Barometer

References

• https://www.infineon.com/dgdl/Infineon-AN+Choosing+the+right+pressure+sensor-AN-v01_00-EN.pdf?fileId=5546d46259b0420a0159cff8c1470876

• https://www.seeedstudio.com/blog/2019/12/30/what-is-barometric-pressure-sensor-and-arduino-guide-to-get-started

• https://www.rohm.com/electronics-basics/sensor/barometric-pressure-sensor

What does a barometer do? How do they work?

A barometric pressure sensor is used to measure the atmospheric pressure measurement in environments. The way the work is dependent on the type of sensor (of which there exists many), two of which are:

• Aneroid barometer

  • Consists of an aneroid cell

  • Aneroid cell expands/contracts when there small changes to atmospheric pressure

  • Movement from cell causes mechanical levers to amplify, resulting in display pointers to trigger and register as readings on the front display

• MEMS Barometric Pressure Sensor

  • Contains a diaphragm that’s formed through one capacitive plate that’s in contact with the atmosphere

  • Atmospheric pressure is detected through how much the diaphragm is deformed due to resulting pressure (higher pressure → more diaphragm moves → higher barometer)

What specs/metrics should you be looking at when you select a barometer?

• Operation range

  • Upper and lower limits of pressure the sensor can detect

  • Absolute accuracy

    • Combination of relative pressure error and offset error

    • Offset error can be removed with calibration

  • Relative accuracy

  • Noise in pressure

  • Long-term stability

    • Need to make periodic calibration to keep sensor accurate

    • Overtime, the sensor will get less accurate

  • Maximum Sampling Rate

  • Interface

  • Temperature Coefficient Offset