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Automatic chicken coop door opener

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DrJack

Jul 30, 2011
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Hello everyone,

I have a chicken coop with a sliding vertical door. Every morning I need to get up at 6am to open the door, and every night I need to close the door to protect my chickens. I have looked at commercial coop door openers, but they all retail at around £100 ($200). They look like fairly simple devices, and I would like to try and make my own (with some help from an electronics expert or two!)

Here is an example of an automatic coop door so you can get an idea of how the thing should function:

I have a rudimentary knowledge of electronics and mechanics, but this is beyond my capabilities. Here are some ideas that I had:

1) There is no mains electricity near my coop, so the device will need to run off batteries.
2) I have a low RPM battery-powered disco ball motor. This could be used to turn a spool of fishing line, thereby opening and closing the door.
3) A 12v timer could switch a relay at the appropriate time, sending the door up/down.

However, I can't get my head around how would I switch the motor polarity so that the door will both open and close, short of having two timers and two relays.

Any help would be greatly appreciated! If you need to know any more information then please do ask!

Jack
 

jbol

Jul 30, 2011
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a more mechanical solution would be to attach the edge of the door to a belt or chain around 2 pulleys - one a the top of the opening and one at the bottom. Half the time it goes up, then it goes down. Getting it to stop at the correct time is another issue.
I know there are switches and contacts out there to swap polarity but have no experience. It is educational to look how things like cd trays go in and out on a PC.
 

duke37

Jan 9, 2011
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Is this a repeat of a previous post?
I suggested then to use a car window mechanism which will run off 12V and have limit switches to define up and down.
 

DrJack

Jul 30, 2011
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I did a search but did not really like any of the solutions that had been proposed. To me the simplest way seems to be using a low RPM motor (which I have) with limit switches (which I have) at either end and a 12v timer (which I can get for £2.60) controlling it. I can grasp the mechanics of how it will work, but I don't have the expertise to design the circuitry.
 

duke37

Jan 9, 2011
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I have tried to engage a brain cell. Here is how I think it could be done if you have a permanent magnet brush motor which will reverse with reversed polarity. You will need two timers, one to raise and one to fall. You may be able to get away without the relay if your timers have more contacts.
 

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TBennettcc

Dec 4, 2010
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What about an H-bridge?

http://en.wikipedia.org/wiki/H_bridge

Might be able to use 555 timers...

I found this, don't know how easy it would be to copy. The last image on the page is the guts of the device. Looks like it uses magnets and reed switches, combined with knots in the line, as limit switches. Might be worth a look-see, in any case.

http://www.flytesofancy.co.uk/chickenhouses/Auto_Chicken_House_Door_Opener.html

I don't have enough brain activity right now to comprehend Duke's drawing... maybe I'll get it after a good night's rest.
 

poor mystic

Apr 8, 2011
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Hi Dr Jack :)
I think you're on the wrong track with the 555's.
Chickens like regularity. Chickens feel reassured when the door opens at the same time every morning. I don't think the 555's will impress the chickens
 

DrJack

Jul 30, 2011
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duke37 - Thank you for your help. I was thinking that I could get a couple of DIY relay light sensor circuits (http://www.rapidonline.com/Educatio...w/70-4150?source=googleps&utm_source=googleps) and could attach the relay outputs to the motor such that:

1) When light levels rise the first relay is activated which turns the motor turns in one direction, opening the door and stopping when a limit switch is activated.
2) When light levels fall the second relay is activated which turns the motor turns in the other direction, closing the door and stopping when a limit switch is activated.

TBennettcc - Thank you for your research. The image you showed me of the commercial product gave me an idea - why not have the limit switches activated by a knot in the string butting up against them as the door travels up and down?

What do you think?
 

DrJack

Jul 30, 2011
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...or I could just have one of these light-sensitive relay circuits with leads from NO and NC to turn the motor in opposite directions, couldn't I?

Jack
 

duke37

Jan 9, 2011
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The light switch looks like a good idea. How do you ensure that the chooks are inside before the door is closed? Could you put a microswitch under their perch?
Does your motor reverse when the supply is reversed?
 

DrJack

Jul 30, 2011
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duke37 - The chickens instinctively head inside when it gets dark. I need to find what the light levels are when they do this and set the relay to switch at this point. A microswitch under the perch is a great idea though, I might incorporate that. Yes, the motor reverses when the polarity is reversed.

Seems like i've got it cracked! Can you spot any glaring errors in my plan?

The board I have chosen has a delay function that stops the relay from being activated/inactivated by small changes in light levels. This is achieved by using a 100uf capacitor. If I was to increase the value of the capacitor would it make the light sensor less sensitive? I think it would be important to do this as I don't want the door going up and down with each cloud that passes over.

Thanks,

Jack
 

duke37

Jan 9, 2011
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Your light detector may have a dead band (Schmitt trigger) which can be adjusted to stop false triggering. The time constant of a resistor-capacitor combination cannot go above several seconds due to leakage in the capacitor, you could try 1000uF or even 10000uF.Checking that the chooks are in place would solve the cloud problem. The sensitivity is different from the time constant.
 

jackorocko

Apr 4, 2010
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So how would I achieve a longer triggering time (in layman's terms!).

use a binary counter. I like the idea of a trigger when all the hens have sit on their roost. This way you could use digital logic to close the doors based upon their instinctive behavior.
 

duke37

Jan 9, 2011
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Yes, a counter/timer could be used to check whether the light level was low for more than a specific time. This would take you (but not me) into the world of microcomputers.
 

Geekyheniac

May 20, 2019
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I don't have automatic coop doors on any of our coops (10) because of the cost and also reliability issues. Our coop doors are heavy to prevent predators lifting them and so don't need locking. Side sliding doors are not secure and external lifting doors are not much better. There are stragglers at night and you need to make sure they are not locked out, but if one has been taken you can't leave the door open all night so counting would be difficult. In our case many go in and out several times before settling. Our doors vary on the size of chickens but the largest is 400 high x 300 wide.
 
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