Brooke Clarke wrote:

> Hi Peter:
> 
> When I apply 5 ma to a lens the iris stays closed and by 10 ma it's wide open. 
>   This done with no connection to the damping terminals.
> 
> Is the control signal coming from the lens?
> 
> Any ideas on where to get the 4 pin plug and socket connectors?

Any good CCTV security company will have them in stock, or can order them for
you.  What style does your camera have (there is more than one '4 pin' interface).

Most cameras with the socket will have the needed drive electronics.
You just have to tell it which kind of autoiris is connected (DC vs AC).

As for open vs closed loop control, if your camera has AGC (I believe it does),
you can probably get away with bang-bang control. Wide open a night (when light
level drops. Use a CdS cell and comparator) and partially closed during the day.

Robert

I would suggest tipping your camera up so that is shows more sky and much less tree.
You did call it a 'sky camera' after all.

Other trick. Point camera down at hemispherical security mirror to get an 'all sky' view
from horizon to horizon, 360 degrees. This is commonly used for meteor tracking cameras.
(bolid recovery).




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