Again and again, customers ask about the accuracy of the DHT 22 sensor. The data sheet says: "Temperature +/- 0.5°C" "Humidity +/- 2-5%" But what does this mean in practice? We did the work and compared it to 3 test setups. The DHTs are original Aosong modules. In this blog post we make the results available as a picture gallery.
In our first setup, we connected 4 different nanos to 4 different DHT modules, supplied them with 5V, and used the Adafruit DHT-sensor Libary. The result:
So we see the discrepancies. The measurements took place in our office, within a few minutes (lack of a climate chamber). All but a few values are within the tolerance of the datasheet.
We do the 2nd and 3rd test setup with ESPs, first with the Arduino Libray, then with the Libarys for ESPs in order to be able to measure the values as soon as possible. The DHTs are now supplied with 3.3V. Here is the result for our ESP8266 with Oled:
So we see that the values are close together here, we try the same again with our LoLin board:
And finally with our AmicaV2:
I think that way, everyone can simply decide for themselves whether the sensor is sufficient or suitable for their needs.
Until the next post ;)