The closest would be to use light dependent resistor in conjunction with a transistor to make a "dark detector". I don't think there is a reverse photocell, they make energy from light not from dark.
Is there an off-the-shelf version of a photocell that works in reverse compared to the common variety?
I want something to come on when it is dark, and I don't want to use a relay in order to 'reverse' the position of the photocell.
It would seem that folks only associate photocells as lamp/light controlling devices and this is the sole way I have found them to be marketed.
If this item does not exist as stock, how much effort would it be to modify an existing model? If I need a few hundred of them, I wonder about getting them custom made. I can do circuits a little bit, but it requires quite a lot of studying beforehand.
Thank you.
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