Imac USB Port Assignment - Master and Slave I2C

Hi,

I hope I'm in the right section of the forum for my question, if not Please redirect me.

I connect 2 Arduino Unos to 2 different USB ports on my Imac to try this tutorial :

It works once, then when I disconnect and reconnect the arduinos the USB port assignment
messes up. i.e. I get both arduinos on the same port. Changing ports manually will not work either.

How do I solve this problem ?

It works once, then when I disconnect and reconnect the arduinos the USB port assignment
messes up. i.e. I get both arduinos on the same port. Changing ports manually will not work either.

If you disconnect the Arduinos, quit the IDE and start it again after you reconnected the Arduinos. The port mess is a problem of your Mac, the port assignment is handled by the OS.