DHT22 vs SI7021 big RH % difference
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DHT22 vs SI7021 big RH % difference
Any idea why? Temperature is on par...
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Re: DHT22 vs SI7021 big RH % difference
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Re: DHT22 vs SI7021 big RH % difference
The difference cannot only be explained by the typical accuracy errors as mentioned in the datasheets of these sensors.
your combined error is about 13% which is more than worst case errors together.
DHT22 accuracy RH +/- 2% (max +/- 5%)
SI7021 accuracy RH +/- 3% max.
If both sensors are as good as new , you probably have at least one fake sensor. Try some more sensors and you can find out which one is out of specs.
If you have older sensors it can be normal to be out of specs.
The substrate inside the sensor which measures the RH is usually a sort of salt crystal which is susceptable to contamination and water. So when your sensor is outside and rain is reaching the inside of the sensor, after drying it is not accurate anymore.
your combined error is about 13% which is more than worst case errors together.
DHT22 accuracy RH +/- 2% (max +/- 5%)
SI7021 accuracy RH +/- 3% max.
If both sensors are as good as new , you probably have at least one fake sensor. Try some more sensors and you can find out which one is out of specs.
If you have older sensors it can be normal to be out of specs.
The substrate inside the sensor which measures the RH is usually a sort of salt crystal which is susceptable to contamination and water. So when your sensor is outside and rain is reaching the inside of the sensor, after drying it is not accurate anymore.
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