| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize a low power consumption without increasing the cost. SOLUTION: The signal from a detecting part 11 is inputted to a comparing part 14 through an amplifier part 12, and the comparing part 14 compares the input signal with the threshold of a threshold setting part 13 and outputs the comparison result to a judgment part 15. The judgment part 15 judges the entering of a person when three or more inputs exceeding the threshold continues, and an output part 16 outputs one pulse signal at this point of time. The pulse signals are continuously outputted from the comparing part 14 while the person is present. When the absence of input pulse continues three times in the judgment part 15, thereafter, the judgment part 15 judges the leaving of the person, and the output part 16 outputs two pulse signals at this point of time.</p> |
