automatic door latch design ?

[knighthawk]

how can I design a door latch that will operate with a timer ? I have a chicken door, about 12 x 15, that drops down to open like a gangplank. If I could get a timer to unlock the ramp, it could fall down to open.............thanks

 

[j3707]

I think a timer and power door lock actuator could work well in your situation. Check out how this guy uses them to close his coop door:


http://www.nifty-stuff.com/auto-coop-door-prototype.php