PasswordKeeper on Aruino Pro Micro or why keep it simple when elaborate way exists!

It seems, that the main problem with microcontrollers for fan of electronics (especially beginners) is to find out where to apply them :) Nowaday electronics, especially digital one, is more and more looks like a black magic. Only 80-Lvl wisards are able to do something there with tiny components. That is a reason why Arduino boards become very popular. They encapsulate black magic and some smoke ;) into board with human-manageable pins. This post I want to devote to a fairly simple project, named PasswordKeeper, on the base of Aruino Pro Micro board. This board hosted ATmega32U4 chip.”