In a previous post I wrote about tests of the BMP180 pressure sensor. These were not all I hoped for, so I ordered a BMP280 sensor, which is supposedly an upgrade of the BMP180. Perhaps it would give me better results.
As it turns out, it appears it does! I only ordered one sensor at this time, so I have not done any comparisons between different BMP280’s. But the first result was very encouraging. When I compare to the available official measurements by the KNMI, the output seems to be spot on.
For example, my weather station is located somewhere between the KNMI stations of Eelde and Hoogeveen. Checking the pressure observations for December 10th at 14:20, both Eelde and Hoogeveen give 1007.0 hPa. Meteodrenthe reported 1007.1 at that time. If the two KNMI stations deviate, the BMP280 shows a result somewhere in between. Bottom line, without any further calibration, the sensor results are accurate.
So, last week I decided to make the BMP280 my primary sensor. In addition, I’ve calibrated the BMP180 with a value of +0.6. This is roughly the difference between the two.
In terms of calibration, I will add the side note that I am taking the values from the sensor as is. There is this whole debate about relative versus absolute pressure. Considering I’m at about 15 meters above sea level, I’d have to add about 2 hPa (roughly 1 hPa per 8 meters) to get to a reading relative to sea level. It is unclear to me, and I have not been able to get any info on this, whether the KNMI readings are absolute readings or not. If the KNMI readings are relative to sea level, my sensor would be off quite a bit. I decided not to care about that. 🙂