Door lock system using RFID

Hi, I am a student and working on a project that needs to have 2 inputs(1 analog) and 3 outputs.
I choose to use RC522 RFID reader and an Arduino Uno to actuate a door lock controlled by a servo.
So for the inputs I have the RFID reader and outputs:2 leds, buzzer and a servo.

What can I use for the analog input to make the system efficient?

Thanks

Try using a light sensor of some type and turn the lights on when they get in range.

gilshultz:
Try using a light sensor of some type and turn the lights on when they get in range.

Thanks for answering!

So you saying to add a light sensor(photoresistor) that turns the lights on in the room when the tag is in range right?