Rest In Peace Grey Chicken
I’ve been wanting to design an automatic chicken coop doorÂ closer for years.Â Â There are plenty of other systems out there that automatically open and close the coop door, but they are expensive and, well, not designed by me!Â 😉
Basically my idea is to create a simple system that is a “safety net” in case we don’t remember to lock our girls in at night.Â IÂ have no problems letting the girls out in the morning, but I want to ensure they are closed up safe in the evening.Â Â I learned my lesson the hard way one night when I got home late from a party and a coon had killed my favorite hen.Â
Some have commentedÂ “What if all the girls don’t get in the coop in time, or get caught in the guillotine door as it closes?”Â Â My response: I don’t think I’ve ever found my girlsÂ outside of the coop when it is dark.Â Â For my auto coop door I’d set the timer to go off an hour after dark to ensure they are all in.Â Remember, my design is more of a fail-safe than a system to 100%Â rely on, I don’t know if any auto system is.
I’m always worried that I’ll forget to lock up the girls, this auto close system at least give me some insurance just in case we forget.Â Â If it works really well then you only need to check in occasionally to verify the girls are always getting in and that the door is closing properly and at the right time.
In my opinion, I’d rather risk loosing one hen that didn’t get into the coop in time instead of loosing all my girls because I forgot to lock them up.
My first auto coop door design called for an electromagnet holding the door open.Â At night I’d cut the power and the door would fall. Â I found problemsÂ very quickly with this design,Â mostly heat, energy loss, etc.Â Â I then moved to a different electromagnet, a type ofÂ “pull solenoid” to pull a pin to release the door.Â Â There were problems with that design too, it required too much power to move a solenoid strong enough to pull a pin.
So far, the best thing I’ve played with is a car lock actuator I bought on ebay ($11 shipped for two).Â Â Â My basic design is simple, Â I’m thinking about using only three parts:
- AÂ $5 wall adapter
- AÂ $5 lamp timer
- A $5 car lock actuator
Below is a sketch of the design.Â Â Here is how it works:
At night the timer hits the pre-setÂ “on” time and sends power through the adapter and turns on the actuator
The actuator pulls a pin which releases the coop door
The door falls and covers up the coop access
The “door latch” (in red) is an “L” shaped piece of metal with a pin in the top which allows it to swing.Â Once the door passes the bottom of the latch it swings to the right (gravity wants to center the metal) and the latch locks the door into place.
In the morning I simply move the latch to the left, raise the door, and hook the pin.
MyÂ biggest problem with this design is this:
The shortest amount of time I can set on this type of timer is 30 minutes.Â This would mean the actuator would be trying to “run” for the whole 30 minutes and would probably burn out the tiny geared motor.Â The resolutions to this could be:
- A digitalÂ lamp timer that allows you to set muchÂ smaller increments of time.Â I think as low as 1 minute of “on”.
- Create a switch activated by the door, so either it powers the actuator when the door is up, or cuts powerÂ to the actuator when it falls.
I should also mention that my situation is a bit different than most because my girls have a small run they can access during the day.Â The coop door I’ll be opening is actually the door that goes from this small chicken run out to the open backyard.Â Opening the door to “the great outside” is the one I want to automatically close.
So, what do you think of this design?Â What would you add or change?Â Â I’d love some feedback, especially from the engineering / tinkering types that read this website!!!
Update 10/27/08: I Finally have a prototype!!!Â Automatic Chicken Coop Door Closer