DIY Chicken coop door opener

Discussion in 'The Projects Forum' started by DrJack, Jul 30, 2011.

  1. DrJack

    Thread Starter New Member

    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:
    http://www.youtube.com/watch?v=cXLPdCbk8dA

    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
     
  2. someonesdad

    Senior Member

    Jul 7, 2009
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    Chicken coop door automation has been discussed many times on this board, so I suggest you use the search function to read the previous posts and review what's in them first.

    Also consider simpler solutions, like running a small rope from the house to the coop so you can open it remotely. Building a battery/solar-powered door that works reliably will be harder than it looks.

    With the work and time it will take to design and build one, you'd be far ahead by purchasing a commercial solution if possible.
     
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Last edited: Jul 30, 2011
  4. DrJack

    Thread Starter New Member

    Jul 30, 2011
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    Thanks for both of your replies,

    someonesdad - I did a quick 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. Plus, where is the fun in buying a commercial product? I am a poor medical student and they usually retail for £100+, which is a bit out of my price range. I doubt if the components inside them cost more than £10.

    praondevou - If it stays at that price then I will buy it, but I have a feeling that it will go up considerably!

    Thanks again,

    Jack
     
  5. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Oops, I thought it was a BUY NOW article, sorry about that.
     
  6. Ctenom

    Member

    Nov 1, 2010
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    Try looking up automatic curtain openers they would use very similar circuitry. And i have seen commercial timers for them.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    Well, you say you can get a 12v timer for £2.60.
    Where can the specifications for this timer be seen?
    Do you have a part number and manufacturer?
     
  8. someonesdad

    Senior Member

    Jul 7, 2009
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    Attached is a schematic of something I've been toying with putting on my coop's door. It shows how a DPDT relay could be used to control the power to a Harbor Freight battery-operated screwdriver to raise and lower the door. I got so far as to build a spool for the screwdriver and install the motor and door hardware, but I'm not overly happy with the Harbor Freight motor. I'm also worried about its behavior in winter temperatures below 0 deg F; I haven't tested it yet in those kinds of temperatures.

    I just came in from working outside in the heat, so I'm too pooped to check my schematic, which is untested. I don't know why I put the resistor R in there; I'd take it out now. Note DC motors like this are reversed by reversing the voltage polarity across them, which is what the relay does.

    Anyway, the relay and limit switches might give you some ideas on designing your own.
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    Well, the limit switches would be fine, but relays really wouldn't work for their application, as they are simply far too power-hungry.

    Something that really bugs me is that nothing I've seen so far is both energy efficient, and gives positive feedback to the humans-in-charge so that they are alerted if there is a problem; like the battery is getting low, the door is stuck, etc. with the exception of someonesdads' proposal of the rope and pulley arrangement. With all of the things life throws at one, it would be easy to forget about checking up on such things until it's too late, and you're missing a whole bunch of chickens.

    I'll digress here a bit, but someonesdads' reminded me of a project at a very high-tech company I was involved in some 20+ years ago. They wanted to automate the delivery of components from the storeroom(s) to the production floor, in order to reduce assembly time; so their was a proposal to install pneumatic tube delivery systems similar to what you see at banks to move money and hospitals to deliver medications.

    A justification for the size of the tubes was needed due to the additional expense involved in installing 8" tubes vs 6" tubes; so they wanted to know what percentage of the components used to build the various assemblies would fit in the two different sized canisters that fit in the tubes. We calculated something like 75% for the smaller and 85% for the larger, but also delivered our alternative proposal which was a trash can on a rope! 99% of the components and sub-assemblies would fit, it would cost about $100 and could be installed in about an hour by a handyman.

    Well, our proposal was ignored; they spent about $14 million and a year to install the automated systems; and right when they were finished the decision was made on high to move the plant.
     
  10. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Very interesting story. Well, it depends on your position and status if your proposal is being ignored or not, I learned that!!
    Sometimes they just don't want to listen to it because it's too simplistic or comes from someone who wasn't asked to bring in their own ideas.
     
  11. someonesdad

    Senior Member

    Jul 7, 2009
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    In other threads I've tried to explain to people that these "simple" chicken door controllers aren't all that simple when you have to account for the fact that a design failure or operational failure can result in the death of your birds -- and the thing may have to operate in environmental extremes (below zero to above 100 deg F here where I live). The inside of a chicken coop gets pretty dirty from the birds flapping around (feathers, dust, and CS). I've seen no designs (DIY or commercial) that give the feedback you mention. Currently, my feedback is a bike reflector on the door of our coop that lets me see from a distance whether the door is open or closed.

    We aren't overly attached to our chickens, but we are extraordinarily attached to one of our ducks, who is imprinted on humans and is our favorite pet. Both my wife and I would be devastated to lose this bird because she has so much character (it's one of those things you have to see to understand). Since our ducks are trained to go into the chicken coop every night, any automated door opening/closing design I would install would have to have my stamp of approval -- and I wouldn't approve until I had seen it operate without a failure for at least a couple of years.

    This is deeply connected to why my wife and I still manually open and close the coop, every day.
     
  12. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Here's just a start of an idea based on your requirements for reliable and dirty environment etc.

    Imagine a see saw on a bearing pivot, as a vertical panel. Like a 4 foot x 1 foot plank of wood, horizontally, but on edge. So when it seesaw pivots through maybe 20 degrees it either covers the entry hole or opens it.

    A decent sealed bearing (like a $10 car wheel bearing) would make it extremely reliable.

    Then a small container on the back of each side of the seesaw, filled with water, even with some antifreeze if you like.

    By pumping water from one container to the other you can reliably seesaw the door either way, and it will be stable in either position. It uses no energy when stopped.

    And here's the good point, you can run a couple of tubes back to the house and put a little water pump ($15 indoor fountain pump) and a valve if needed.

    So you can control if from inside the house. As there is no mechanism and no electricals etc in the coop it should be extremely reliable. The 2 hoses (1 hose?) from coop to house can be poly irrigation hose, cheap and indestructable.
     
  13. someonesdad

    Senior Member

    Jul 7, 2009
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    Hi, RB -- I came up with that one a few years ago too (although mine was just a counterweight that filled up to open the vertically-sliding door and was drained to close the door). I didn't like the fact that I'd have to use a 50-50 mixture of ethylene glycol and water in the winter (meaning I'd have to find a pump that would reliably operate with this material) and that there'd be a fluid that is tasty to animals but also poisonous (but that part could be handled by e.g. putting screens or nets over the containers). The other part is finding a reliable drain solenoid valve.

    It has the advantage of mechanical simplicity in the coop. But now the critical reliability area is the pump and solenoid valve. If someone knows of some good recommendations, I'm all ears. The other thing that would be easy to do is to use some microswitches on the door for the critical feedback that Wookie mentioned. Also, the fluid tank levels could be monitored with independent sensors and squawk if the state isn't correct at a certain point in time.

    Thanks for the reminder -- this method is now back under my thinking cap for my coop... :)

    One other thought: eliminate the drain solenoid valve by using something like a systolic pump that can be run in both directions? Ooohh, and these things are reliable...

    Here are some notes I made a few years ago about these methods:

    Water weights

    The simplest setup would just have a tube running to the coop. The next simplest setup would have two switches that indicated closed and open door; these would be used to double-check the operation.
    This would require a pipe to be run for the sensor switches and the fluid lines.
    A 12 V system could be used -- the pump could be a windshield washer pump. In fact, there could be two pumps in parallel for reliable operation. The fluid could also be a water and alcohol mixture.
    To avoid evaporation problems, a line could come back to the house that would vent the top of the container in the coop to the reservoir. Then the system could be completely closed.
    A backup mechanical timer could be used to provide an additional on-off signal in case the photoelectric detector didn't work. Or, there could be two independent photoelectric detectors.

    Hydraulic

    Similar to the water weights, except a piston would be used to provide the mechanical movement. The pump would pressurize one side of the piston to open the door and pressurize the other side to close it. The movement distance needed is 12".
    I could make this piston on the lathe with some 1.25" or 1.5" PVC rod. I have a 1" reamer that can reach over 6". If this rod was drilled with a long drill, then both ends could be reamed concentric with the first-drilled hole. A 1" diameter piston has 2.5 square inches of area, so to get 3.5 lbs of force, only 1.4 psi is needed. And we're only talking a volume of 30 in3 or 1/8 of a gallon of fluid to move. A small pump would handle this just fine.
    A nice feature of the hydraulic is that the motor can be run until the motor current increases to a set value, indicating the piston is at the end of its travel. This could obviate the need for limit switches (or they could just be used as a check to set an alarm if they aren't properly indicating).
     
    Last edited: Jul 31, 2011
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