| 摘要 |
The apparatus measures the velocity of a moving object passing between two optical sensors by countering a time difference signals transmitted from the two optical sensors, installed in a distance, without using a microprocessor. The apparatus comprises: an optical detection start part(1) generating an active low signal according to an optical amount variation of the moving object at a detection start time; an optical detection finish part(2) generating an active low signal according to an optical amount variation of the moving object at a detection finish time; a time delay means(10) receiving an active low signal from the optical detection start part(1), and generating a reset signal after delaying a set time; a 1st signal latch(30) latching the active low signal for a time; a frequency divider(60) dividing by 1/100 the frequency resulted from an nand operation of the active low signal and 1Mhz oscillation signal generated from an oscillator(20); a 12 bit counter(50) counting the clocks from the frequency divider(60); a speed data generator(70); a speed displayer(70).
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