The sun is incredibly important to the contextual smart home. Accurate information about the sun plays a key role in delivering a great user experience. Information about the sun can be used to automate blinds, curtains, lighting, etc. and this is a big part of a luxurious and hassle free user experience. Knowledge about the sun is also key to our current smart home's smart energy management.
The sunrise time can be calculated mathematically but it is also easy to obtain this data for your location from an Internet source. We actually do both for a higher level of confidence and to also remove cloud dependencies.
The sunset can be calculated mathematically too but, it is also easy to obtain this data for your location from an Internet source.
Twilight on Earth is the illumination of the lower atmosphere when the Sun is not directly visible because it is below the horizon. Twilight is produced by sunlight scattering in the upper atmosphere, illuminating the lower atmosphere so that Earth's surface is neither completely lit nor completely dark.
Twilight is detected by using a 'twilight sensor' (a light level sensor) to determine local 'dawn' (start of day time) and 'dusk' (start of night time) times. This is a really valuable source of information and context for the contextual smart home. These times are key drivers for a lot of smart home automation and can be used as inputs into a controller, to enable adaptive schedules.
Knowing when dawn (the start of day time) occurs is valuable information to the contextual smart home. This is because it takes account of local weather conditions and on cloudy days it can get darker later earlier than the sunrise time would have you believe. This means that can be automated more intelligently and lighting will stay on longer, whilst it is still dark, delivering a much better user experience.
Occasionally our @smartest_home tweets in real time at dawn.
Knowing when dusk (the start of night time) occurs is also valuable information to the contextual smart home. On a really stormy day it can get darker much earlier than the sunset time would predict. We have seen differences of nearly 3 hours between detected dusk and the predicted sunset time.
Occasionally our @smartest_home tweets in real time at dusk.
Azimuth is the angle along the horizon, with zero degrees corresponding to North, and increasing in a clockwise fashion. Thus, 90° is East, 180° is South, and 270° is West. We use a software algorithm to predict both the azimuth and zenith for our location, so our @smartest_home always knows where the sun is in the sky.
Occasionally our @smartest_home tweets in real time about the solar azimuth.
The solar zenith angle is the angle between the zenith (a point vertically above the observer) and the centre of the Sun. The solar elevation angle is the altitude of the Sun, the angle between the horizon and the centre of the Sun. These two angles together add up to 90°. The solar zenith is an input to our smart energy management.
Occasionally our @smartest_home tweets in real time about the solar zenith.
We also have two sensors connected to our smart home, which measure the outside UV level and the intensity of the sunshine. The latter can basically inform our smart home that the sun is out and provide a measure of its intensity.
Our smart home also has solar power, so it knows about the solar power being generated, the total solar energy generated each day and it also predicts solar energy.
My @smartest_home sometime tweets about the Solar Power.
It is also quite useful for the contextual smart home to know about seasons. These can be used by our dynamic controllers to enable more powerful control.
