I am making them through a bit different way of the "usual mining" I am actually "working" or call it whatever you want on a site called Steemit, which is mostly about writing articles. I am earning STD (steem dollars) within each article, and then I process the redeeming to bitcoins.
But this is not passive, and not guaranteed cuz there are days that I am not earning anything.. It all depends on "voting power" - who votes for you. Oh forgot to say votes are important because that's what earns your steem dollars. Steem dollars can easily be exchanged for bitcoins. The process takes 5-10 minutes.
So, what about you guys? What's your "passive income", how are you mining bitcoins?