BME280 temperature too high

[dr-ni]

is my sensor broken or is the firmware not measuring correct?

arendst/Tasmota#1051 (comment)

[dr-ni]

[ricki-z]

Please check how the BME280 is positioned in the housing. The electronics generate heat that accumulates in the upper area. So try to mount the BME280 as near as possible on an opening.

[dr-ni]

I'll try next week...
But can the method above help to reduce the temperature?
I'm also searching the reason why dht22 humidity always is 99.9%

[ricki-z]

The high humidity values are a known problem with the DHT22 when used outdoors. Its some kind of saturation.
This is also a reason why we switched to the BME280.
There are many BME280 in our network, especially in Bulgaria. We haven't heard about this problem with our firmware before. As we started using the BME280 we had a similar problem and switched to the recommended settings for the BME280 when used as a "wather station".

[dr-ni]

ah ok, so this is not helping a long time?

https://forum.arduino.cc/t/arduino-uno-dht22-humidity-99-9/225361/15

[ricki-z]

As you can see in the article the humidity is going up again to 99% when the sensor is cooling down. So the problem isn't really solved by this. And having around 50 °C all the time wouls be replacing one problem with another ...

[AnDrEaZaNoLeTtI]

I know that is an old topic... but I hope I can be useful to anyone who has the same problem of sensor overheating...

I recently created a humidity detection node using an ESP8266 and a BME280 and I ran into a problem of high temperature read by the sensor. my readings were 6-8 degrees higher than actual.

I read many forums that talked about self-heating problems and I resigned myself to using another sensor for temperature readings and using the BME280 only for humidity.

almost by chance I noticed that sometimes for a few seconds the readings of its sensors aligned and upon investigation I discovered that this happened when the wifi signal was lost.

i modify firmware in order to turn on/off wifi according with a input pin and i connect my laptop with esp8266 throw serial pin in order to read logs. I discovered that with wifi off the readings are close up to 0.1°C, with wifi on the error was 7°C.

the problem was the sensor being too close to the esp8266 antenna... I lengthened the wires to keep the sensor at least 15 cm away from the antenna and I no longer had problems with high temperature readings even with reading time of 10s... with much faster readings (1 s) there is still an overtemperature, but limited to around 1.5 °C