Hi All, I'm looking for ideas on how to improve my chicken coop door. Its a pretty basic affair - I'm using a DC motor with a DPDT relay for switching the polarity and magnetic reed switches as the stops in conjunction with reversing diodes and it works almost all of the time. Here's a short video that I made of it in action:

I've never had a failure in raising the door, but every once in a while it will fail to stop while lowering the door causing the motor to run until its completely wound out the spool and then it starts to wind up the backside raising the door until it binds the motor. I've revised the design a few times since the video to make the operation of the door smoother- partially enclosing it and improving the rails - and that has seemed to limit failures due to the door sticking, but last night I encountered a new problem. The fowl had fouled up the works - specifically there was a giant chicken poop preventing the door from closing completely. Does anyone have any ideas how I can wire up some sort of failsafe? In this case I'm thinking of cutting the bottom of the door to prevent this specific problem, but I'm sure that my contraption will be hobbled again by something I haven't anticipated and the problem is once the door winds up the back side there isn't anything I can do remotely since the reed switches are wired backwards in that case.

I was thinking that maybe another 'bottom' reed switch wired in parallel in a second position might work, but I'm not sure. Looking for ideas from some people smarter than me.

Thanks for reading!

 

Frank Perdue would be proud and, at the least, I am impressed by your skills.

Let me ask you this - how do you want the door to behave in the case of an obstruction (poop or otherwise)? Do you want it to sit as far as it can go, or come back up or sound an alarm or?

 

Thanks for the compliment!

Good question - Sitting as far as it would go would work, just so long as it doesn't start winding the other way I can control it with my telephone so that way if I'm out and about I could at least raise it back up and try lowering again to attempt to power through any obstruction. I've got a wireless ip camera set up so I can count the chickens and check the door.

This part is where my brain starts freezing up though because if I have the failsafe located in a middle type position it would prevent it from ever closing properly. I was also thinking of adding a timer to the motor so that it can only run for a specified time, but I don't know of any timers that work in second increments. I guess I could make the string really long to increase the time.

Anyway, I appreciate new eyes on this because its broken my brain

 

I would use a timer set for a few seconds longer than it normally takes the door to close.
Modules that can be set in one second increments are readily available, such as one of these.

 

Thanks for the compliment!

Good question - Sitting as far as it would go would work, just so long as it doesn't start winding the other way I can control it with my telephone so that way if I'm out and about I could at least raise it back up and try lowering again to attempt to power through any obstruction. I've got a wireless ip camera set up so I can count the chickens and check the door.

This part is where my brain starts freezing up though because if I have the failsafe located in a middle type position it would prevent it from ever closing properly. I was also thinking of adding a timer to the motor so that it can only run for a specified time, but I don't know of any timers that work in second increments. I guess I could make the string really long to increase the time.

Anyway, I appreciate new eyes on this because its broken my brain

I am confident that there will be some suggestions.

I am just thinking out loud, but a pressure-resistive strip along the bottom of the door might come in handy. The idea being that you can tell when the door has hit an obstruction or the floor. If the door has hit the floor, then both the limit switch and the resistive "switch" will be triggered. If the resistive switch but not the limit switch has triggered, then it is obstructed.

You can probably get some kind of mechanical switch instead of resistive film, but the idea is to have a switch on the bottom of the door itself.

I wonder if that might be an approach, but keep in mind that I am far better at eating chickens than provide them room and board.

 

When the door opens.....instead of seeing open square access........we should see a round hole. This should be a thin metal plate with a hole in the middle. Thin so they don't sit there. And hopefully with the thru hole velocity......poop accumulation should be at a minimum. A thin plate for gate should cut some poop too. A one inch or so plate at bottom of gate would help.

You should seal the door and rails against moisture. disassemble door and rails.....several coats of sealant....And then wax.

And of course an alarm when not properly closed........And an alarm when everything is suppose to be closed....i.e.theft.

 

Thanks! These are great ideas. Half of the battle is knowing what things are called or even if they exist! I think I'll wire up a mini timer right away. That should eliminate the possibility of back winding.

I really like the idea of the pressure-resistive strip. I had no idea there was such a thing. I considered wiring in a IR break-beam sensor to make sure that there weren't any hens in the way when it closes but the strip might be more useful and fowl proof. For instance, I could see a hen craning her neck out to look around without interrupting the beam. Right now the only safety feature of my door is that it is very lightweight and couldn't crush a chicken. Its only a matter of time when one gets stuck that way, they have a natural instinct to crouch down if something is on their back. I'm guessing with the pressure resistive strip I'd probably have to go with a microprocessor/arduino, but I reckon I could figure it out.

The round hole is a good idea- hostile architecture certainly has its uses in constructing a chicken coop and run. You'd have to be careful though - depending on your particular hens predilections you could have just created a perching spot since they have to fly through. I had one years ago that loved to perch on things as thin as electric fence wire, and if it was at all sharp you could end up with a case of bumblefoot. Unfortunately, in my case the layout is probably going to prevent modifying that opening - I've got different heights to accommodate for which requires ramps and its going through an exterior wall in my barn- through both siding and cladding so its pretty thick. Good idea to incorporate into a new coop design though.

Thanks again for the help - ya'll have really helped point me in the right direction!