> The flexible circuits then would be removed and stuck onto a person. With the help of a smartphone app, medical professionals or patients could get readings and track progress over time.

1) Draw a circle

2) Draw the rest of the owl

/s

Indeed the pictures are not representative of the real setup. Anyway the idea is clever. The paper provides an overview about most of the missing bits, such as the mcu, power source, and software.

One of the applications is as an alternative electrode for ECG's. You'd attach a line from that sensor to an ECG machine (sorry, not an expert, so apologies for the imprecise terminology) and get similar results to using commercial electrodes.

I dunno if that makes it a sensor, technically, or just one component in a more complex sensor apparatus.