here is a youtube video (https://www.youtube.com/watch?v=8Vc-69M-UWk https://www.youtube.com/watch?v=8Vc-69M-UWk) from 2014 that demos the technique on pin pad

here is a youtube video (https://www.youtube.com/watch?v=8Vc-69M-UWk https://www.youtube.com/watch?v=8Vc-69M-UWk) from 2014 that demos the technique on pin pads and refers to the following paper https://cseweb.ucsd.edu/~kmowery/papers/thermal.pdf https://cseweb.ucsd.edu/~kmowery/papers/thermal.pdf