Why do cash machines have metal keyboards?
Bank ATMs are generally metal numeric keypads, which have the benefit of preventing leaks.
Think about it: When you press a password with your finger, the temperature of the keyboard changes. If we take a photo with a thermal camera right after the transaction, we can get the password by looking at the photo.
The advantage of the metal keyboard is that the metal conductivity is high, and the temperature changes particularly fast. Even if someone takes a picture with a thermal camera, it’s hard to see the color order.
Have you ever wondered what the little cylindrical objects on your power cord, mouse, keyboard, laptop, printer, etc. are for and why they exist?
Yes, this little object was put there on purpose. These “bumps” are called ferrite magnetic beads or ferrite chokes, and their sole purpose is to reduce electromagnetic interference and radio frequency interference.
Simply put, it is used to reduce unnecessary signals or noise.
As we all know, when two electromagnetic devices are connected through a cable, the cable acts as an antenna. The problem is that, like all antennas, these cables can also pick up and transmit signals from unrelated devices. The result is noise or interference with unwanted signals.
This is the necessity of ferrite beads, which can eliminate the broadcast signal and ensure that the cable does not send any other interference signals that are not planned.
If you open up these bumps, you’ll find a solid cylinder made of ferrite, which itself is magnetic.
Ferrite is made of iron oxides (aka rust) combined with other metals. It is black, hard and brittle. But its magnetism can effectively eliminate interference.