Active infrared sensors * ; * [, distance sensors; ] electric sensors; electronic sensors; electro-optical sensors; filters for optical devices; fire sensors; flame sensors; gas sensors; heat sensors; infrared filters; infrared sensors; [ light sensors; ] motion sensing input devices; [ oil change monitors; ] optical filters; optical sensors; passive infrared sensors; [ photoelectric sensors; piezoelectric sensors; pollutant sensors; proximity sensors; ] pyroelectric infrared sensors; smoke s...