There’s an Infrared Detector for the iPhone somewhere on the internet.
I think you're on to something. Imagine having a wrist device that can sense changes in a woman you're flirting with. Sort of a mood ring on steroids.
If you don't know what that is, back in the 1960s and 1970s people wore them and they changed color depending on the heat they sensed. Blue bad, but warm red good. It was a conversation starter between couples.
Additionally, the wrist device gives you feedback through your skin. A Woody Allen movie "Sleeper" in 1973 had a guy awaken in the future, and a gal gave him an orb to play with between them in lieu of sex. A wild feedback device for him. Anyway, I'm postulating effects way beyond simple heat detection. More of an electronic love potion. Ha-ha, my mind wanders when I'm tired at night!