In article ,
  wrote:
>I have tried different tutorials and forums where people had same/similar
issues with i2c but still, I can't
>solve this problem.
>
>I tried two different BMP180 Digital Barometric Pressure Sensor modules and
even IIC/12C/TWI 1602 Serial LCD module
>
>None of them showed up on the i2c detect -y 1
>
>I have Raspberry PI 3 B and the following versions and Raspbian GNU/Linux 9
(stretch)
>
>https://forums.adafruit.com/download/file.php?id=55367

Check power on the sensor board itself with your multimeter. Then
(assuming that's all OK at 3.3v) check the SCL and SDA wires - swap
them over - it won't hurt anything, but it's easy to get these the wrong
way round.

Try one device at a time too.

Gordon

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