人じん感かんセンサー

noun

human sensor; motion detector

A device that detects human presence or movement, commonly used in lighting, security, and automatic doors.

• 廊ろう下かの人じん感かんセンサーが反はん応のうして、自じ動どう的てきに電でん気きがついた。

  The motion sensor in the hallway reacted and the light turned on automatically.