The GY-BME280 is a high precision combined digital pressure, humidity and temperature sensor module with I2C and SPI interfaces.
The BME280 is a precision Bosch sensor that can be used in many applications from weather monitoring to gaming controls to altitude measurements with enough precision to know if an object has been lifted a couple of feet.
The BME280 is a higher performance version of the BMP280 with much better noise performance and also includes humidity sensing the BMP280 does not have.
Compared to the BME280 I2C module, this one exposes the SPI interface along with I2C but it is 3.3V operation only while the BME280 I2C module has a built in regulator and logic level shifters and will operate at either 5V or 3.3V.
The temperature measurement is used internally to compensate the pressure and humidity sensors and is also available to estimate the ambient temperature as well.
The device has numerous sampling and filtering options that can be employed to optimize the device for specific applications.
Note that this device operates at 3.3V. If it is being used with a 5V MCU, it should be powered off the 3.3V output. The good news is that the I2C interface is an open-drain interface with 10K pull-up resistors to the modules Vcc (3.3V) and so it can be used without level shifting. If you want to use the SPI interface instead, it will need to be level shifted to avoid possible damage to the module.
Module Connections
The module brings out the following connections.
1 x 6 Header
VCC = 1.7 to 3.6V. Connect to 3.3V output of the MCU
GND = Ground
SCL = Clock (SCL / SCK) for I2C and SPI
SDA = Data (SDA / SDI) for I2C and SPI
CSB = Chip Select Bus. Logic HIGH for I2C (default), logic LOW for SPI
SDO = Data Out (SDO) for SPI. Sets I2C address for I2C
Measuring Temperature
The BME280 can measure temperature over the range of -40 to 80°C.
Full accuracy of ±1.0°C is obtained over the range of 0 to 65°C. Outside that range, the accuracy can decrease to ±1.5°C
Measuring Humidity
The BME280 can measure humidity over the range of 0 to 100% with an accuracy of ±3%.
The sensor can measure up to 100% humidity over the temperature range of 0 to 60°C. At very high or low temperatures, the maximum measurable humidity decreases per the graph on page 10 of the datasheet.
Measuring Pressure
The BME280 can measure pressure over the range of 300 to 1100 hPa with excellent accuracy of ±1.0 hPa.
Full accuracy is obtained over the temperature range of 0 to 65°C. This gives an elevation measurement accuracy of approximately ±1 meter. Outside that range the accuracy can decrease to ±1.7 hPa
Applications of GY-BMP280 Module
Enhancement of GPS navigation (e.g. time-to-first-fix improvement, dead-reckoning, slope detection)
Indoor navigation (floor detection, elevator detection)
Outdoor navigation, leisure and sports applications
