Hi
I have some DHT11 sensors.
When they are connected to a common circuit in a common place, they show different humidity values!
The difference in temperature values that they show are acceptable
But the humidity values showed are so different from each other!
What is the reason and what is the solution?
Welcome to the forum
According to the datasheet the sensors have a typical accuracy of +/- 4% of relative humidity
Please give some examples of the discrepancy
Those sensors are very cheap. You get what you pay for. I quit using DHT11 years ago in favor of the DHT22 (better) or BME280 (better yet). There are other humidity sensors, I just have no experience with them.
I have to agree with groundFungus on this. Accurate and repeatable humidity sensors do not come cheap. The accuracy is: Accuracy：25℃ ±5%RH. So if one is reading low 5% RH and one reading high 5% with a known RH of 50% a low of 45% and a high of 55% would be acceptable limits. That is a 10% RH difference.
If you want to make up a saturated salts slurry. A Google of saturated salts humidity calibration should get you started. Any small jar with a lid should work. Cut a hole in the lid allowing your sensors to rest above the solution making sure you do not short any of the leads. A slurry of common table salt will do as a starter.
Less getting fancy a Google of wet bulb dry bulb humidity which should give you the actual humidity.
With a known you can calibrate your sensors using your software.
The classic a man with two watches never knows the correct time. That applies.
Ron
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