olf2012:
There is no Mac without USB since 1999. Are you sure there is no USB port?
I have USB-C...
DrAzzy:
Why can't you plug the arduino board into the mac? You can use an inexpensive USB hub to get more ports - all the macs in recent times have had USB...
I have a USB-C adaptor but I don't know. I justo want to use my mac without plug no more than external display 