I've been working on this issue (solar-powered, light activated raccoon-proof coop door) for a year. The car window motor works. In my case it drives a single pane window. Be sure to get the whole window regulator. A cable drive window regulator creates a nice linear action that requires a single bolt to connect to the window/door. The first version used a gear type motor that required too much precision.
Power is from a 12v lead/acid battery charged by a solar cell. Switching is from a photo resistor-transistor circuit switching a DPDT relay (so I can get up AND down).
Any advice on a simple 12v solar switching circuit? (please provide part numbers, my mechanical expertise outweighs my electronics expertise) that would last more than a couple months without frying? The parts from Radio Shack seem to be undersized for this application.

 

I too have been working on a chicken coop door solution (see the attached picture). I'm using a 3.6 volt cordless screwdriver motor from Harbor Freight. The spool winds up some cord which lifts and lowers the door. The chunk of aluminum angle is for a latch that will prevent the door from being lifted, but I've decided to remove it. The outside manual door is just held down by gravity and we've never had a critter get into the coop in the last 10-12 years. The old door is a chunk of 1/2" plywood; the new door is 1/4" birch plywood.

I quit working on this particular solution even though it works OK to raise and lower the door because I'd have to build a power supply for it and I don't have an appropriate transformer. Another objection to this DC design is that the limit switches I'll put on the door aren't rated for the 3-3.5A needed and I'm worried about reliability. If a switch failed, it could mean many or all of our chickens die (for a variety of reasons, although the main one is predators (foxes and raccoons)).

I'm looking for a nice Bodine gearmotor on ebay to do this job instead. I'm looking for a reversible AC or a DC one, both at 115 volts. My preference would be an AC motor, as the electrical stuff then becomes dirt simple. The DC is still pretty easy, as it's mainly some rectifying diodes and some resistors to drop the peak voltage to needed levels.

I plan to use a simple synchronous motor timer to open and close the door along with a DPDT relay. Our chickens don't have to be let out at any specific time (sometimes it's 10 or 11 am before they get let out), but I do want the door shut about 45 minutes after sundown.

I want things simple and reliable and it has to operate reliably for years in -20 °F to 105 °F weather. In winter, I might have to put a little box around the motor with a small light bulb to keep it warm, but that's no big deal.

I also decided to not use light-activated motors; that was my first inclination. The reason is that more components means less reliability and where I live, during the winter when we have snow on the ground and it's overcast, it can be quite bright at night due to the city lights getting reflected back from the clouds. I can easily see down the street. That makes the design a little harder -- the inclination is to use a timer signal to AND with the opening and closing signals. That's when it hit me to just use a cheap AC timer to begin with.

By the way, there's a company in the UK that sells a solution for 150 pounds. They're easy to find on the web and that might be preferable to spending a lot of time fiddling around. Of course, no self-respecting geek like me would buy something when they could have many hours of fun designing and building something...

 

I designed this circuit to tell me when the mail has arrived. It uses a cdS cell so that when night time comes it will turn this LED blinking circuit off and when morning comes it will turn it back on. You can adjust the sensitivity of the circuit to get the proper time but you don't have the same light every day. It might still work though. You could take this circuit and hook it up to a microcontroller like the BASIC stamp from Parallax. You can program it to turn a servo motor a certain way for a specified amount and then pause for a couple minutes and then you can tell it to turn the motor the opposite way thus closing the gate. I can give you the schematic of that circuit I built; it was origionally used to turn an LED on and off based on the time of day.

 

Hi everyone

I've just joined this forum in my quest to make life a lot easier for my chickens and me!

I have some chickens which I lock up safely in their coop at night. I put them in there and close a hinged trapdoor. However, so that they are nice and happy, I need to get up at dawn every day in order to let them out. I've been thinking about the possibility of a light activated switch system which would briefly power an electro-mechanical switch/servo. So..... the sun rises, a light sensitive device detects the light and powers something which will move a small arm (ie an arm which keeps their trapdoor closed), the trapdoor drops by gravity and the chickens run out into their chicken run. Maybe battery powered, say from a car battery??

Could anyone suggest how I can accomplish the above? (if at all). I can solder, make things and am generally handy with electrical things but I don't really know what's available or what to use. Can anyone help??

I thought it was the ROOSTER's job to get the chickens up at dawn!

 

uHH, The rooster has other duties, which he takes quite seriously. Something to do with making more chickens I believe.

Like I said in the beginning, the mechanics is the hard part, once that is done the rest is gravy.

 

Just some thought, but I'm no electronics expert. I'm not sure what your door looks like, but if it looks like the photo someonesdad posted. Couldn't you attach a low voltage linear actuator to the door and use a circuit (on a larger scale, I bet these guys could help with) similar to a solar light, just in the reverse sense. When sun comes up the actuator opens the door. It may work like a electric door lock on a car, pushing the actuator up would open the door. Just thought I'd try to help.