Electronics > Projects, Designs, and Technical Stuff
Automatic chicken door time input (low power, simple)
Ian.M:
Wasting a whole air cylinder for the deadbolt does strike me as a bit excessive, but if that's what you've got, then why not? Its certainly better to have a well proven mechanism, and 16 months of successful operation qualifies. I would recommend adding some sort of 'trapped chicken' sensor on the edge of the door or doorway that stops and reverses the door if there's any obstruction while its closing before it reaches the fully closed position. A dowel mounted between the levers of two lever arm microswitches such that the vertical edge of the door just clears it when closing might be suitable, though as the door has a raised threshold, you should probably put a sensor for the bottom edge as well.
As it isn't an outbuilding there's no point in trying to economise on power consumption past what's simple and easy. There's mains power available not too far away so simply float a SLA using a traditional linear supply for long life and reliability to power it all and concentrate on improving the algorithm for the door open/close times and the UI for adjusting it. Any electrical system with stored energy is a potential fire risk, but a suitably fused low voltage one is a minimal risk due to the low energies involved and the greatly reduced risk of insulation breakdown.
On the UI side of things, why not move the Arduino down to a reasonably accessible position and fit it with a RTC module, a LCD shield and some buttons to emulate the operation of the mains timer that your users are already familiar with?
None of the chicken sensor ideas appeal to me apart from individual RFID leg rings. That + two readers inside and outside of the door just far enough apart that they don't interfere with each other, so for any specific bird, if the inside sensor was the last to see the tag, you know that bird is in, and similarly for the outside sensor and out. However, as I mentioned earlier, doing anything except raising an alarm if one is missing at closing time is counter-productive. You still need to close the door to safeguard the other birds, and certainly don't want to open the door again during the night for a fox with the tag in its stomach.
Amper:
Yep, the second cylinder is excessive, i would not have done it if i dint have a dozend laying around with no use anyways. Im pretty lucky to have a good source of free "scrap" like that so it was no concern to overdoo it in that case. Also this way i didnt have to make any mechanics like deadbolts or latches, just put the cylinder there with a few more screws. It also made the controls simpler the sequence of locking and unlocking is done by a single pneumatic momentary switch on the door, when pressed the locking cylinder is activated, when not pressed (open door) only the moving cylinder is supplied so they can be operated like a single one. Also no cables and plugs that require soldering in the cold and dirty barn, polyurethane tube is cheap and is replaced, shortened or extended in a matter of a minute or two with no tools required, it will also survive being pinched in the large door or ripped out by accident. The trapped chicken sensor is not really necessary as i only supply roughly 500mBar wich translates to around 15N in the cylinders used. After having the geometry of the linkage there is no risk at all of hurting any animal. If i used high pressure supply id just add a pressure regulator (thanks scrapheap of my university :-+) and limit the force that way.
economizing power mostly is just a wish of mine, it just feels wrong to have something plugged in all day without doing anything. Also as said before im a bit paranoid about anything grid related. Cheap chinese switch mode supplies are actually the number one cause of house fires in my country and i didnt have good experience. I have Industrial 24V supplies but they are overkill and have quite a lot of standby power. The next socket is almost 10m away and i would have to run ducting over the wall and ceiling to reach it, so while its possible and im doing it that way at the moment im just not happy with this situation. A small cap bank of some few hundred joules to survive a few days with no sun would be ideal. Its low voltage contained in a housing, fused, cant leak, wont freeze and should last a few decades without degrading.
One idea you just gave me by "simulating" the old UI is actually to go back to the simple way of using pots. The old one is mechanical, so its similar and thinking about it, it has incerements of 15 minutes. The atmega will have roughly 90s of resolution when i spread 24h over its entire range, so thats plenty fine enough for my application. Previously i thought for good resolution id need four pots, one for minutes and hours of each set point but i dint even bother estimating if one would be sufficient.
tpowell1830:
Ok, so you want simple, got it. You could set your timer up to go for 12 hours then open the door or if solar panel sees sunlight. The start timer could be a simple limit switch when the door closes. The test is to see if there is sunlight on your solar panel (connect the panel with a schottky diode to the caps or battery), take your 'sunlight' voltaage reading on anode side of schottky, for reading from the solar panel when it starts charging. If it sees sunlight, open the door and reset the timer to start when door closes again when it is dark. You can adjust the 12 hour timer to whatever it is in your latitude for night time hours (or adjust twice a year).
Hope this helps...
cdev:
You could use Raspberry Pi "deep learning" based object recognition software to identify and count the various animals,as well as keep track of the time, actual brightness, etc. You could use a body of photos of your actual chickens, as well as photos from Google Images of foxes, hawks, dogs, as well as permitted humans, and others, to train it.
Then you might be able to use that data to decide when to close or open the door or raise an alarm, or even blink flash tubes. It could also send an SMS to you and other family members to tell them if any of your known chickens were missing from the coop, or if any recognized or unrecognized animals or humans, even, had been seen, along with photos of them.
Note: as my post was originally making the same suggestions as had been suggested earlier, I edited it.
Amper:
Guys really, i appreciate you giving me advice but have you read even a bit of what has been written previously ?
I really dont want to offend because you are all really nice and stuff but we have been talking about rtc, time calculating and light sensing all day long now and you suggest it to me like no one has ever thought about it before? i dont expect anyone to read through all of the posts but you could just go "CTRL-F" and search for "RTC" before posting if you havent read the old posts.
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