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1  Forum 2005-2010 (read only) / Interfacing / Re: Arduino solar tracker on: July 12, 2010, 01:13:29 pm
I too have been thinking of how to track the sun to gather that extra 30% of energy, but the cost of most commercial solutions has exceeded the cost of installing 30% more solar modules...
I'm very new to the world of Arduino, and from the few forum threads on the subject, the popular method seems to track light levels to determine the position of "Ol' Sol" visually.
The downside I see with this methodology is that it is difficult to allow for all the variations and possible scenarios that the solar array may face, and have to algorithmically respond to.  
For example, will the tracker (in the examples given) properly handle  if a thunderstorm blows in mid-day ?  In other words, all of a sudden there is no bright spot in the sky; what will it do ?  I suppose it will stay put, because the two or three light sensors will "see" the same light level, am I right ?
Next, what happens at sundown ?  How does it know whan to go back towards the east and wait for sunrise ?  Without a sense of time (ie, with an RTC) I'm not convinced it will find the sun in the morning, mostly because the sun will literally be behind the light sensors.

With respect to razorbud's and tkbyd's comments about using lat/long information  to determine azimuth and elevation of the sun in real time, I think this is a great idea.  It solves a lot of problems in terms of where the sun is, regardless of time or weather.  It's not the simplest (no KISS here) but

The big question is: has anyone done this, to calculate the sun's azimuth ?    

I've read and looked at ve9qrp's qrptracker project, and how he uses keplerian elements and Plan13 formulas.  I'm hoping someone has some information to share on how to do this, to save from re-inventing any wheels.

Thanks to all in advance for any assistance...
2  Forum 2005-2010 (read only) / Exhibition / Adding voice - preferred shield ? on: June 16, 2010, 02:47:49 pm
I have a project in mind that requires outputting pre-recorded voice messages.  Specifically, I will have a timer and 4 or 5 push buttons, each assigned to play a voice message.  Pressing button #1 will play the first message, and so on.  Durations are short (<10 sec each), and messages will be transmitted over two-way radio, so recording quality and sample rates will be low.  Messages will be static, and seldom have to be changed.
Sketch-wise, there are excellent samples around that will make the programming task easy enough, but my question to the group is this:
Which shield would you recommend, the Spikenzilabs VoiceShield or the Adafruit Wave Shield ?

In particular, I'd like to hear about problems and successes with these shields.

Thanks in advance.
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