An absolute pressure sensor. There are special types for barometers, because of the accuracy needed mostly. An absolute gauge means one that measures against a vacuum, so the atmospheric pressure is seen. This would have a full scale a little over 1 bar. This link is an example:
http://www.vaisala.com/en/products/press...
The output of the example is 0-5V for the range from 500 to 1100 hPa. A hecto pascal is the same as a millibar. This voltage can be read by a digital voltmeter or a micro-controller, and converted to hPa for use elsewhere in some system. There are higher grades with better accuracy than the example.
Aneroid barometers and a mercury manometer are more traditional types using a mechanical pointer or visual readouts. These are both referenced to a vacuum too.
Hello Jorge :
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A barometer is used to measure atmospheric pressure.
The barometer may have a U-tube containing mercury with vacuum at one end and
the other end exposed to the atmospheric pressure. The difference in the mercury
levels should be about 760 mm.
There also exist aneroid barometers with a needle that points to a scale that
gives the atmospheric pressure.
NOTE : The barometric pressure given by the weatherman is not the actual barometric
pressure at the location; but is what atmospheric pressure would be if the location
were at sea level. I live at about 950 ft elevation above sea level and must subtract
1.0 inch of mercury from what the weatherman states.
Mercury column or aneroid barometer. Google each.
Use pressure gauge or vacuum gauge.
manometer i think
