I just had an idea for another module to add to our control panel, on the center module. It is very simple, and does not require very much in terms of wiring and hardware, which is why I like it.
Enter the RC522 RFID Reader. I found this while digging around in my Arduino kits, and I remembered a computer unlocker project I had seen some time ago using one of these. The principle is, you swipe the card/dongle/RFID chip thing and it unlocks your computer. Cool. But we can make it better.
My idea is to use a similar setup, except with a small tray/slot for the card or dongle to sit in. Then, we have two buttons next to this slot. Press either button, and the Arduino will check to see if the proper card is in the slot. If it is, it will either enter the password and unlock the computer, or it will lock the computer, depending on which button was pressed. If neither button is pressed, nothing will happen, so you can leave the card there for the duration of your computer use, then use it to lock the computer and remove it.