BMP280 Arduino: Complete Barometric Pressure Sensor Guide

After working with dozens of environmental sensors across various PCB projects, the BMP280 Arduino combination remains my go-to solution for barometric pressure measurement. This sensor from Bosch delivers professional-grade accuracy at a fraction of the cost of industrial barometers, making it ideal for weather stations, altimeters, and IoT environmental monitoring.

The BMP280 represents the evolution of the BMP085/BMP180/BMP183 sensor family, bringing improved accuracy, lower power consumption, and more flexible configuration options. Unlike simpler analog sensors, the BMP280 handles all the complex compensation mathematics internally, delivering calibrated pressure and temperature readings over I2C or SPI interfaces.

What is the BMP280 Barometric Pressure Sensor?

The BMP280 is a digital barometric pressure and temperature sensor designed by Bosch Sensortec for portable and wearable applications. At its core sits a piezoresistive sensing element paired with a mixed-signal ASIC that handles analog-to-digital conversion, calibration compensation, and digital communication.

What makes this sensor particularly useful for Arduino projects is the internal calibration data stored in non-volatile memory. Every BMP280 chip contains factory-programmed compensation parameters that account for manufacturing variations, so you get accurate readings straight out of the package without manual calibration.

The sensor measures atmospheric pressure by detecting how a silicon diaphragm deforms under pressure. This deformation changes the electrical resistance of piezoresistive elements integrated into the diaphragm, which the internal ADC converts to digital values. The built-in temperature sensor provides data for compensating pressure readings against thermal drift.

BMP280 Technical Specifications

Before integrating any sensor into a PCB design, understanding the electrical characteristics prevents problems during prototyping:

Parameter	Value
Supply Voltage (VDD)	1.71V – 3.6V
Interface Voltage (VDDIO)	1.2V – 3.6V
Pressure Range	300 – 1100 hPa
Pressure Accuracy	±1 hPa (typical)
Pressure Resolution	0.16 Pa
Temperature Range	-40°C to +85°C
Temperature Accuracy	±1.0°C
Temperature Resolution	0.01°C
Current (Normal Mode)	2.74 µA @ 1Hz
Current (Sleep Mode)	0.1 µA
I2C Speed	Up to 3.4 MHz
SPI Speed	Up to 10 MHz

One specification that catches many engineers off guard: the BMP280 is NOT 5V tolerant. Operating from 3.3V is mandatory. Most breakout modules include onboard voltage regulators, but if you’re designing a custom PCB, plan your power rails accordingly.

BMP280 Module Pinout Configuration

Most BMP280 breakout boards expose six pins:

Pin	Name	Function
VCC	Power Supply	3.3V – 5V (with onboard regulator)
GND	Ground	Common ground reference
SCL	I2C Clock / SPI Clock	Serial clock input
SDA	I2C Data / SPI MOSI	Serial data (bidirectional for I2C)
CSB	Chip Select	LOW for SPI, HIGH for I2C
SDO	SPI MISO / I2C Address	Data out for SPI, address select for I2C

The CSB and SDO pins serve dual purposes depending on your communication protocol choice. For I2C operation, CSB must be pulled HIGH (most modules do this internally), and SDO determines the I2C address.

BMP280 I2C Address Selection

SDO Pin State	I2C Address
Connected to GND	0x76
Connected to VDD	0x77

Most budget modules pull SDO to GND by default, giving address 0x76. If you’re using multiple BMP280 sensors on the same I2C bus, connect SDO to VDD on one sensor to get address 0x77.

Wiring BMP280 to Arduino

The I2C connection requires just four wires and works reliably in most configurations:

I2C Wiring Configuration

BMP280 Pin	Arduino UNO	Arduino Mega	Arduino Leonardo
VCC	3.3V or 5V*	3.3V or 5V*	3.3V or 5V*
GND	GND	GND	GND
SCL	A5	D21	D3
SDA	A4	D20	D2
CSB	Not connected	Not connected	Not connected
SDO	Not connected	Not connected	Not connected

*With breakout module that has onboard regulator

SPI Wiring Configuration

BMP280 Pin	Arduino UNO	Arduino Mega
VCC	3.3V or 5V*	3.3V or 5V*
GND	GND	GND
SCL (SCK)	D13	D52
SDA (MOSI)	D11	D51
SDO (MISO)	D12	D50
CSB (CS)	D10	D53

For bare BMP280 chips without a breakout board, never exceed 3.6V on any pin. Level shifters are mandatory when interfacing with 5V Arduino boards.

BMP280 Operating Modes

The BMP280 offers three power modes that balance measurement frequency against power consumption:

Mode	Description	Use Case
Sleep	No measurements, lowest power	Battery standby
Forced	Single measurement, returns to sleep	Periodic sampling
Normal	Continuous measurements with standby	Real-time monitoring

Sleep Mode draws only 0.1µA, making it ideal for battery-powered applications where measurements happen infrequently.

Forced Mode performs one measurement when triggered and automatically returns to sleep. This gives you precise control over sampling timing and is useful when synchronizing with other sensors.

Normal Mode continuously cycles between measurement and standby periods. The IIR filter works best in this mode, smoothing out short-term pressure fluctuations caused by wind or door slams.

Oversampling and IIR Filter Settings

The BMP280 provides extensive configuration options for balancing accuracy, noise, and power consumption:

Oversampling Options

Setting	Multiplier	Noise Reduction	Power Increase
Ultra Low Power	x1	Minimal	Lowest
Low Power	x2	Low	Low
Standard	x4	Medium	Medium
High Resolution	x8	High	High
Ultra High Resolution	x16	Maximum	Highest

Higher oversampling reduces noise by averaging multiple internal measurements, but increases current consumption and measurement time.

IIR Filter Coefficients

Filter Setting	Response Time	Noise Filtering
Off	Fastest	None
2x	Fast	Light
4x	Medium	Moderate
8x	Slow	Strong
16x	Slowest	Maximum

The IIR (Infinite Impulse Response) filter is particularly valuable for altitude measurements. It smooths out rapid pressure changes from environmental disturbances while still tracking gradual changes in altitude.

Basic BMP280 Arduino Code

Here’s a tested starting point using the Adafruit library:

#include <Wire.h>

#include <Adafruit_BMP280.h>

Adafruit_BMP280 bmp;  // I2C interface

void setup() {

  Serial.begin(9600);

  Serial.println(“BMP280 Barometric Pressure Sensor”);

  // Initialize with I2C address 0x76

  if (!bmp.begin(0x76)) {

    Serial.println(“Could not find BMP280 sensor!”);

    Serial.println(“Check wiring or try address 0x77”);

    while (1);

  }

  // Configure sensor settings

  bmp.setSampling(Adafruit_BMP280::MODE_NORMAL,     // Operating mode

                  Adafruit_BMP280::SAMPLING_X2,     // Temp oversampling

                  Adafruit_BMP280::SAMPLING_X16,    // Pressure oversampling

                  Adafruit_BMP280::FILTER_X16,      // IIR filter

                  Adafruit_BMP280::STANDBY_MS_500); // Standby time

  Serial.println(“Sensor initialized successfully”);

}

void loop() {

  float temperature = bmp.readTemperature();

  float pressure = bmp.readPressure();

  float altitude = bmp.readAltitude(1013.25);  // Sea level pressure in hPa

  Serial.print(“Temperature: “);

  Serial.print(temperature);

  Serial.println(” °C”);

  Serial.print(“Pressure: “);

  Serial.print(pressure / 100.0);  // Convert Pa to hPa

  Serial.println(” hPa”);

  Serial.print(“Altitude: “);

  Serial.print(altitude);

  Serial.println(” m”);

  Serial.println();

  delay(2000);

}

If initialization fails with address 0x76, try 0x77. Different manufacturers use different default configurations.

Understanding Pressure Units and Conversions

Barometric pressure gets reported in various units depending on the application:

Unit	Abbreviation	Conversion from Pascal
Pascal	Pa	Base unit
Hectopascal	hPa	Pa / 100
Millibar	mbar	Pa / 100 (same as hPa)
Atmosphere	atm	Pa / 101325
Inches of Mercury	inHg	Pa / 3386.39
Millimeters of Mercury	mmHg	Pa / 133.322

The BMP280 library returns pressure in Pascals (Pa). Weather reports typically use hectopascals (hPa) or millibars (mbar), which are numerically identical. Standard atmospheric pressure at sea level is 1013.25 hPa.

Calculating Altitude from Pressure

The relationship between atmospheric pressure and altitude follows a well-defined physical formula. The BMP280 library includes an altitude function, but understanding the math helps with troubleshooting:

// Calculate altitude from pressure

float calculateAltitude(float pressure, float seaLevelPressure) {

  return 44330.0 * (1.0 – pow(pressure / seaLevelPressure, 0.1903));

}

Critical point: Accurate altitude calculation requires knowing the current sea-level pressure at your location. Weather services report this value, which changes daily with weather patterns. Using an incorrect sea-level pressure introduces significant altitude errors.

For relative altitude measurements (detecting floor changes, elevator movement), the absolute accuracy matters less than consistency. Store a reference pressure at your starting point and calculate altitude changes relative to that baseline.

BMP280 vs BME280 Comparison

The BME280 is the humidity-sensing sibling of the BMP280:

Feature	BMP280	BME280
Temperature	Yes	Yes
Pressure	Yes	Yes
Humidity	No	Yes
I2C Address	0x76/0x77	0x76/0x77
Package	LGA	LGA
Price	Lower	Higher

If your project needs humidity data, the BME280 is worth the extra cost. For pure pressure and temperature measurements, the BMP280 delivers identical performance at a lower price point.

Both sensors share the same footprint and are largely code-compatible. The Adafruit BME280 library works with BMP280 sensors for temperature and pressure readings.

Common Troubleshooting Issues

From debugging numerous BMP280 installations, these problems appear most frequently:

Sensor Not Found Error: The most common cause is incorrect I2C address. Try both 0x76 and 0x77. Also verify that CSB is not accidentally pulled LOW, which puts the sensor in SPI mode.

Inconsistent Readings: Check your power supply stability. The BMP280 is sensitive to voltage ripple, especially during ADC conversion. Add a 100nF decoupling capacitor close to the VDD pin.

Temperature Reading Too High: The BMP280 measures its own die temperature, not ambient temperature. Self-heating from the internal heater and nearby components can raise readings several degrees above ambient.

Altitude Drift: Barometric pressure changes with weather, causing altitude readings to drift even when stationary. For accurate absolute altitude, update the sea-level pressure reference regularly from weather services.

First Reading Invalid: After power-on or mode change, the first reading may contain stale or invalid data. Discard the first reading and use subsequent measurements.

Practical Applications for BMP280 Arduino Projects

Based on deployment experience, these applications work well with the BMP280:

Weather Station

Monitor barometric pressure trends for local weather forecasting. Rapidly falling pressure often precedes storms, while rising pressure suggests fair weather approaching.

Drone Altitude Hold

The high-resolution pressure measurements enable altitude hold functionality in multirotor aircraft. The fast response time and IIR filter help maintain stable hover height.

Indoor Navigation

Detect floor changes in buildings using pressure differences. Each floor typically represents about 3-4 meters of altitude change, which the BMP280 resolves easily.

HVAC Monitoring

Monitor differential pressure across air filters to detect when replacement is needed. Clean filters show minimal pressure drop, while clogged filters exhibit increased resistance.

Rocket Altimetry

Record peak altitude of model rockets. The fast sampling rate captures rapid altitude changes during flight.

Useful Resources and Downloads

Datasheets and Documentation

• Bosch BMP280 Datasheet: Complete technical specifications and register descriptions
• Adafruit BMP280 Learning Guide: Step-by-step tutorial with wiring diagrams
• Bosch Sensortec GitHub: Official API and driver code

Arduino Libraries

• Adafruit BMP280 Library: Available via Arduino Library Manager
• BMP280_DEV Library: Non-blocking operation with advanced features
• SparkFun BME280 Library: Compatible with BMP280 sensors

Breakout Boards

• Adafruit BMP280 Breakout: Includes voltage regulator and level shifters
• GY-BMP280 Module: Budget option, verify voltage compatibility
• SparkFun BMP280 Breakout: Qwiic connector for easy wiring

Frequently Asked Questions

What is the difference between BMP280 and BME280?

The BMP280 measures temperature and barometric pressure, while the BME280 adds humidity sensing capability. Both sensors share the same physical package, pinout, and pressure/temperature specifications. The BME280 costs slightly more due to the additional humidity sensor. If your project requires humidity data, choose the BME280. For pressure and temperature only, the BMP280 is more cost-effective.

Why does my BMP280 show wrong altitude readings?

Altitude calculations depend on knowing the current sea-level pressure at your location. The readAltitude() function uses a reference pressure value that must match actual local conditions. Weather-related pressure changes cause altitude drift, so absolute altitude accuracy requires regular reference updates. For relative altitude measurements (floor detection, elevator tracking), use a baseline pressure reading from a known reference point instead of absolute altitude.

Can I use BMP280 with 5V Arduino boards?

The BMP280 chip itself operates at 3.3V maximum and is not 5V tolerant. However, most breakout modules include onboard voltage regulators and level shifters that allow safe connection to 5V Arduino boards like the Uno or Mega. Always check your specific module’s documentation. If using a bare BMP280 chip or module without level shifting, you must use external level shifters for 5V compatibility.

How do I improve BMP280 measurement accuracy?

Increase pressure oversampling to x16 and enable the IIR filter with coefficient x16 for maximum noise reduction. Ensure stable power supply with adequate decoupling capacitors. Allow the sensor to stabilize for several minutes after power-on before taking critical measurements. For temperature-sensitive applications, account for self-heating effects by comparing readings against a separate ambient temperature sensor.

Why does my BMP280 initialization fail with “sensor not found” error?

This typically indicates an I2C communication problem. First, verify wiring connections to the correct I2C pins for your Arduino board (A4/A5 for Uno, 20/21 for Mega). Try both I2C addresses (0x76 and 0x77) as different modules use different defaults. Ensure the CSB pin is HIGH or unconnected for I2C mode. Run an I2C scanner sketch to verify the sensor appears on the bus. Check for missing or inadequate pull-up resistors on the I2C lines.

Final Thoughts

The BMP280 Arduino combination delivers exceptional pressure measurement capability for the price point. The sensor’s built-in calibration, flexible operating modes, and comprehensive filtering options make it suitable for everything from simple weather monitoring to demanding aerospace applications.

Success with the BMP280 comes down to proper power supply design, understanding the relationship between oversampling settings and noise performance, and recognizing that altitude calculations require accurate sea-level pressure references. Get these fundamentals right, and you’ll have reliable barometric data for your environmental monitoring, drone control, or weather station projects.

The sensor’s low power consumption also makes it excellent for battery-powered IoT applications where long runtime matters. Combined with sleep mode and forced measurement triggering, a BMP280-based weather logger can run for months on modest battery capacity while still providing accurate atmospheric data.