This one looks more "plausible" than some of his others. The MEMS gyroscope is considered a "safe" device on iOS and Android and can be accessed with Javascript.
I get that young male PhD students find spying on people fascinating. I used to be fascinated by it also, until I became a sys admin and learned that people are immeasurably boring. But why is this research being encouraged? Do we really need more ways to attack computers and data? It's already obvious they will never be secure.