ENTRY DETECTION INPUT DEVICE

摘要

PROBLEM TO BE SOLVED: To easily transmit a signal making an operator who operates a device in a closed cabin to recognize an entering person alone by cutting the DC component of an input signal and extracting only the AC component, and shaping it into pulses and deciding the pulse width and period. SOLUTION: When flash light 3 as an entry detection output is inputted to one of five photodiodes 1a to 1e, a capacitor C detects its pulse change and cuts the DC component to extract only AC component. Then the component is integrated by a resistance R1 and a capacitor C2 and then shape it into pulses. The ON/OFF state of the pulse signal shaped by the pulse shaping means 21 is sent to a U counter and a D counter and a pulse width detecting means 22 (CPU) which detects the pulse width counts the pulses. Then it is decided whether pulses can be obtained in the same cycle successively as many times as previously set each time the pulse number of the U or D counter is inputted.