BME280 Humidity Pressure Temperature Sensors

The APSM (Advanced Porous Silicon Membrane) BME280 is a sophisticated digital composite sensor designed to measure ambient temperature, humidity, and atmospheric pressure with an emphasis on low power consumption. This sensor is an evolution of the BMP280, sharing similar operational principles but with the added capability of humidity sensing.

Sensor Features and Capabilities

Measurement Capabilities

• Temperature:

1. Range: 0°C to 65°C
2. Accuracy: ±0.5°C max, ±1°C typical
3. Resolution: 0.1°C

• Humidity:

1. Range: 0% to 100% Relative Humidity (RH)
2. Accuracy: ±2% RH
3. Response Time: Greater than 1 second
4. Hysteresis: ±1% RH
5. Resolution: 0.8% RH

• Barometric Pressure:

1. Range: 300 to 1100 hPa
2. Accuracy: ±1 hPa
3. Resolution: 0.18 Pa

Sensor Elements

• Humidity-Sensitive Element:

Offers fast wake-up and response times, ensuring quick adaptation to changes in the environment.

Features high accuracy over a wide operating temperature range.

• Barometric Pressure-Sensitive Element:

Known for low noise, high precision, and high resolution, making it ideal for applications requiring accurate atmospheric pressure measurements.

• Temperature Sensing Components:

Characterized by low noise and high resolution, these components provide temperature-compensated self-correction for both humidity and pressure measurements.

Power and Interface

• Operating Voltage:

1. BME280: 1.7 to 3.6V DC
2. BMP280: 5V DC (Note: BME280 is designed for lower voltage operation)

• Digital Interface:

1. IIC: Supports up to 3.4MHz in slave mode.
2. SPI: 3-wire or 4-wire slave mode at 10MHz.

Design and Compatibility

• Compatibility:

Fully compatible with the BMP280, ensuring seamless integration in systems designed for the BMP280.

• Operational Principles:

Follows the same control and data readout principles as the BMP280 for temperature and pressure, with added humidity functionality.

• Configuration:

The humidity and pressure elements can be independently enabled or disabled via the sampling rate register, offering flexibility in power management and functionality.

Applications

• Consumer Electronics: Ideal for space-limited devices like smartphones, tablets, smartwatches, and other wearables.
• Environmental Monitoring: Suitable for weather forecasting, indoor/outdoor navigation, and smart home devices.
• Aviation: Utilized in flight control devices and vertical speed indication due to its precise pressure sensing capabilities.

Physical Specifications

• Dimensions: 15.4mm (L) x 11.6mm (W) x 2.4mm (H)
• Mounting: Features M3 fixing screw holes for easy installation and secure fixing in various applications.

Pin Description

• VCC: Power Positive (1.7 to 3.6V for BME280)
• GND: Ground
• SCL: I2C/SPI serial clock line
• SDA: I2C serial data line
• SDI: 3-wire SPI serial data input/output ports
• SDO: 4-wire SPI serial data output port / I2C address select bit
• CSB: Chip select pin; high level (default) for I2C communication, low level for SPI

Instruction for Use

I2C Mode Configuration

• I2C Address Selection: The device address is determined by the SDO pin:

1. Low Level (GND): Slave address is 1110110 (0x76)
2. High Level (VCC): Slave address is 1110111 (0x77)

This configuration allows for flexible integration into systems with multiple I2C devices.

Conclusion

The APSM BME280 sensor combines precision, low power consumption, and versatility, making it an excellent choice for a wide array of applications in IoT, consumer electronics, environmental monitoring, and beyond. Its ability to measure multiple environmental parameters with high accuracy and its compatibility with existing BMP280 designs make it a valuable tool for developers and engineers looking to enhance their products with environmental sensing capabilities.