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Guide for BME280 Sensor with Arduino (Pressure, Temperature, Humidity)

This guide shows how to use the BME280 sensor module with Arduino to read pressure, temperature, humidity and estimate altitude. We’ll show you how to wire the sensor, install the required libraries, and write a simple sketch to display the sensor readings.

Guide for BME280 Sensor with Arduino Pressure, Temperature, and Humidity

You might also like reading other BME280 guides:

Introducing BME280 Sensor Module

The BME280 sensor module reads barometric pressure, temperature, and humidity. Because pressure changes with altitude, you can also estimate altitude. There are several versions of this sensor module. The BME280 sensor uses I2C or SPI communication protocol to exchange data with a microcontroller.

We’re using the module illustrated in the figure below.

BME280 Sensor Module reads pressure, temperature, and humidity

This sensor communicates using I2C communication protocol, so the wiring is very simple. You connect the BME280 sensor to the Arduino Uno I2C pins as shown in the table below:

BME280Arduino
Vin5V
GNDGND
SCLA5
SDAA4

There are other versions of this sensor that can use either SPI or I2C communication protocols, like the module shown in the next figure:

BME280 with SPI and I2C

If you’re using one of these sensors, to use I2C communication protocol, use the following pins:

BME280Arduino
SCK (SCL Pin) A5
SDI (SDA pin) A4

If you use SPI communication protocol, you need to use the following pins:

BME280Arduino
SCK (SPI Clock) Pin 13
SDO (MISO) Pin 12
SDI (MOSI) Pin 11
CS (Chip Select) Pin 10

Parts Required

To complete this tutorial you need the following parts:

You can use the preceding links or go directly to MakerAdvisor.com/tools to find all the parts for your projects at the best price!

Schematic

Wire the BME280 sensor to your Arduino board as shown in the following schematic diagram.

Arduino BME280 Wiring Schematic Diagram

Installing the BME280 library

To get readings from the BME280 sensor module you need to use the Adafruit_BME280 library. Follow the next steps to install the library in your Arduino IDE:

Open your Arduino IDE and go to Sketch > Include Library > Manage Libraries. The Library Manager should open.

Search for “adafruit bme280 ” on the Search box and install the library.

Installing BME280 library in Arduino IDE

Installing the Adafruit_Sensor library

To use the BME280 library, you also need to install the Adafruit_Sensor library. Follow the next steps to install the library in your Arduino IDE:

Go to Sketch > Include Library > Manage Libraries and type “Adafruit Unified Sensor” in the search box. Scroll all the way down to find the library and install it.

Installing Adafruit Unified Sensor driver library

After installing the libraries, restart your Arduino IDE.

Reading Pressure, Temperature, and Humidity

To read pressure, temperature, and humidity we’ll use a sketch example from the library.

Arduino BME280 Guide Reading Temperature, Humidity, and Pressure Sketch

After installing the BME280 library, and the Adafruit_Sensor library, open the Arduino IDE and, go to File > Examples > Adafruit BME280 library > bme280 test.

/*
 * Complete Project Details https://randomnerdtutorials.com
*/

#include <Wire.h>
#include <SPI.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>

#define BME_SCK 13
#define BME_MISO 12
#define BME_MOSI 11
#define BME_CS 10

#define SEALEVELPRESSURE_HPA (1013.25)

Adafruit_BME280 bme; // I2C
//Adafruit_BME280 bme(BME_CS); // hardware SPI
//Adafruit_BME280 bme(BME_CS, BME_MOSI, BME_MISO, BME_SCK); // software SPI

unsigned long delayTime;

void setup() {
  Serial.begin(9600);
  Serial.println(F("BME280 test"));

  bool status;
  
  // default settings
  // (you can also pass in a Wire library object like &Wire2)
  status = bme.begin();  
  if (!status) {
    Serial.println("Could not find a valid BME280 sensor, check wiring!");
    while (1);
  }
  
  Serial.println("-- Default Test --");
  delayTime = 1000;

  Serial.println();
}


void loop() { 
  printValues();
  delay(delayTime);
}


void printValues() {
  Serial.print("Temperature = ");
  Serial.print(bme.readTemperature());
  Serial.println(" *C");
  
  // Convert temperature to Fahrenheit
  /*Serial.print("Temperature = ");
  Serial.print(1.8 * bme.readTemperature() + 32);
  Serial.println(" *F");*/
  
  Serial.print("Pressure = ");
  Serial.print(bme.readPressure() / 100.0F);
  Serial.println(" hPa");
  
  Serial.print("Approx. Altitude = ");
  Serial.print(bme.readAltitude(SEALEVELPRESSURE_HPA));
  Serial.println(" m");
  
  Serial.print("Humidity = ");
  Serial.print(bme.readHumidity());
  Serial.println(" %");
  
  Serial.println();
}

View raw code

How the Code Works

Continue reading this section to learn how the code works, or skip to the “Demonstration” section.

Libraries

The code starts by including the needed libraries: the wire library to use I2C, and the Adafruit_Sensor and Adafruit_BME280 libraries to interface with the BME280 sensor.

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>

SPI communication

As we’re going to use I2C communication, the following lines that define the SPI pins are commented:

/*#define BME_SCK 13
#define BME_MISO 12
#define BME_MOSI 11
#define BME_CS 10*/

Sea level pressure

A variable called SEALEVELPRESSURE_HPA is created.

#define SEALEVELPRESSURE_HPA (1013.25)

This variable saves the pressure at the sea level in hectopascal (is equivalent to milibar). This variable is used to estimate the altitude for a given pressure by comparing it with the sea level pressure. This example uses the default value, but for more accurate results, replace the value with the current sea level pressure at your location.

I2C

This example uses I2C communication protocol by default. As you can see, you just need to create an Adafruit_BME280 object called bme.

Adafruit_BME280 bme; // I2C

To use SPI, you need to comment this previous line and uncomment one of the following lines.

//Adafruit_BME280 bme(BME_CS); // hardware SPI
//Adafruit_BME280 bme(BME_CS, BME_MOSI, BME_MISO, BME_SCK); // software SPI

setup()

In the setup(), start a serial communication:

Serial.begin(9600);

And the sensor is initialized:

status = bme.begin(); 
if (!status) {
  Serial.println("Could not find a valid BME280 sensor, check wiring!");
  while (1);
}

Note: when testing the sensor, if you can’t get any sensor readings, you may need to find your BME280 sensor I2C address. With the BME280 wired to your Arduino, run this I2C scanner sketch to check the address of your sensor. Then, pass the address to the begin() method.

Printing values

In the loop(), the printValues() function reads the values from the BME280 and prints the results in the Serial Monitor.

void loop() { 
  printValues();
  delay(delayTime);
}

Reading temperature, humidity, pressure, and estimate altitude is as simple as using the following methods on the bme object:

  • bme.readTemperature() – reads temperature in Celsius;
  • bme.readHumidity() – reads absolute humidity;
  • bme.readPressure() – reads pressure in hPa (hectoPascal = millibar);
  • bme.readAltitude(SEALEVELPRESSURE_HPA) – estimates altitude in meters based on the pressure at the sea level.

Demonstration

Arduino BME280 Read Temperature, Humidity, and Pressure Sketch

Upload the code to your Arduino Board.

Upload Arduino Sketch for BME280 Sensor

Open the Serial Monitor at a baud rate of 9600.

Upload Arduino Sketch for BME280 Sensor

You should see the readings displayed on the Serial Monitor.

Arduino Sketch for BME280 Sensor Demonstration Serial Monitor

Wrapping Up

The BME280 provides an easy and inexpensive way to get pressure, temperature and humidity readings. The sensor communicates via I2C communication protocol, which means that wiring is very simple, you just need to connect the sensor to the Arduino I2C pins.

Writing the code to get the sensor readings is also very straightforward thanks to the BME280_Adafruit library. You just need to use the readTemperature(), readHumidity() and readPressure() methods. You can also estimate altitude using the readAltitude() method.

We have guides for other sensors and modules with the Arduino that you may find useful:

If you want to learn more about Arduino, take a look at our resources:

Thanks for reading.



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42 thoughts on “Guide for BME280 Sensor with Arduino (Pressure, Temperature, Humidity)”

  1. Would be great to see this BME280 on an ESP 01 for outdoor and read to your mobile device or better to another indoor ESP8266 with LCD 🙂 Thanks for the great work. You guys are awesome. Thumbs up!

    Reply

      • Hello; Really like this tutorial. One thing you might consider is: obtaining the sealevel pressure from the web as this changes frequently. here is an example of a link to the information: “https://api.weather.gov/stations/KTLH/observations/latest?require_qc=true”
        This returns a json table with the data in it. I’m working on this and having trouble parsing the table. Maybe you can figure this out. The link above is just one example provoded by the State of Florida. Maybe other States have similar services.

        Reply

  2. Excellent article. There is a similar Bosch sensor called the BMP280 which has Pressure/Temperature but does not include humidity. Many ebay sellers confuse the two and sell the BMP280 as the BME280. There are 3 ways to identify the BME280 :
    1. Shape – the metal BME sensor is square; the BMP is rectangular.
    2. Location of Vent Hole – On LHS for BME; or RHS for BMP.
    3. Code – the BME has P in the code marking; the BMP has K in the code.
    Also, the BME boards are often 3-4 times the price of the BMP boards.
    To avoid frustration, check that the sensor you have bought is the BME280 and not the BMP280.

    Reply

    • Dang.. now I have to go check which chip is on my breakout boards and my return window has already passed.. That will serve me right for not checking properly!

      Reply

    • Additionally, the BMP280 restricts what you can calculate, whilethe BME280 allows you to calculate dew point and humidex (feels like) temperatures. I bought BME280s from Amazon and received BMP280s instead. Had one soldered in place before I discovered the issue. Wish the boards were marked clearly.

      Reply

    • Duncan, You need the qnh value for your nearest aerodrome

      Here is mine (1015hpa)

      skybrary.aero/index.php/EGNX

      Reply

      • My point was that Rui should show a method in the tutorial, not just leave it hanging in mid air…

        Thanks

        Reply

    • Hi Duncam.
      I think it depends on where you live.
      Here in Portugal, I cant get the pressure from IPMA website (portuguese meteorology website).
      Try searching your country + sea level pressure on google and see the results.
      Regards,
      Sara

      Reply

      • I believe from my flight tutorials (when I was paying attention) that the air pressure at sea level is standardised since the amount of air above the sea (and that’s the sea as in the ocean!) is broadly similar no matter where we are on the planet.

        29.92 inches of Hg or 1013.25 hectopascals in real money.

        Reply

        • I should add that this varies throughout the year but standard air pressure is often close enough. I can’t find a way to edit my comment (sorry for the D’OH).

          Local weather stations generally keep a calibrated ASL pressure in case you need to calibrate. Of course, you can also calibrate your sensor by going to the seaside or if you know your height ASL you can do it in reverse.

          Reply

  4. Interesting post.
    With the BME280 it is important to realise that by default it is in automode, taking continuous readings. This will warm up the chip, affecting the read temperature.
    It is better to use the BME in “Forced mode” and to set the sampling rate:
    bme.setSampling(Adafruit_BME280::MODE_FORCED,
    Adafruit_BME280::SAMPLING_X1, // temperature
    Adafruit_BME280::SAMPLING_X1, // pressure
    Adafruit_BME280::SAMPLING_X1, // humidity
    Adafruit_BME280::FILTER_OFF );

    Reply

  5. Hi Sara and Rui,

    What to do if I want to use BME280 twice.
    For my greenhouse I want to know T and RH outside and inside.
    Is that possible anyway?
    Cheers
    Gerard

    Reply

  6. I have a remote debugger via telnet being used in my setup. But when my dme.begin is called and it can’t find or has a problem with my dme280, it reboots. Is there a way to not make it reboot and keep trying every 5 seconds or so? And let it go ahead and connect to wifi so remote debugging can continue?

    Reply

  7. what would be the syntax if I wanted to read the values, then convert them all to different units, then use Serial.print?

    Reply

  9. I am trying to use this sketch to read the BME280 sensor but I am running into a snag. For a long time I could not get anything to print on the Serial Monitor. I finally found a web page that said that the Bosch BME280 board has it address set to “0x76”. In checking the Adafruit_BME280.cpp file that the address it is looking for is “0x77”. But it can be changed by connecting the SDO pin to ground. That go it to print the “BME280 Test” but nothing else prints so I am thinking it is stopping at the “while(1);” So I don’t know why it is not reading the sensor data. Is the sensor defective or what? Any ideas? Let me know via email with any way to fix this. Thanks!

    Reply

  10. Thanks Sara, I have it working fine now. I used the i2c/12C scanner and found the address to be “0x77” but the problems that I was having showed up. I had purchased some other ones on Amazon and when I scanned them they were not addressed at all.
    I guess they scammed me although it wasn’t very expensive. They are now in the trash and because of the lack of address is what had me so confused .

    Reply

  11. Hello, I have a problem with this sensor, the address is 0x76 but I receive following error: Could not find a valid BME280 sensor, check wiring!.
    How can I resolve this problem?

    Reply

  12. Hello Rui and Sara,
    many thanks for all your informative tutorials.
    Something of concern regarding voltage levels. The Arduino is a 5v device and the BME280 according to the bosch data sheet is 3.3V.
    Why your wiring does not include some form of level shifting? is there not danger of damaging the sensor?
    Best regards
    Andre

    Reply

    • Hi.
      This sensor module works either with 5V or 3.3V. It comes with a 3.3V regulator and level shifting so you can use it with a 3.3V or 5V microcontroller.
      Regards,
      Sara

      Reply

    • I created the symbol and footprint myself. KiCAD is actually very easy to work with. I found a site that had the dimensions of the BME280 6-pin module, but it didn’t sound right. So.. I measured the module and found the dimensions listed on the site (not this site) were wrong. Moral of the story is — I could have measured it and created the symbol and footprint way faster than the time I wasted wondering where I could find an already-created symbol.

      Reply

  15. Hi Sara,
    I hope you’re doing well. I want to use multiple BME280 sensors with an M5Stack Basic for a project I’m working on. Do you have any suggestions or recommendations on how to best implement this setup? Specifically, I’m interested to programmatically enable I2C pull-up resistors on the board. Will it work? Additionally, if you have any tips on ensuring reliable data readings, that would be incredibly helpful (I am planning on recording data for every 10 seconds using Ambient cloud service).

    Reply

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