ubermick:
But the guesser says that the backpack has to be NOT connected to the LCD screen in order for it to work?
- hookup the i2c backpack and only the i2c backpack to the Arduino (make sure to use the needed pullup resistors - i2c needs them to work correctly)
Don is correct.
What I meant to say is that you should hook up your backpack with LCD attached
but don't hook up any other i2c devices on the i2c bus.
I see your concern. Sorry about the confusion. I'll update the wording to be clearer.