Lock system + access register

Projects General Guidance
1

Hi everyone!

First off all, i apologize for my english..

I'm fairly able when it comes to assembling the Arduino and kinda able to understand a C++ code, but i have no idea how to write one =/

Well, i'm trying to make a system with the Arduino UNO that works like this:

There's a door (or anything else with a lock) with a numerical key pad (0 - 9 digits) where only autorized personel can open.
They will be able to register their own password (6 digits max). everytime someone uses said password and unlock the door, the system will register the time and the user that unlocked it.

I searched for similar projects and found some, but there's a catch, i would like to do said project using a USB numpad instead of those you buy for the arduino. Also, if possible, i would like to use the arduino serial to show the access to said lock.

The hardware part is preety simple:

A RGB LED (or 2 simple LED's, green and red)
Red means locked, green unlocked

A buzzer that emits a single short bip everytime a key is pressed and 2 bips that confirm a correct password

i'm basing my project on this one:

Thanks in advance gentleman

2

AugustoGaddini:
there's a catch, i would like to do said project using a USB numpad instead of those you buy for the arduino.

That will make things more complicated. You will need a USB Host Shield or equivalent just to get digits from the keypad.