7Semi BME280 Temperature, Humidity & Pressure Sensor Nano Breakout

Overview

The breakout is based on the Bosch BME280 environmental sensor, a 3-in-1 MEMS digital sensor that measures:

• Temperature

• Relative Humidity

• Barometric Pressure

It integrates all three sensing elements into a single compact chip, making it suitable for precise environmental monitoring.

Working Principle

The BME280 combines three different sensing mechanisms:

1. Temperature Sensor

• Based on bandgap temperature sensing

• Measures ambient temperature and provides compensation data for other sensors

2. Humidity Sensor

• Uses a capacitive sensing structure

• Absorbs moisture changes capacitance converted to digital signal

3. Pressure Sensor

• Uses a

• Air pressure deforms the diaphragm resistance change digital output

All three signals are processed internally and provided as calibrated digital outputs

Measurement Ranges

• Temperature: 40C to +85C

• Humidity: 0% to 100% RH

• Pressure: 300 hPa to 1100 hPa

Covers full environmental conditions from indoor to outdoor atmospheres.

Accuracy & Performance

Temperature

• Accuracy: 0.5C

Humidity

• Accuracy: 3% RH

• Response time: ~1 second

Pressure

• Absolute accuracy: ~1 hPa

• Very low noise enables fine altitude est>Supply voltage:

  • VDD: 1.71V to 3.6V

  • VDDIO: 1.2V to 3.6V

• Current consumption (typical):

  • ~1.8 A (Temp + Humidity)

  • ~2.8 A (Pressure + Temp)

  • ~3.6 A (all sensors active)

Very low power ideal for battery-powered systems.

Communication Interface

• I2C (up to ~3.4 MHz)

• SPI (3-wire / 4-wire)

Fully digital output no ADC required.

Internal Features

Factory Calibration

• Each sensor includes pre-calibrated coefficients

• No external calibration needed

Oversampling Control

• Adjustable resolution for:

  midity

Allows trade-off between:

• Accuracy

• Power consumption

Built-in IIR Filter

• Reduces:

  • Noise

  • Sudden environmental fluctuations

Multiple Power Modes

• Sleep mode (ultra-low power)

• Forced mode (single measurement)

• Normal mode (continuous measurement)

Altitude Estimation

• Derived from pressure readings

• Based on atmospheric pressure variation

Key point:

• Requires reference pressure (sea-level)

• Accuracy affected by weather changes

Physical Characteristics

• Sensor size: 2.5 2.5 0.93 mm (LGA package)

• Highly compact > ating Behavior

  • Fast response (~1 second for humidity)

  • Stable over temperature changes

  • Designed for long-term reliability and low drift

  Limitations

  • Measures relative humidity, not absolute moisture content

  • Pressure-based altitude depends on:

    • Weather variations

  • Sensitive to:

    • Condensation

    • Direct water exposure

  • Cannot detect gas composition (unlike gas sensors)

  Breakout Board Role (7Semi Nano Version)

  The nano breakout board:

  • Provides compact pin spacing for embedded designs

  • Exposes:

    • Power pins

    • I2C/SPI communication lines

  • May include:

    • Pull-up resistors

    • Basic sigul>

    Its purpose is easy integration, not altering sensor functionality.

    Summary

    The 7Semi BME280 Nano Breakout is a compact, high-accuracy environmental sensing solution that:

    • Measures temperature, humidity, and pressure simultaneously

    • Uses MEMS + capacitive sensing technologies

    • Provides fully calibrated digital output

    • Offers very low power consumption

    • Supports flexible configuration for precision vs power trade-offs