Hi pebe, thanks for replying.
I'm trying to create an automatic door opener for a chicken coop, but am a complete novice to electronics so am learning as I go. There seems to be lots of information out there, but nothing definitive.
I've seen some ideas fo light sensor only circuits, but am worried that during the summer months the door would open too ealy in the day/late at night.
What I'm hoping to do is have a 12v DC motor activate based on a timer, or a light sensor (photo resistor based circuit) and turn in one direction until the door mechanism reaches a limit switch which stops the motor.
Then have the motor turn in the other direction when the light sensor/timer activates it, thus closing the door. Again a limit switch could stop power to the motor allowing for the use of different sized doors.
Perhaps a 3 way switch could select timed/automatic(light sensor)/manual operations with the later being push buttons to open/close the door on demand.
I was thinking it would be good to have maybe a red LED and green LED for Open and Closed status of the door. that way I could see at night if the door has been closed.
I'd like to encorporate a solar charging unit for the battery too, so I don't have to worry about them.
I think I might have found a simple solution to the timer here http://www.reuk.co.uk/Convert-Digital-M ... oltage.htm
so could use ths as the timed switch.
If you have any circuits that may be of extra help I'd really appreciate it. Any advice on the motor to be used is welcome too, I have some salavaged motors, including stepper motors.
Feel free to tell me if this is overkill/over engineering the entire thing or if I've missed something important.