| 摘要 |
Operation of an electric microswitch 14 for timing or other purposes during rowing is brought about by the rower moving the heels 8 of his/her shoes 3 in opposite sideways directions transitorily. A unit 10 containing the switch 14 involves two plates 19,20 that are tied by cords 11 to the two heels 8 respectively within the foot-well 6 of the boat, so as to slide relative to one another against a spring bias when the heels 8 move apart. The microswitch 14 operates in response to the sliding to energize an LED 16 for sending a light pulse via fibre-optic cable 23 to a timing unit 24 . A modified unit 10 includes a wireless transmitter 25 in place of the LED 16 , and an alternative modification involves two parallel fibre-optic cables 26,27 from the unit 24 and an optical block 32 . The block 32 is moved in response to the heel-movement from where light transmitted by the unit 24 down the cable 26 is not reflected back via the cable 27 , to where the light is reflected back up the cable 27 from reflective surfaces 36,37 of block 32 . Light reflected back to the unit 24 via the cable 27.
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