Photo Illustration by Kelly Caminero / The Daily Beast / GettyRemember the 1990s when mood rings were having a moment? Well, what’s old is new again, except with a high-tech twist: Instead of color-changing stones to indicate shifting emotions, today’s “modern mood rings” use physiological data to flag moments of stress, excitement, despair, and more.You might even be wearing one right now: They may be literal rings, like the upcoming Happy Ring, watches like the Fitbit Sense 2 or Upmood, or wri