Israeli-based researchers team managed to do it with cheap consumer-grade components as well as small enough to hide inside a piece of pita bread. Using cheap equipment, the team of researchers, including Daniel Genkin, Lev Pachmanov, Itamar Pipman and Eran Tromer, was able to capture keystrokes, applications running on a computer system, and encryption keys. The researchers say they were able to crunch the data and get the password in a matter of few seconds.
Source: https://thehackernews.com/2015/06/how-to-hack-computers.html