The reader emits radio waves in the range of 2.5 cm to 20 meters or more, depending upon its power output and the radio frequency used.
When an RFID tag passes through the electromagnetic zone, it detects the reader’s activation signal.
The reader decodes the data encoded in the tag’s integrated circuit (silicon chip) and communicates to the host computer for processing. Before issuing, each card is assigned with a number. Issued customer details are then loaded in the computer..
The microcontroller then checks for the received tag details with already stored details and checks for authenticity of the card and can allow free Entry / Exit.