I am looking to build a circuit to control the iris of a cctv lens. The input of that lens is a DC auto-iris type which is: pin 1: Damping- , pin2 Dampining+, pin3 Drive+, Pin4 Drive-. Here is a link on how dc auto-iris work http://www.gevicam.com/images/ED-_TN-07001AI_lens.pdf I can make a circuit to control the iris manually but it is not practical adjust it for all lighting conditions. Generally, CCTV uses the output of the video signal to adjust the iris opening size. How do I go about building such circuit for auto-light balancing?
This is part of my other project to use Arduino to control a manual zoom lens. I know how I can attach and control the zoom with servos but the iris part seems to cause me problems.