Bosch – BME280 Integrated Environmental Unit
The BME280 is an integrated environmental sensor developed specifically for mobile applications where size and low power consumption are key design constraints.
The unit combines individual high linearity, high accuracy sensors for pressure, humidity and temperature in an 8-pin metal-lid 2.5 x 2.5 x 0.93 mm3 LGA package, designed for low current consumption (3.6 μA @1Hz), long term stability and high EMC robustness. The humidity sensor features an extremely fast response time which supports performance requirements for emerging applications such as context awareness, and high accuracy over a wide temperature range. The pressure sensor is an absolute barometric pressure sensor with features exceptionally high accuracy and resolution at very low noise. The integrated temperature sensor has been optimized for very low noise and high resolution. It is primarily used for temperature compensation of the pressure and humidity sensors, and can also be used for estimating ambient temperature. The BME280 supports a full suite of operating modes which provides the flexibility to optimize the device for power consumption, resolution and filter performance.
BME280 target applications
- Context awareness, e.g. skin detection, room change detection
- Health monitoring / well-being
‒ Warning regarding dehydration or heat stroke
‒ Measurement of lung volume and air flow - Home automation control
‒ Control heating, ventilation, air conditioning
(HVAC) - Internet of things
- GPS enhancement (e.g. time-to-first-fix improvement,
dead reckoning, slope detection) - Indoor navigation (change of floor detection, elevator
detection) - Outdoor navigation, leisure and sports applications
- Weather forecast
- Vertical velocity indication (rise/sink speed)
Technology and specification
Emerging applications such as indoor navigation, home automation control, personalized weather stations and innovative sport and fitness tools require a pressure sensor with high relative accuracy and a low TCO, in combination with fast response, high accuracy relative humidity and ambient tempera-ture measurements.
The BME280 is perfectly suitable for such applications as the device features excellent relative accuracy of ±0.12 hPa (equivalent to ±1 m difference in altitude), and an offset temperature coefficient (TCO) of only 1.5 Pa/K (equivalent to 12.6cm/K).
Sensor operation
The BME280 supports I2C and SPI (3-wire/4-wire) digital, serial interfaces. The sensor can be operated in three power modes: Sleep mode, normal mode and the forced mode. In normal mode the sensor automatically cycles between a measurement and a standby period. This mode is recommended when using BME280 built-in IIR filter when short-term disturbances (e.g. blowing into the sensor) need to be filtered. In forced mode, the sensor performs a single measurement on request and returns to sleep mode afterwards. This mode is recommended for applications which require low sampling rate or host-based synchronization. In order to tailor data rate, noise, response time and current consumption to the needs of the user, a variety of oversampling modes, filter modes and data rates can be selected. In combination with several short term disturbance filter settings, the sensor can be programmed in a very flexible way in order to adapt to application and power management requirements. To simplify the design-in phase, default settings optimized for several example use-cases such as weather monitoring, elevator / stair case detection, drop detection or indoor-navigation are provided.
System compatibility
The BME280 has been designed for best possible fit into modern mobile consumer electronics devices. Besides the ultra-small footprint and very low power
consump¬tion, the BME280 has very wide ranges for VDD and VDDIO supply voltages Bosch is the world market leader in MEMS sensors.The BME280 combines this extensive experience and reliability for consumer applications. Bosch Sensortec is a subsidiary of Bosch that focuses on micromechanical components for the non-automotive markets.
