Hi, thank you for taking the time to read my post and any advice you can provide will be greatly appreciated.
I used an Arduino as part of my studies, over 10 years ago and have not touched one since. But I enjoyed using it and it may help with an issue I have.
I am looking for a way to restrict access to a room. Basically lone workers are not allowed in a production area. I want some lights to show red when no one is in the room and then the light will go green once two people have clocked in, so to speak.
I have been looking at RFID and the RC522. not I can probably blunder myself through the code, with a bit of hard work and some on the codes/tutorials online. One thing I find confusing is whether each individual card requires its own card reader. If you buy a kit, it seems to have multiple cards and their own readers.
Can I just use one reader and say for example, 20 cards?
I apologise if this is a really basic question.