BME280 Sensor accuracy

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akrueger
 
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Joined: Thu Jun 05, 2014 7:32 pm

BME280 Sensor accuracy

Post by akrueger »

Sensor:
https://www.adafruit.com/product/2652

I recently purchased 11 Adafruit BME280 sensors (product ID 2652) that I have hooked up to Pi Zeros via I2C. All of them are pretty consistent in their humidity readings (around 40% in my case), but that is nearly 10% lower than all of my other hygrometers (Accurite, ExTech, Temp Stick, and Google Nest Thermostat). I don't have a problem with putting an offset in my code per se, but I'm not familiar enough with RH detection to know if there are issues with non-linearity or not.
Other meters
Other meters
PXL_20210728_224132022.jpg (525.62 KiB) Viewed 74 times
Nest
Nest
PXL_20210728_224143967.jpg (410.72 KiB) Viewed 74 times
Is this much of a difference possibly a defect in these sensors, something else? Would an offset (even as high as 10%) be sufficient at higher and lower RH? At $15 a pop, I'm honestly a little disappointed to have this kind of disparity. I didn't see any natively supported calibration method when searching online.

Thanks

PS: The temperature values are also consistently about 8 degrees (F) high; I think I read that this sensor uses the temp sensor to inform the humidity. Could that be related?

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adafruit_support_bill
 
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Joined: Sat Feb 07, 2009 10:11 am

Re: BME280 Sensor accuracy

Post by adafruit_support_bill »

Temperature and relative humidity are definitely related. The most important property of a sensor is repeatability. If you have a suitable reference to calibrate against, accuracy is attainable via calibration: https://learn.adafruit.com/calibrating-sensors

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