I found this recipe, but it doesn't work.
I put in either
http://plu.sr/feed.php?plusr=103156295300828440975, but I keep getting an error
Trigger field Not a valid feed url, missing feed title
It isn't working because the http://plu.sr site is down.
Try using a different Google+ RSS Feed provider such as http://googleplusrss.nodester.com
You just add you Google+ ID to the end of the URL - like this > http://googleplusrss.nodester.com/103156295300828440975