Photo cell turns on landscape lights too soon

I recently installed a new transformer for my landscape lighting that has a built in photo cell. It is very similar to this one.

https://www.yardbright.com/product_detail.sstg?id=105&catid=56&menu_catid=34

The way it works is that the cell detects the darkness and either triggers on the lights until dawn or a predetermined number of hours after first triggered. I tried to get a schematic or some type of documentation but it does not eppear to be available.

The problem is that the cell trips too easily. The lights will come on if it is cloudy or when the sun moves from the front (where the transformer is) to the rear of the house. Does anyone have any ideas or experience with this type of circuit? Is there some way to increase the level of darkness before the lights turn on? What additional information should I try to get that would help you develop a solution?

BTW, I contacted the vendor and he told me that's the way they all work. He sugggested I add a timer to turn on the transformer at a later time in the evening. The original reason I bought this unit was to not have to worry about resetting a times whaen the power goes out.

Is the photo cell movable? If not, perhaps you could remove it, add a wire extension and mount it where it gets more light from the sky. You might also try adding a reflector around the cell to catch more light. You could fashion a rough parabolic reflector from aluminum foil, or use an old flashlight reflector. One from a large lantern should be particularly effective.

If it's a CdS cell you could connect a resistor in parallel with it, I don't know what value you should use, experiment with anything bewtween 470k and 10M.

Could be a bad design...or be a bad unit. Since it's new and not working "as sold", have you considered taking it back for a replacement?

Ken

holabr said:

The problem is that the cell trips too easily. The lights will come on if it is cloudy or when the sun moves from the front (where the transformer is) to the rear of the house. Does anyone have any ideas or experience with this type of circuit? Is there some way to increase the level of darkness before the lights turn on?

add a timer to turn on the transformer at a later time in the evening.

Click to expand...

I made one with adjustable sensitivity. The cell was mounted very inconspicuously in the brick wall a foot or two below the porch light that was controlled. I used a two transistor Schmitt Trigger.

It turned on too early in the evening.
When I adjusted it, the thing would oscillate if you walked in front of it with a jacket that was only slightly reflective. Of course, if you held a mirror up to this arrangement the whole thing would flash on and off at a few Hz.

Surprisingly, there was no optimum sensitivity adjustment.

IMHO, a timer, photocell and maybe even some logic circuitry is the best solution.