From Gizmodo:

A team of researchers at France’s Research Institute of Computer Science and Random Systems created an anti-malware system centered around a Raspberry Pi that scans devices for electromagnetic waves. As reported by Tom’s Hardware, the security device uses an oscilloscope (Picoscope 6407) and H-Field probe connected to a Raspberry Pi 2B to pick up abnormalities in specific electromagnetic waves emitted by computers that are under attack, a technique the researchers say is used to “obtain precise knowledge about malware type and identity.”