The rig changes every three years: this time around, Hawking is using a Lenovo X200 tablet, custom-built with an Intel Core i7 processor and a webcam. There’s also an IR sensor hanging on Hawking’s glasses that reads the light coming off his cheek and translates it into speech, which comes out of an amplifier underneath his wheelchair. (via The Intel engineer behind Stephen Hawking’s computer | The Verge)