ESP8266 Community Forum

- Mon Jan 16, 2017 2:21 pm #61109 I do have the BME280 working with the Adafruit_BME library. (See above)
With the BMP180 there was a difference between pressure at sealevel and pressure corrected at the current altitude.
At BME there is only pressure for sealevel and uses this for calculating the Altitude by:

Code: Select allSEALEVELPRESSURE_HPA = bme.readPressure() / 100.0F;
Alt = bme.readAltitude(SEALEVELPRESSURE_HPA);

How do I make a conversion to local pressure?
I suggest by using the Alt somehow?

Beside this I'm using pins 4 and 5 instead of pins 0 and 2 (They are allready in use).
It is be advised to use pull up's. I don't, but it is still working.
Why pull ups still needed?
Please advise

- Mon Jan 16, 2017 4:14 pm #61112 some breakout boards have pullups others don't.
If it's working then it's probably ok.

sensor allways measures pressure at location. normalized pressure (refrenced at sealevel) can only be exactly calculated with additional reference information or crudely estimated.

It's the same for sealevel from local pressure.

detailed article in german:
https://www.mikrocontroller.net/topic/415860#4851121

some background in english
http://lukemweather.blogspot.co.at/2013 ... ribly.html

- Mon Jan 16, 2017 4:29 pm #61113 Thank you for the clear answers.