It's going to need to reverse the voltage to close the door, is that possible with a motor control board?
With the timing, would it be better to use a clock with an offset to work out sunset\sunrise or rely on the LDR? (Or maybe both?) I guess it could be programmed to check the amount of light of a set period to stop false closure from shadows\clouds etc?
I'm not sure if I should use an RTC with a calculation or an LDR?........Sunrise @23 june = 4:41 = 60 * 4 + 41 = 281........
Thanks for your reply. The mechanics are actually the biggest headache for me - I don't want to damage the coop.What type of motor should I use? (I'm a programmer, the hardware is a mystery to me!)