Such a pass is also called a “tag”. Some of the most common RFID passes have an operating frequency of 125 kHz. The internal structure consists of a wire coil and a microchip.
Such a pass is certainly not large, but still carrying it every day with you is not so convenient. Yes, and if you forget, then returning home for a pass is not very pleasant.
I will show you a way to integrate a pass card into a cell phone.
So, take a pass and soak it in acetone for 1 hour. The main thing is not to overdo it, so that acetone corrodes only plastic, and not a coil with a chip. Take care of ventilation as acetone is very toxic. Keep the pass in acetone, in a container that closes so that excess fumes do not evaporate. And be sure to ventilate the room.
After an hour, gently bluish the plastic. And gently peel off the separated layers. Take out the coil with the chip.
The black point on the micro-board is a chip with information.
Next, take a cell phone. Remove the back cover.
We put the coil with the chip on the back wall. We coat with nail polish. We are waiting for drying. You can apply several layers.
All. Close the phone cover and check.
In principle, there is nothing complicated here. The main thing is not to overdo it with soaking acetone and do not break the wire when transporting from one place to another.
Now you do not need to carry a pass with you, and the phone will always be with you.
