Riva Health wants to turn your smartphone into a blood pressure monitor A scientist and the co-founder of Siri raise millions for a stealthy digital health startup Riva Health, founded by scientist Tuhin Sinha and Siri co-founder Dag Kittlaus, wants to help people measure their blood pressure in a clinically approved way. Blood pressure can help indicate at-risk patients before they are actually at risk, showing early signs of heart disease. While other hardware solutions on the market promise the same end goal, Riva wants to be a purely software solution that integrates with hardware that it thinks its end user has anyway: their smartphone.