I am currently using a HP206c grove pressure sensor and while it is on a table, not moving at all, in an office, I get huge variations of mesures (like 3m from one mesure to another…). I do not think that it is normal, as it is written “High Accuracy sensor” I would have thought of a few cm of variations.
I use the demo of the “Grove HP20x” library, downloaded from the Arduino IDE software, demo which is written by SeeedStudio.
The sensor is plugged on a Grove base Shield, connected to an Arduino Uno and plugged by USB on my PC.
The picture above is the original datasheet, which mentions “The higher DSR will normally achieve higher measuring precision, but consume more time and power”.
By default, we use a sensor output conversion with a DSR of 1024 in the program library. Grove_Barometer_HP20x/HP20x_dev.cpp at master · Seeed-Studio/Grove_Barometer_HP20x (github.com)
So if you want to improve the accuracy, try changing OSR_CFG to HP20X_CONVERT_OSR4096 and then change OSR_ConvertTime to a time greater than 131.1ms.