The sensor includes {HEAD ~ a light source transmitter} and {TAIL ~ a receiver} sensitive to the radiation emitted by the transmitter to be located on a diametrically opposite surface area portion of the body protruding part 
The sensor includes { HEAD ~ a light source transmitter } and { TAIL ~ a receiver } sensitive to the radiation emitted by the transmitter to be located on a diametrically opposite surface area portion of the body protruding part
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH