The detector includes a microswitch having {HEAD ~ a sensing arm} which contacts a center portion of {TAIL ~ an elastic membrane} 
The detector includes a microswitch having { HEAD ~ a sensing arm } which contacts a center portion of { TAIL ~ an elastic membrane }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL