In the earlier days weather parameters like ambient temperature, humidity and barometric pressure were measured with separate analog instruments: thermometer, hygrometer and barometer.But today the market is flooded with cheap and efficient digital sensors that can be used to measure a variety of environmental parameters.The best examples are sensors like DHT11, DHT 22, BMP180, BMP/E280 etc.

In this project we will use BMP280 / BME280 sensor.

BMP 280 :

BMP280 is a sophisticated sensor that very accurately measures barometric pressure and temperature with reasonable accuracy. The BME280 is the next-generation of sensors from Bosch, and is the upgrade to the BMP085/BMP180/BMP183 - with a low altitude noise of 0.25m and the same fast conversion time. The advantage of this sensor is that it can use either I2C or SPI for communication with microcontroller. For simple easy wiring, I will suggest to by I2C version board.

BME280 :

The new BME280 sensor, an environmental sensor with temperature, barometric pressure and humidity.The BME280 is the next-generation of sensors from Bosch, and is the upgrade to the BMP280.This precision sensor from Bosch is the best low-cost sensing solution for measuring humidity with ±3% accuracy, barometric pressure with ±1 hPa absolute accuracy, and temperature with ±1.0°C accuracy. It can be used in both I2C and SPI.

Note : BME280 can measure humidity but BMP280 can't. In market BMP280 is also available by the name of BME280. So be sure whether it is a BMP280 or BME280.