RFID Phone Cases

Hello everyone.

My name is Ferib, and i am new to this forum.
I have been using Arduino for the past few months and started struggling with USB-C and Arduino.

The last few weeks i have been working on a RFID Phone Case.
Just to show off my idea, i made a amateuristic video about it, as you can see here:

My goal is to get rid of RFID Hotel Key cards or Sport Club cards.
So i don’t have to carry all those cards with me… Most people carry their phone with them every day so it might be a good idea to somehow merge the phone with the cards.

So i started drawing a phone case… the first result was bad and thick.
The only reason to make it that thick was for adding electronic components into it.

After a few more prototypes i finally made a “good” looking on, i haven’t printed it yet…
Here s a picture of the final result:

This looks like a regular phone case, but the bottom is just a bit longer with some micro controllers placed in it.
I have been using:

  • Attiny85 (Micro chip used for Arduino)
  • 100µ capacitor
  • L293D (Motor driver for the copper coil)
  • Copper Wire
  • USB-C male head

Seems like all those stuff fits inside the bottom part of the case.
But here comes the issue… i am using the USB-C to power the system.
But will it also be possible to transfer data to the chip?
So i can, lets say make a little Android app and store all my hotel key cards in it?
I am pretty sure i can store a few cards in the chip itself, but its a pain in the ass to reprogram the chip everytime i get a new key card.