Long gone are the days when people used to stand and wait in long checkout lines at the grocery store. Thanks to the Radio Frequency IDentification (RFID) technology. With this RFID based walk-through automatic checkout solution, you can fill up your cart and walk right out the door. No longer will you have to wait as someone rings up each item in your cart one at a time. Instead, the RFID tags attached to items will communicate with RFID reader that will detect every item in the cart and ring each up almost instantly.
For most of our RFID based Arduino projects, RC522 RFID Reader/Writer module is a great choice. It is low power, low cost, pretty rugged, easy to interface with and insanely popular among hobbyists.