Fig 5. Exercise with the S-CRP on an iPhone.

(a) shifting to the main exercise stage with voice guidance: “It is time to do the main exercise,” (b) measuring HR with voice guidance: “Please place your fingertip on the camera to estimate your heart rate,” (c) providing guidance on the exercise intensity with voice guidance: “Your heart rate is high. Please slow down,” and (d) detecting motion artifacts: “Your measured pulse is of low quality. Please place your fingertip on the camera again.”