Is it safe to use RFID in a phone case [closed]

Question

I looked into this and found only vague indications that it should be no problem, but nothing specific enough to feel safe.

Based on reading this question and its answers and comments it seems like it would be fine, Can an iphone/android cell phone communicate with RFID?

But for my actual question.

I am wondering if it is safe to keep a RFID card in the back of a cellphone case (pressed right against the phones back) and to keep it in the case while using both the phone and the card.

I keep my iPhone 6S in a drop-case and want to put my door's RFID proximity card in the back of the case so I don't have to carry an additional card when my phone is typically in my hand.

I have read that RFID chips are passive so it won't hurt anything carrying it around, my worry is since it will stay in the back of the phone case when I scan it will that transmission cause any issues? I can't see any reason why I would, but I would rather not fry a multi-hundred dollar IPhone on my understanding without asking someone more knowledgeable.

My specific use case is a home-made Arduino RFID automatic door lock, easier to buy something else, certainly, but not nearly as much fun as building one and learning along the way.

Answer 1

It will be fine. RFID tags are passive, as you say. An RFID reader can identify and read different tags within its detection field, not just one.

Besides having worked with RFID, I have three door-entry RFID tags on a small keyring. When each is detected, the others are clearly within the detection field and its never caused a problem.

Answer 2

Wrong, I put an RFID card holder on the back of my phone, and it causes the screen to go blank. As soon as i take it off, the screen comes back. So, YES the can cause issues with your phone.