BMP180 Barometric pressure sensor - deviates about 8 full points from expected

R.Wieser · 2020-06-30T17:11:11+00:00

Hello all, I've bought a BMP180 barometric pressure sensor and used an existing implementation of the conversion formule (as in the PDF mentioned below) to see it work. The problem is that the air pressure result is (currently) about 8 full points off from what I could find on the 'Web that it should be. The resulting temperature is in the middle of two other (though not as precise) thermometers, and therefore looks to be ok. I've made sure that the calculation is correct by taking the calibration, UT and UP values straight from the PDF here: pull them thru the calculation and getting the exact intermediate results as well as T and P values back as shown in the PDF. My question: Is the sensor supposed to be able to give that different results (internet shows 1008, 1009 hPa around my position, the sensor shows 1000.47) ? I thought that the calibration process and resulting data would not allow for it ? What might be causing it ? Regards, Rudy Wieser

Jun 30, 2020 22 Replies

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Kees Nuyt 6 years ago

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Regards, Kees Nuyt

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Bob Martin 6 years ago

Have you checked with Google Earth for altitudes?

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druck 6 years ago

I've found this is the most accurate way of getting the height of your location, far more accurate than (non differential) GPS altitude.

My BME280 seems to be about 4mb out when corrected for altitude and compared to Met Office sea level readings. It also differs from the pressure read from my Oregon Scientific Bluetooth Weather station in a non linear way (the same at low pressures and up to 2mb lower at higher pressures).

But I treat it the same as the temperature readings, forget the absolute values, just look at the trends.

---druck

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