How to detect hardware keyloggers?

This threat is not new and there are many software solutions to detect and eliminate these threats, even some antivirus have also begun to add modules and signatures in their suites to detect the most popular keyloggers.

But there is another type of keyloggers that in theory can not be detected by anti-keyloggers or anti-viruses, since they capture the information directly from the keyboard, these keyloggers are called Hardware Keyloggers and there are many types, to name a few I leave you the following list:

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