The Story beganns with Pressy that was crowdfounded Project,
Xiaomi has just copied this and calls this Mikey.
The idea about this is very cool, most People don't use the Headphone jack but with Mikey or Pressy you do two things ad once! You have a free program able Button that you can use as you like and it's a dust cover for your headphone jack.
So you can program this button as a camera-, torchlight-, musik-button, and so on...
and the best thing about, this it's very cheap!
And you don't need the Original ,
(in Germany you can get one on ebay about 3-5€)
Just have look @ebay and search for mikey or Pressy ;)
Here you can Download the app:
Original App thread: