I see the rfid sachets for car keys, but do keys need to be fully encapsulated to block the signal from just 1 or 2 sides? For example could the wall the keys are stored on have something installed for blocking if the driveway is behind said wall?
In: Technology
There’s two types: passive and active.
Passive RFID blocking is what you’re describing, and how it works is that you simply surround the object in question with something that doesn’t let radio waves pass through it.
For passive protection, a conductor like Aluminum is used. When a radio wave hits it, it will bounce them back instead of letting them pass through. Put an aluminum cube over your WiFi router, and your WiFi signal will drop harder than the stock market in 1929, if it doesn’t just disappear entirely. This is called a Faraday Cage.
If you were in a room that was surrounded by a bunch of conductive metals, then yes, that would cause issues. You can experience this in real life. Ever been somewhere like a warehouse with a big metal roof? You might notice your cell phone signal is slow and weak unless you’re near a window or wall, even though if you went outside you could get full bars of 5G.
The other option is active protection. These work by broadcasting a different signal that interferes with the source signal. This requires some kind of microchip and antenna with a power supply. You find active RFID protection less in consumer goods and more in industrial products.
A brick wall has lots of gaps in the structure it is basically a solid sponge and radio frequencies can pass through it if the wall is small enough, basically why wifi will work in all rooms in a house. https://youtu.be/G19cVJfy24A
this video will teach you everything you would want to know about blocking rfid https://youtu.be/_X6DVQH0Js0
the tldw version is, an rfid/nfc chip is powered by the reader. the reader only sends out a limited amount of power, any large conductive object near the card will absorbe some of this power. absorb enough and the chip cant be powered enough to send. it does not matter if the conductive material encases the device or not so long as it can absorb enough power
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