USING ATMOSPHERIC PRESSURE ENSORS IN WIRELESS APPLICATIONS

摘要

Barometric air pressure is an important meteorological parameter, playing a key role in weather forecasting. Equally, air pressure is an important parameter in calculating the air-fuel ratio in automotive applications for controlling and optimizing engine efficiency. Car manufacturers are always interested in using low-cost, high-accuracy and yet time-reliable sensors in their designs to increase fuel efficiency. The output of a barometric pressure sensor is measured in inHg (inches mercury) or hPa (mbar), or both. Typical ranges are 16-32inHg or 550-noohPa. The SI derived unit of pressure is the Pascal. One Pascal is equivalent to 0.01mbar (1/1000th of a bar), or to 0.000295 inches of mercury, and 100 Pascals (a hectopascal) is equivalent to one millibar (mbar). InHg is not an SI unit and is still widely used in barometric weather reports and aviation in some countries. It is defined as the pressure exerted by a column of mercury one inch in height at o°C at the standard acceleration of gravity.