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Following the sun ( no programming )?

Discussion in 'General Electronics Discussion' started by CyberWizard, Oct 27, 2014.

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  1. CyberWizard


    Sep 17, 2014
    I have an idea for a project running a stirling engine + fresnel lens or fresnell + radiator to heat water
    My questing is:
    Do i need programming to make my circuit follow the sun ?
  2. Arouse1973

    Arouse1973 Adam

    Dec 18, 2013
  3. Gryd3


    Jun 25, 2014
    Programming, or a purpose built circuit.
    Think ;)
    You simply point two at the sky, with some kind of divider between the two, and your circuit will cause the device to turn toward the brighter photoresistor until both are at equal brightness (pointed at the source)
    Have one device for horizontal rotation, and one for elevation ;)

    Edit: ... Adam just Ninja'd this post ...
  4. hevans1944

    hevans1944 Hop - AC8NS

    Jun 21, 2012
    Probably. I visited a solar-heated model home in Tuscon AZ, sometime around 1979 while interviewing for a job with Hughes. This was a demo model solar installation, part of new housing sub-division. The solar water-heater had maybe fifteen or twenty black-painted tubular collectors, mounted at an angle to the horizon appropriate for that latitude, and located at the focus of fairly large cylindrical pseudo-parabolic reflectors. The collectors were fixed plumbing, but the reflectors could rotate about the tubes to follow the sun.

    The reflectors had a linkage mechanism that caused all the reflectors to move together, and they were driven by a small DC motor, or maybe by a split-phase low-voltage AC motor such as used on antenna rotators. Anyway, they had a clever device to make the reflectors "follow the sun". It was just a small aluminum "I-beam" with two photo-sensitive cells mounted on the "lip" on either side of the beam. The long axis of the "I-beam" was attached to and oriented parallel to the axis of one of the cylindrical reflectors. When pointed directly at the sun, the sun cast two equal shadows on either side, from the top of the "I-beam" toward the photocells mounted on the opposite base, thus illuminating both photocells equally. As the sun moved across the sky, the amount of sunlight one cell received increased as the other cell deceased. This differential change in photocell output, when it reached a sufficient level, actuated a relay that energized the motor to move the reflectors in the proper direction to track the sun.

    I didn't stick around long enough to see it actually track the sun, nor did I ask how it was reset at sundown to be ready for sunrise the next day, but that would be a design consideration for unattended operation. The whole thing looked totally out of place for an up-scale residential neighborhood, and it consumed a good portion of the back yard. I don't remember how many rows of these collectors there were, perhaps only one, but probably more. I think they intended to use it to heat swimming pool water. There was steam escaping from over-pressure vent valves the day I visited.

    Anyway, even if you only have one Fresnel lens to heat the water for your Stirling engine, you will probably need to track the sun to obtain maximum efficiency from it. Minimal or no programming required
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