I am trying this device and I actually can’t understand the physical principle underlying the motion recognition by the photoreflectors. I really appreciate if you will be able to provide some scientific paper/document/book describing how the signal changes after a movement and what is actually measured.
Is the intensity of the radiation which is reflected back by the skin? If this was the case, I expect that the deformation of the skin’s surface will reflect the light in multiple directions, so a change can be noticed.
Is the attenuation of the light that travels through the skin, reaches the muscles and then comes back? So my guess is that the change in the signal is provided by the change in the configuration of the muscle’s fibers right under the skin.
I’d be very happy if you are able to clarify my dubts and I’ll also enjoy discuss with you, if you, like me, have just a theory and do not know the principle.