Submitted to Flexible PCB Concept Contest. I would like to experiment with moving the sensor to different parts of the body similar to ideas presented in my ring-based heart rate monitor, my wrist-worn heart rate monitor, or my finger clip heart rate monitor projects also shared on Hackaday. Such prototypes would require flexible PCBs to properly match the body's contours to main the signal. I've even published a research article on one of my wrist-worn heart and respiratory rate wrist-worn heart and respiratory rate monitors (please feel free to message me for a PDF of the full article). The Flexible PCB Contest would help me take my project further and advance my study into body-worn sensors.