"PS: my BME280 is working like a charm."
Care to share details?

Sorry you feel this way - thanks for trying but you didn't solve my problem. Best that I can tell from internet searching is a rather laborious process of running an Arduino simulation on the PI and converting the BME280test.ino to run on the PI (https://robidouille.wordpress.com/2013/12/26/installi...

Doesn't work -

Anyone else?

Yes I've followed their instructions, ambiguous though they are - e.g., " run the following command from this folder:
python Adafruit_BME280_Example.py". The folder is never specified hence I've tried many possibilities and none work.

Did the download, installed the unzipped files. Ran the program in the installed directory/sub-directories. Same error. Do you actually have this working? If so what is your directory structure and content that contains the working Adafruit_BME280_Example.py?

I'm trying to run a BME280 (IC2) on a PI3. The IC2 connection checks out so hardware looks ok. Attempting to run the Arduino eample: #!/usr/bin/python from Adafruit_BME280 import * sensor = BME280(mode=BME280_OSAMPLE_8) degrees = sensor.read_temperature() pascals = sensor.read_pressure() hectopascal...

Correct - it's a three pin IC from Dallas Maxim.

Sorry, you misunderstood. I was setting up a test for non-parasitic use but had a parasitic only device from a old one-wire system.

Problem solved - wrong DS18B20 (PAR version) which only works in parasitic ("true" 1-wire) mode. All works now as it should.

Just checked the specs for the DS18B20 - "The power-on reset value of the temperature register is +85°C". It's clearly not getting the correct 1-wire signal from the PI. Wiring problem? Will check it out later today.

I have a problem with my GPIO reading any of several DSB20 much too high - a constant 85 deg. C. The device isn't even warm to the touch. Any clues?