Alternatively the sensor includes {HEAD ~ a bar code reader} that reads {TAIL ~ a code} on, for example, the spool of wire, an analog proximity detector, a plurality of proximity detectors, and a displacement sensor 
Alternatively the sensor includes { HEAD ~ a bar code reader } that reads { TAIL ~ a code } on , for example , the spool of wire , an analog proximity detector , a plurality of proximity detectors , and a displacement sensor
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL 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 OTH OTH