This brand new digital currency (https://minepi.com/cakzxd) was developed by a group of Stanford University PhD's.
You can earn your own PI coins for free by simply downloading the (Pi Network) app from the Google Play Store or Apple App Store (search pi, or minepi, or pinetwork). It's FREE to download and earn coins on a daily basis.At the moment, to join the PI Network, an invite code is needed. You can join by using my invitation code (cakzxd).
It dose not draining your phone battery, And you even do not need to leave the APP open to mine, Pi does not affect your phone's performance, or use your network data.