- 天同Lv 79 years agoFavorite Answer
The crucial point is the intensity of the infared.
Although there exists an infared background from other objects and from the environment, their intensity is rather low. The infared sensor on the appliance has been tuned not to respond to such low intensity infared radiation.
When you shoot a beam of infared from your remote control to the appliance, the sensor detects an infared level that is much higher than background and is sufficient to trigger the sensor operation, thus switching on the applicance.
- 9 years ago
因為每個遙控器都用着不同的frequency, 除非你D interference 係果個特定frequency撞到應一應, 但其實都冇咩可能, 因為從數學上看來, frequency spectrum係continuous的, 即係有無限個frequency, 好難這世上有一個controller with arbitrary frequency會撞重你果個。
熱力都係... 好難會熱到arm arm好果個温度...