Author Topic: SOLAR TRACKER, Totally Different, Totally Original, DIY  (Read 24065 times)

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David HK

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Re: SOLAR TRACKER, Totally Different, Totally Original, DIY
« Reply #33 on: May 22, 2011, 12:25:36 AM »
Windy, the distance between the CDS sensore is about 25 to 30mm.

They are housed in individual weatherproof containers with a wire link In between each sensor is a shadow maker made from black plastic measuring about 8 inches by 11 inches. The CDS sensors are housed inside copper pipe pots which have been covered by soldered on copper discs each with a 1.5 mm hole drilled in the top.

Some photographs are shown below:-





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David in HK

David HK

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Re: SOLAR TRACKER, Totally Different, Totally Original, DIY
« Reply #34 on: May 22, 2011, 12:27:53 AM »
Try again - two more phoptographs:-




David HK

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Re: SOLAR TRACKER, Totally Different, Totally Original, DIY
« Reply #35 on: May 22, 2011, 12:31:53 AM »
Might get it right this time with the ruller showing for clarity:-


David HK

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Re: SOLAR TRACKER, Totally Different, Totally Original, DIY
« Reply #36 on: May 22, 2011, 02:08:55 AM »
For clarity, I did not design the circuit mentioned in my earlier post.

I merely copied it and it has run flawlessly for many years.

David in HK

Madscientist267

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Re: SOLAR TRACKER, Totally Different, Totally Original, DIY
« Reply #37 on: May 22, 2011, 12:18:44 PM »
Humidity would not be a problem.

Once it is built, the entire thing would be potted in epoxy.

That circuit is a direct replacement for the night watchman that he is already using.

3 wires enter the potting - hot, ground, and output - everything else except the RTE switch is protected by the epoxy.

The variable resistor is the only component that would potentially have any exposure to the elements, but there are ways to protect that as well.

If using a trimmer with a tweaker adjustment screw, I use a skinny straw preassembled to the pot, held in place by RTV (or hot glue as long as the straw doesn't deform too much), then leave the straw snorkelling out of the potting, trimmed flush once the epoxy cures. After tweaking is done, a blob of RTV can cover the hole to seal it, but is easily removed/replaced later if another adjustment needs to be done.

If using a 'standard' shaft pot, a seal can be made by putting a thin coat of dielectric grease on the shaft, then running a quick bead of RTV around it, making an O ring. Seal all open gaps on the pot with RTV to prevent the epoxy from fouling it during potting. It's not the easiest process, but I've done it and it works.

For ease of construction, and better fine control, I recommend the tweaker pot instead.

Steve
The size of the project matters not.
How much magic smoke it contains does !