I want to make a food dispenser for my cat which only dispenses food for my own cat. My cat has a rfid chip and I want to use that to identify him. I already have a rfid reader: https://www.amazon.com/gp/product/B07WGX9WRW/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1. However I'm not sure where I need to connect the TXD pin to my Arduino uno. I also don't know how to code this. I first want a code to just read the rfid chip of my cat. Can someone help me with this?
It has a TXD wire so that implies serial communication. On the UNO you only have one hardware Serial port (Serial) and that is used to send text to SerialMonitor on a PC so you should probably use SoftwareSerial. Read about it in the menu item Help->Reference.