In article ,
Timothy Murphy writes:
I'm looking for a gizmo to make a light go on when it is dark.
More specifically, it should go into a bayonet light socket,
and allow a bulb to plug in on the other side.

I've seen such devices (and in fact have one, by TimeGuard)
but they all seem to be far too clever,
and have various modes switching on and off at random,
but amazingly do not have a mode which simply switches on
when it is dark, and off when it is light.

You can buy compact fluorescent lamps with built-in photocell
which do this. There is a dependancy that the fitting doesn't
reflect too much light back into the photocell, or it obviously
won't work.

--
Andrew Gabriel