor aperture to direct sunlight or air drafts: Air currents from drone propellers or ambient sunlight thermal radiation cause pressure fluctuation errors up to $\pm 20\text{ Pa}$ ($\pm 1.5\text{ m}$). Cover the sensor with open-cell dark foam in drone builds.

Notes

• BMP280 vs BMP388: The BMP388 improves relative altitude precision from $\pm 1.0\text{ m}$ down to $\pm 0.5\text{ m}$ and lowers pressure noise significantly.