BME280 is a small size sensor with the ability to sense humidity, temperature, pressure, and also altitude. We will learn how to use the BME/BMP280 sensor. but before that, let’s see the sensor detail first.
- 3%humidity accuracy
- barometric pressure with 1 hPa absolute accuracy
- temperature with 1.0 degrees Celcius of accuracy.
With this data, you can use this sensor as an altimeter with more than 1-meter accuracy.
We can see that it has SDA and SCL pins, so this module uses the I2C communication protocol. This module actually has 2 sensors inside, that is the humidity sensor and the pressure sensor. And the size is quite small.
Wiring Diagram
Now let’s connect this sensor with an Arduino. This is the wiring diagram, just as usual for the i2c device. The VCC to 5V of Arduino, GND to GND, SDA to A4, and SCL to A5. When you are sure the wiring is correct now, let’s move to Arduino IDE.
Sketch and Library
You need to download BME library you can download it directly from this link or you can use the library manager. To use library manager you should open the library manager and search for BME280. I will choose the last version and install it.
Before that we can make sure the address of this device by using i2cscanner, here’s the I2C scanner sketch.
// -------------------------------------- // i2c_scanner // // Version 1 // This program (or code that looks like it) // can be found in many places. // For example on the Arduino.cc forum. // The original author is not know. // Version 2, Juni 2012, Using Arduino 1.0.1 // Adapted to be as simple as possible by Arduino.cc user Krodal // Version 3, Feb 26 2013 // V3 by louarnold // Version 4, March 3, 2013, Using Arduino 1.0.3 // by Arduino.cc user Krodal. // Changes by louarnold removed. // Scanning addresses changed from 0...127 to 1...119, // according to the i2c scanner by Nick Gammon // http://www.gammon.com.au/forum/?id=10896 // Version 5, March 28, 2013 // As version 4, but address scans now to 127. // A sensor seems to use address 120. // Version 6, November 27, 2015. // Added waiting for the Leonardo serial communication. // // // This sketch tests the standard 7-bit addresses // Devices with higher bit address might not be seen properly. // #include <Wire.h> void setup() { Wire.begin(); Serial.begin(9600); while (!Serial); // Leonardo: wait for serial monitor Serial.println("\nI2C Scanner"); } void loop() { byte error, address; int nDevices; Serial.println("Scanning..."); nDevices = 0; for(address = 1; address < 127; address++ ) { // The i2c_scanner uses the return value of // the Write.endTransmisstion to see if // a device did acknowledge to the address. Wire.beginTransmission(address); error = Wire.endTransmission(); if (error == 0) { Serial.print("I2C device found at address 0x"); if (address<16) Serial.print("0"); Serial.print(address,HEX); Serial.println(" !"); nDevices++; } else if (error==4) { Serial.print("Unknown error at address 0x"); if (address<16) Serial.print("0"); Serial.println(address,HEX); } } if (nDevices == 0) Serial.println("No I2C devices found\n"); else Serial.println("done\n"); delay(500); // wait 5 seconds for next scan }
Open serial monitor after upload, and you should get the address of the sensor. for me it’s 0x76
Now open the libaray example folder, and open the file named bme280test.
We should pass the i2c address we found with i2c scanner at bme.begin. Here’s the code with 0x76 address.
/*************************************************************************** This is a library for the BME280 humidity, temperature & pressure sensor Designed specifically to work with the Adafruit BME280 Breakout ----> http://www.adafruit.com/products/2650 These sensors use I2C or SPI to communicate, 2 or 4 pins are required to interface. The device's I2C address is either 0x76 or 0x77. Adafruit invests time and resources providing this open source code, please support Adafruit andopen-source hardware by purchasing products from Adafruit! Written by Limor Fried & Kevin Townsend for Adafruit Industries. BSD license, all text above must be included in any redistribution See the LICENSE file for details. ***************************************************************************/ #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); while(!Serial); // time to get serial running Serial.println(F("BME280 test")); unsigned status; // default settings status = bme.begin(0x76); // You can also pass in a Wire library object like &Wire2 // status = bme.begin(0x76, &Wire2) if (!status) { Serial.println("Could not find a valid BME280 sensor, check wiring, address, sensor ID!"); Serial.print("SensorID was: 0x"); Serial.println(bme.sensorID(),16); Serial.print(" ID of 0xFF probably means a bad address, a BMP 180 or BMP 085\n"); Serial.print(" ID of 0x56-0x58 represents a BMP 280,\n"); Serial.print(" ID of 0x60 represents a BME 280.\n"); Serial.print(" ID of 0x61 represents a BME 680.\n"); while (1) delay(10); } 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"); 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(); }
After the
upload is complete open the serial monitor anddd viooollaaaaa….
We get the
data, it has temperature, barometric pressure, altitude and also humidity.
So we already know how to use or read this BME280 sensor with an Arduino. You can also watch this tutorial video in our youtube video :