| 摘要 |
<p>A power supply control unit 1 for automatically turning off a multimedia projector or an interactive whiteboard. The unit comprises a battery powered timer 2, a relay, an external light sensor 7 and a remote control unit. The light sensor is located in front of the projector lens and when it is triggered by light emitted by the projector it sends power, via the relay, to the remote control unit. At a given time programmed into the timer, a signal is sent to the remote control unit to turn the projector off safely, allowing the projector's built in fan to gradually cool the bulb. The unit is particularly suitable for use in schools where the programmed times may be break time, dinner time and home time. The projector is turned back on manually.</p> |
