Support for Getting Angle of Sun (Altitude/Azimuth)

[giesen]

Is there any possibility for getting variables that indicate the altitude and azimuth of the Sun? Maybe include it in the climate module? I'd like to be able to open/close blinds based on which windows the Sun is facing, and various other neat things. I realize this might be possible with light sensors, etc, but this solution doesn't require any hardware and I would think should be relatively easy to implement.

[Teken]

Is there any possibility for getting variables that indicate the altitude and azimuth of the Sun? Maybe include it in the climate module? I'd like to be able to open/close blinds based on which windows the Sun is facing, and various other neat things. I realize this might be possible with light sensors, etc, but this solution doesn't require any hardware and I would think should be relatively easy to implement.

 

Could you expand on how this would operate in practice assuming this feature could be added? I am coming up a little short in envisioning how you could make very specific distinctions with in a home that provides no feed back?

 

1. What tells the system room A is XYZ?

2. Can knowing Altitude really know a window is on the second floor opposed to being on the main floor?

3. If you have two windows at 90' angles how does Azimuth compensate for that?

[giesen]

Could you expand on how this would operate in practice assuming this feature could be added? I am coming up a little short in envisioning how you could make very specific distinctions with in a home that provides no feed back?

 

1. What tells the system room A is XYZ?

2. Can knowing Altitude really know a window is on the second floor opposed to being on the main floor?

3. If you have two windows at 90' angles how does Azimuth compensate for that?

 

1) The presumption was it would be up to the user to determine what actions to be taken depending on what range the azimuth/altitude fell in (ie they'd have to know where their windows are and work it out). But at least they wouldn't have to account for the changing position of the sun over the course of the year.

 

2) While Azimuth is definitely the more important variable, Altitude is useful not for targeting first-storey vs second-story windows, but more for if the sun is directly overhead and not hitting any windows (ie nearly 90 degrees)

 

3) Again up to the user. This request is not about doing all the work for the user, it's about allowing them to do it at all...

 

I'd envision something like this in terms a program

 

IF

Azimuth  >= 0

AND

Azimuth < 90

AND

Altitude >= 0

AND Altitude < 75

THEN

Close Front Windows

 

IF

Azimuth  >= 90

AND

Azimuth < 180

AND

Altitude >= 0

AND Altitude < 75

THEN

Close Side Windows

 

etc.

 

*Edited for clarity*

[Teken]

1) The presumption was it would be up to the user to determine what actions to be taken depending on what range the azimuth/altitude fell in (ie they'd have to know where their windows are and work it out). But at least they wouldn't have to account for the changing position of the sun over the course of the year.

 

2) While Azimuth is definitely the more important variable, Altitude is useful not for targeting first-storey vs second-story windows, but more for if the sun is directly overhead and not hitting any windows (ie nearly 90 degrees)

 

3) Again up to the user. This request is not about doing all the work for the user, it's about allowing them to do it at all...

 

I'd envision something like this in terms a program

 

IF

Azimuth  >= 0

AND

Azimuth < 90

AND

Altitude >= 0

AND Altitude < 75

THEN

Close Front Windows

 

IF

Azimuth  >= 90

AND

Azimuth < 180

AND

Altitude >= 0

AND Altitude < 75

THEN

Close Side Windows

 

etc.

 

*Edited for clarity*

 

I think what I missed was the obvious part which was clearly stated in your title.

 

Please correct me if I am wrong here: What you're saying is if the HAM Weather Module can track the ever changing Altitude / Azimuth during the course of winter, summer, fall, spring when that information is available your program will close the appropriate shades, correct?

 

Some how I envision a simple light sensor doing the same thing. But agree one costs money and the other just requires some invested time in programming.

 

I would think using any of the MS sensors with the Dusk to Dawn feature would also allow you to accomplish a similar goal, no?

[stusviews]

A goal is to close the window covering only when the sun is shining directly on the pane. A simple light sensor can't distinguish between light, very light, bright and very bright. Depending on the orientation of the structure, two to four sensors are needed. OTOH, azimuth and altitude can't adjust for cloudy or rainy days.

 

The most common, although costly, solution is a sun sensor designed especially for the purpose.

[giesen]

I think what I missed was the obvious part which was clearly stated in your title.

 

Please correct me if I am wrong here: What you're saying is if the HAM Weather Module can track the ever changing Altitude / Azimuth during the course of winter, summer, fall, spring when that information is available your program will close the appropriate shades, correct?

 

Some how I envision a simple light sensor doing the same thing. But agree one costs money and the other just requires some invested time in programming.

 

I would think using any of the MS sensors with the Dusk to Dawn feature would also allow you to accomplish a similar goal, no?

 

Yes and no. I'd looking to know not just if their is light (since there would be light all day), but the intensity. Again it could be achieved with light sensors (that measure intensity), but like I said, it could be approximated fairly closely just by calculating the position of the sun, doesn't require any hardware investment, and probably more importantly, does't require any wiring or having unsightly sensors in your windows/outside.

[giesen]

A goal is to close the window covering only when the sun is shining directly on the pane. A simple light sensor can't distinguish between light, very light, bright and very bright. Depending on the orientation of the structure, two to four sensors are needed. OTOH, azimuth and altitude can't adjust for cloudy or rainy days.

 

The most common, although costly, solution is a sun sensor designed especially for the purpose.

 

 

Yeah, obviously Azimuth and Altitude can't compenstate for cloudy/rainy days, but combine it with the data from the Climate Module (which does provide that info) and you can. Even if it's not 100% accurate, the cost of getting the sensors (and installing them) means your payback (in terms of energy savings) is a lot longer.

[giesen]

Just to be clear, the data is not currently available for HAMWeather, but there are formulas to calculate it. My suggestion of including it with the climate module was that a) it seemed to fit best there, and UDI might sell a few extra climate modules if the data were available.

 

Think not also just about energy savings, but things like if you're sitting in your office and the sun is shining right in your window on your monitor. Having access to that data makes it inexpensive and easy to solve those kind of problem s.

[io_guy]

Don't know if you use any of my Link programs but if you point me to the calcs I'll add the variables to ISYLink

[MWareman]

This is an awesome idea! I know celestial locations and paths are published periodically (I used to operate, years ago, a multi yagi antenna on a two axis rotor that we used to track NOAA Satellite passes every few minutes to get the longest possible passes). I'll see if I can dig up the code, because I know it could spit out the current altitude and azimuth of the sun. Cannot promise though! (It was a *long* time ago!)

[MWareman]

Here is the Navy's system: http://aa.usno.navy.mil/data/docs/AltAz.php

[MWareman]

..and the formulas for calculation are here: http://www.pveducation.org/pvcdrom/properties-of-sunlight/suns-position

[io_guy]

..and the formulas for calculation are here: http://www.pveducation.org/pvcdrom/properties-of-sunlight/suns-position

 

Just found this myself (same site).  I used their advanced formula page and have it up and running.  Will add this to the next release.

[MWareman]

Awesome! Thank you. This is one of those things that you don't know you want until you find out about it. ☺

[builderb]

Oh yes, I like this. Great potential for shading, particularly when combined with the season variable. Thanks!

 

 

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[Michel Kohanim]

Hi giesen,

 

Thank you for the feedback. We already get station's elevation from HAM and can easily add it to programs. This said, I do not see any value since this is a static value: your altitude and elevation do not change.

 

As far as Azimuth, we do use solar declination to calculate the irrigation requirements alas this is done on a day to day basis (and not minute by minute). I doubt this would be sufficient for what you are looking for.

 

With kind regards,
Michel

[giesen]

Hi giesen,

 

Thank you for the feedback. We already get station's elevation from HAM and can easily add it to programs. This said, I do not see any value since this is a static value: your altitude and elevation do not change.

 

As far as Azimuth, we do use solar declination to calculate the irrigation requirements alas this is done on a day to day basis (and not minute by minute). I doubt this would be sufficient for what you are looking for.

 

With kind regards,

Michel

 

Michel,

 

Altitude was not in reference to height above sea level, it's a reference to the angle of the sun from the horizon (0-90 degrees) (see https://en.wikipedia.org/wiki/Horizontal_coordinate_system).As for azimuth, while I don't think you necessarily need it minute by minute, 10 or 15 minute increments might be nice. But if you're calculating it anyways, it shouldn't really matter. That being said, I take it UDI is not interested in adding support for this? (just trying to understand what my options are - ie. ISYLink). Obviously I'd prefer to see this integrated right into the ISY but I'll have to take what I can get, I suppose.

[giesen]

Michel,

 

Since you already have the Sunrise/Sunset and declination, wouldn't it be possible to calculate the Altitude/Azimuth using the formulas on this page:

 

http://www.itacanet.org/the-sun-as-a-source-of-energy/part-3-calculating-solar-angles/

[Michel Kohanim]

Hi giesen,

 

We would be interested if there's a lot of demand. I can certainly add it to our requirements list but given the intrusive nature of the change (have to dissect the code for which sunrise/sunset/irrigation depend on) in addition to yours being the only request, it will have very low priority.

 

With kind regards,
Michel

[stusviews]

I'll add a vote for inclusion

[Teken]

I'll add a vote for inclusion

 

I believe the OP should create a POLL so it could be easily tracked for UDI. I also cast my vote for inclusion as it may provide an alternative to a hardware solution.

 

In the big picture using some kind of hardware will get you up and running much faster than waiting for this feature to be developed and released. As noted by the OP that directly translates to more costs, and hardware that must be affixed into places that may not be easy to install to.

[giesen]

I believe the OP should create a POLL so it could be easily tracked for UDI. I also cast my vote for inclusion as it may provide an alternative to a hardware solution.

 

Poll added, cast your votes!

[Guitartexan]

!

 

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[giesen]

FYI io_guy has now implemented this in ISYLink (v0.5.7), and seems to be accurate (compared it to a couple online sources) and work quite well. While I'd still like to see this directly integrated into the ISY, this is definitely a workable solution. My hat off to io_guy for implementing this.

Thanks!