On average, households have about 12 windows, normally located in spread out locations over the perimeter of the house; people generally have them blocked at night and opened in the daytime. Currently, the most common mechanism for regulating light flow is through miniblinds, which use a separate mechanism for allowing a certain amount of light in (twist wand) and for removing the blinds from obscuring the window completely (drawstring). Sometimes, access to these means of adjustment is difficult due to placement of furniture.
An alternate proposal employs automated polarized films to do exactly the same thing. Rather than manually adjusting all window blinds in the morning, at night, and then periodically throughout the day, this automated system would automatically adjust according to brightness. The user first adjusts the window until the room is at the brightness desired. Then, an automatic setting will adjust the rotation of a polarized film until the brightness in the room matches the initial setting. Of course, the use of polarized lenses will limit the amount of light to enter the room to only about 40%, so there is an option to remove the polarized film to improve visibility to the outside.
Benefits of the SmartWindow
There are multiple advantages to the use of polarized film windows.
Time efficiency: The most apparent advantage of most automated systems is the time saved by not needing to adjust the curtains or miniblinds throughout the day.
Energy efficiency: During the summer months, households regularly let in a lot of thermal radiation through windows, thus increasing the costs of air conditioning. Similarly, in the wintertime a lot of heat is radiated through the windows as well, leading to increased use of the heater. The use of automated polarized windows offers a simple solution to this. It detects the presence of people through an infrared sensor, and then simply closes windows when no one is around. Thus, for a typical 2,200 square foot house, about $40 in energy costs can be saved by restricting radiation when the room is not in use.
Reliability: The design is simple and relies on only a few gears and motors, and a manual non-electronic adjustment switch could be installed as well, if electronic components fail.
Safety: A study shows that a common household danger to babies is the drawstring on miniblinds, which is something that will be removed completely with the introduction of the polarized system.
Pictures of the Prototype
Click on any of the following image links and scroll through with the arrow keys.
SmartWindow is a rotating polarized window that allows in an optimal amount of light based on light detection and user input. Constructed with polycarbonate window panes and coded in Arduino, SmartWindow aims to serve as a foundation for an energy-saving, sustainable window concept. The project was conceived within the ME102 senior design course at the University of California, Berkeley during Fall of 2009.
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