Photocell backwards / reversed

[Ryan]

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.

 

[Impmon]

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.

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.