| 摘要 |
A supervisory assembly incorporates a sensing means operatively associated with a TV set, so that one of the options available to the user is that when the sensing means detects someone it responds by altering the TV output. For example it may blank the screen, cut the TV power supply, or use the TV to make an alarm noise. …<??>The sensing means has a detecting device (1), the output of which passes through a signal processing circuit (2) so as to operate a switch element (4). The switch element can operate a TV control means (6), to affect the TV output. Other, conventional, alarms (5,7) may also be operated by the switch element (4). …<??>The assembly has use as a burglar alarm, and also for warning that someone is closer to the TV than a safe watching distance. In the latter case it is useful if the assembly's response is delayed slightly, so as to prevent it from giving the alarm when e.g. someone changes TV channel. …<??>The sensing means may operate by emitting a signal (eg. ultrasonic) and detecting any reflection of it. |
