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Bar02 Sensor Reading incorrectly


(Nicholas Waterton) #1

About 5 months ago I built a tank depth sensor using your Bar02 pressure sensor, with a BME280 to read atmospheric pressure.

This has worked perfectly for measuring the water depth in my tank, which is 20cm deep.

Last week the Bar02 failed (shorted the i2c bus).

I ordered a new Bar02, and covered all the connections (including the rear, but obviously not the front) on the new sensor with silicone (just in case the previous failure was due to leakage).

With the new sensor, in air I am reading 1031hPa, all my other barometric sensors (I have 4 scattered about) read 997hPa +/- 2.

The reading does go up when submerged, but not as much as I would expect.

I am not sure if this is an offset, or a calibration factor problem, but it’s throwing my water depth measurements off by 30cm in a 20cm tank.

Do I have a bad sensor? The previous Bar02 read exactly the same as all my other barometric sensors in air, and 1hPa per cm of water in the tank, all I had to do was subtract atmospheric pressure, and presto! Very accurate depth reading.

I don’t want to jimmy my program around if the sensor is faulty.

Thanks.


(Jacob) #2

This offset is normal, see here: