Carrying keys isn’t always convenient – you forget them, loose them well and nobody has a chance to enter without you near by. All these problems might be solved with keypad entry system. College students like this solution and do them a lot. So here it is one simple and pretty ‘messy’ solution if we can say so.
The brain role again is taken by Arduino Uno which reads keypad and drives stepper motor using motor driver board. Inside room electronics is placed in tin box with couple knobs that forse motor to open shaft when leaving. On the front of the door is another nicer box with keypad and power button. In order to enter code and activate system person has to turn power first and then enter code. This ensures that power is off when not needed.