Now that I have retired with spare time on my hands, I thought I would tackle what has been an ongoing problem for me over the years – keeping my chooks safe at night from predators, namely foxes.
Seeing that they mostly attack at night, I set about making an automatic chook door that would close each evening and re-open the following morning at sunrise.
There are many D.I,Y automated door openers on the web, so here's yet another. Most of them use timers to do the job, so I am guessing they would need continual adjustment as we pass through the seasons, or the chooks remain locked up for a period of time in summer when there are more daylight hours.
There is about a four hour difference between summer and winter daylight hours where I live here in Brisbane Australia, so I set out wanting to use a photo-electric cell to do the time adjustments for me.
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Step 1: My Three Most Common Pests/Preditors
As well as being bothered by Foxes, there was the odd carpet snake that would snack on my hens, and the ongoing problem in dealing with rats and mice.
All these predominantly show up after nightfall, so while I was fox proofing my coop, I thought I could also minimise the other two by replacing the wire mesh with a finer one to keep these out as well.
Step 2: Sourcing the Materials
I began by sourcing the materials that i needed from EBAY.
All the items above are not overly expensive. You can get them cheaper from China, however cracking to get started, I wasn't prepared to wait weeks for them to be shipped, so i paid a little extra and obtained them from local sellers. All up, it probably cost me around $50. 12V Car Aerial, 12V 5amp Computer laptop power supply, Dusk to dawn Photo-electric cell and a Delay relay switch. All the other components I had lying around in the shed and yard.
Step 3: Assemble Components
I'm relatively new to the Instructables web site, so don't have any details to show the assembly phase as I had already started on the project.
Anyhow, it's just basically banging a few boards together to make the frame. For the door assembly, I tried the vertical lift but found that it placed a fair load on the motor. I eventually settled on a horizontal slide using a draw slider (with ball bearings) mounted at the top to reduce friction. I recon if I had one at the bottom as well, it would clog up with dirt, sawdust and poop over time.
The distance the aerial travels needs to be adjusted to suit the distance the door has to travel between the open and closed position. I found this excellent article written by J Ballone on the net which describes in detail how to go about making the alteration - thanks JB.
Step 4: Testing Before Installing
OK, now for the big test before I go about installing this in my coop.
There is a few seconds delay before the door is activated after the photo-electric cell (PC) triggers.
Nightfall is simulated by covering up the PC.
The video above shows my door in action.
Step 5: Curses...Got a Problem.
Because my pen resides under many trees, I found the door was closing prematurely due to the heavy shade as nightfall approached. This was locking my chooks out of their coop before they had headed off to roost for the night.
So what I did was to install a delay relay switch to postpone the closing of the pen door by about 30 minutes.
The way the aerial works is as follows:-
With just the black and red wire connected to the power source, the aerial is in the retracted position, which means the door to my pen is open. For the aerial to extend and close my door, there needs to be power supplied to the green wire.
In the attached video, I have wired up the relay to delay for about seven seconds ( for demonstration purposes) before allowing power to the light - The light representing my aerial once I have incorporated the relay into my wiring.
With this particular relay module, the delay period can be extended to up to one hour by reconfiguring the jumper switches and adjusting the potentiometer as described further on in the following step..
The green LED will light up for the duration of the trigger time that has been set (7 seconds).
The light now switches on and will remain on (meaning my door will remain closed) until the photo-electric cell triggers again the following morning.
Step 6: Configuring the Delay Relay Timer
Here's a description on how to configure the jumper pins to set the delay for the desired time.
Step 7: Wiring Up Components
OK, so here is the complete wiring diagram on how I configured my setup. You could of course use a 12V battery, but i found that it required charging every 3-4 days which would be a pain in the butt for me. A solar charger was also out of the question due to shade, so i went with running mains voltage out to the pen.
I'm a complete dummy when it comes to wiring up and understanding electrical circuits. The photo-electric cell (PC) and delay relay came with no instructions what soever. I have only basic school boy knowledge, and could not find anywhere, a decent instruction on how to wire up the relay with the PC. So after a fair bit of trial and error I was able to put something together and finally came up with the following solution. Hopefully this will help others like me who are also not electrically minded.
Step 8: Other Enhancements
After installing and having it running for a while, I thought it would be handy to have an override switch on the door so as I could manually close the door during the day if needed. Certainly helps when trying to catch the little blighters.
The switch I used is a SPDT type, which allows the current to flow in only one of two directions, but not both at the same time - i.e. Current to flow to the aerial either via the PC and relay, OR directly from the power source.
You need this type of switch to isolate the relay from receiving a current backflow into the output end of the device as it sends the device into a panic attack.
Above is the switch and the wiring if you are interested in adding this. The switch cover is just a cut out plastic bottle to protect it from the elements.
As the old saying goes "you get what you pay for" and seeing as the Photoelectric Cell only set me back a few dollars, i wasn't sure of its robustness, so I enclosed it in a jam jar to protect from the weather, dirt and insects.
Happy chook keeping.