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Solar Arduino tracker (Quelltext anzeigen)
Version vom 2. März 2011, 12:56 Uhr
, 12:56, 2. Mär. 2011Created page with "To get Greenwich Time (aka UT) I use a DS1307 chip. Following the description of http://www.glacialwanderer.com/hobbyrobotics/?p=12 it worked immediately. Did not find any 2.2K r..."
To get Greenwich Time (aka UT) I use a DS1307 chip.
Following the description of http://www.glacialwanderer.com/hobbyrobotics/?p=12
it worked immediately. Did not find any 2.2K resistors, it worked with
4.7K as well.
I have taken the code from this site and tucked the complexity
into an Arduino libary (DS1307.h)
==Calculate Azimuth and Elevation==
To calculate the solar azimuth and elevation exactly
you need very involved formulas. However, for practical
purposes like sun tracking of a heliostat there are
simpler ones available.
Widely used formulas for solar tracking are the one from the so called
[http://dx.doi.org/10.1016/S0038-092X(00)00156-0 PSA-algorithm].
It has been made avaible from ''Plataforma Solar de Almeria'' (Spain)
and you can download it [http://www.psa.es/sdg/sunpos.htm here] as C++ code.
There are adaptions neccessary for Arduino, though.
The formulas for calculating the [http://en.wikipedia.org/wiki/Julian_day Juliand Day]
are not working properly on Arduino due to reduced double precision.
(doubles have the same precision as floats on Arduino)
Therefore, I have adapted them (expecting Julians dates from 1.Jan. 2000).
These calculations I have put into another library (Helios.h)
Following the description of http://www.glacialwanderer.com/hobbyrobotics/?p=12
it worked immediately. Did not find any 2.2K resistors, it worked with
4.7K as well.
I have taken the code from this site and tucked the complexity
into an Arduino libary (DS1307.h)
==Calculate Azimuth and Elevation==
To calculate the solar azimuth and elevation exactly
you need very involved formulas. However, for practical
purposes like sun tracking of a heliostat there are
simpler ones available.
Widely used formulas for solar tracking are the one from the so called
[http://dx.doi.org/10.1016/S0038-092X(00)00156-0 PSA-algorithm].
It has been made avaible from ''Plataforma Solar de Almeria'' (Spain)
and you can download it [http://www.psa.es/sdg/sunpos.htm here] as C++ code.
There are adaptions neccessary for Arduino, though.
The formulas for calculating the [http://en.wikipedia.org/wiki/Julian_day Juliand Day]
are not working properly on Arduino due to reduced double precision.
(doubles have the same precision as floats on Arduino)
Therefore, I have adapted them (expecting Julians dates from 1.Jan. 2000).
These calculations I have put into another library (Helios.h)