Autonomous, low-cost, automatic window covering system for daylighting applications

摘要

A system for the automatic regulation of daylight admitted into a room, specifically intended for daylighting applications. A preferred embodiment, system 10, consisting of a conventional control unit 11, a conventional exterior brightness sensor 12, and a conventional electronically controlled window covering 13, operates to block direct solar radiation while admitting substantial diffuse illumination. Control unit 11, brightness sensor 12, and window covering 13 are interconnected in a known manner to enable control unit 11 to register the brightness of the external illumination, and to actuate window covering 13. Control unit 11 consists of a conventional microcontroller 14, a conventional real-time clock/calendar 15, and a conventional Non-Volatile Memory (NVM) 16. Microcontroller 14, clock/calendar 15, and NVM 16 are interconnected in a known manner to enable microcontroller 14 to register the output of clock/calendar 15, and to exchange data with NVM 16. NVM 16 holds pre- stored data which defines a desired setting of window covering 13 as a function of the time of the day and the day of the year, for the prevailing latitude, longitude, and window azimuth orientation. In the preferred embodiment, this desired setting is one which will block the admission of incident direct solar radiation, while still admitting substantial diffuse illumination. Microcontroller 14 periodically registers the exterior brightness as measured by sensor 12, registers the data stored in NVM 16, estimates a desired setting of window covering 14 on the basis of these data, and actuates window covering 13 to the desired setting.