Automatic Chicken Coop Door - Auto Closes Coop - Beta Version 1.0

[Sappy]

Quote:
Just opening and closing a drawbridge door each day, and powering some timing circuits, would be a pretty modest power drain. I don't think we'd even need a motorcycle battery to do it. Some rechargeable C or D cells might even work... but with the cordless drill you don't even need that. You'd already have all the rechargeable battery you need right there.

Harbor Freight stuff is normally pretty cheap, you do get what you pay for, but you can make it work if you don't expect too much from it.

With the light-sensing system I'd like to do, I figured I'd put it on a time delay. Make it close 15 minutes or 1/2 hour after dark, and open 15 minutes or 1/2 hour after dawn. That might get into more technical stuff than most on the thread want to deal with though.

 

[aiwetir]

i only mention the motorcycle battery because it occurred to me that you can just hook up a cheap harbor freight batter charger and never have to think about it again (hopefully)

i'm not sure how much a solar charger for a ni-cad drill battery or some d cells would be or how to hook it up to charge and run at the same time.

for me, i still haven't decided if i'm going to close the chicken door or the man door. man door is better as i don't have to go open the henhouse door at any time, chicken door is better as it's smaller and easier than the man door (and it's easy for me to change the chicken door at any time, i'm pretty committed to the man door's installation)

 

[Sappy]

Quote:
THe motorcycle battery is a good idea, don't get me wrong!

Might be like swatting flies with an expensive hammer though. When I design and build my system that might be what I do, since I want to do some other stuff besides just open and close a door. I've thought about a small ventilation fan for the hot months, powering an electric fence at night, heated water dish for winter, automated feeder and waterer for when we're away for the day, lots of things. I'm not sure how much of it I will actually do, or how much of it is even feasible to do at this point. Like I said, all just ideas til I actually get moved, get chickens, and get the chance to put something together. I'm sure with some of that I'd be reinventing the wheel, or thinking of things that I'll later discard as unnecessary or poorly thought out.

Another idea I've had lately, after watching some threads on incubating where people had power outages, is an incubator with a battery back up and two heat sources. I'm a born tinkerer, that's why i'm a tech. I just can't manage to leave anything alone. *laugh*

 

[aiwetir]

yeah i would look into a heat source backup if i were going to incubate.

i'm not going to though, no roosters allowed here.

 

[CedarLake]

Dave:
The motor I have is much bigger than the RadioShack ones. However, I think using a cordless drill is an excellent idea. Reversing is easy and can be done with a double-pole double -throw relay. I'll post later on how to hook up such an animal (in a rush to get to work right now!)

I'm using an emergency- light battery. It's a 12volt lead-acid rechargeable and they are cheap on the surplus market (I love buying from surplus electronics dealers cause the prices are amazing). Right now I have designed a circuit that can use two inputs or pushbuttons. Activating one input will run a motor in one direction for a few seconds (adjustable) until it hits a limit switch or times out. Pushing the other button will run in the opposite direction. I need to test my design and then I can put plans up on my site.

I used to do this stuff for a living and now it's more fun doing it as a hobby.

I'm also using the battery to provide supplemental light to the coop for a few hours at night to keep them laying as the days get shorter. The light is already built, but needs a timer.

Something like that is perfect to be activated by a timer that can also set open & close times -- that will be my next project

 

[Nifty-Chicken]

Great discussion everyone! Please don't worry about the technical discussion as there are obviously a good number of us here that have experience enough to understand and contribute!

The cordless drill is definitely the cheapest / strongest and best solution if you are going with a screw drive based opener / closer. The benefit that it comes with a battery installed is perfect.

Regarding charging: The Harbor Freight panels that are $7-$12 would work fine. Remember, you only need enough power to turn the motor for about 30 seconds to 1 minute... plenty of sun in an average day throughout the year to provide enough amps to do this. My friend at the Lab has worked with me to design a constant current circuit and a boost circuit that could be used to modulate or bump up the power from the panels.

What a great discussion!! Keep it going!

(By the way, seems like we have a few electronic geeks... now where are our mechanical engineers to design the perfect door and screw drive?)

 

[Sappy]

Quote:
I used to get a lot more enjoyment out of electronics when I did it as a hobby, funny thing that. When it's your bread and butter you want to get away from it in your spare time. I'll be doing more electronic tinkering when I move home though, and might do some in the mean time til then on a few small projects I can accomplish with limited space to work in here in this tiny apt.

Since I can get a little more technical now, how about just using a flip flop along with the electrical contacts on the coop and door as I mentioned earlier. The flip flop would be toggled by the pulse that tells the circuit "time to open" or "time to close".

Let's also say we had another contact, raised off the ground in front of the coop a bit. When the circuit signals "time to open" the flip flop is toggled, the drill starts to turn and the drawbridge door is let down, eventually the contact on the lip of the drawbridge meets the contact raised off the ground. That stops the drill motor. I'm sure we could also find a way to have a "bridge is down" contact without having the contact on the ground too.

When it's time to raise the drawbridge, the "time to close" signal is generated, the flip flop is toggled and sends out a pulse and turns on the drill motor moving in the opposite direction, the drawbridge is raised until the contact on the door's lip meets the contact on the coop.

Using this type of system, if something tried to open the door at night, the door would just try to close again as soon as the door wasn't making contact with the coop. The circuit would be pretty simple, and wouldn't draw much power at all itself. The flip flop and a few basic digital gate ICs would be sufficient, and a couple transistors for relay drivers maybe or a solid state relay.

This is separate from consideration of the actual timing circuitry... the alarm clocks, timers, or light/dark sensor. We can tackle that separately depending on how people would want to manage their automation.

Dangit, I wish I had a program on my computer that would allow me to draw circuits and export them as jpgs *mutter* Need to look into that.

btw folks, there's a place I deal with locally here, and I mail ordered from them when I lived in the midwest. www.allelectronics.com They have pretty good prices on things, and are generally a better option for parts than Radio Shack. I've found a lot of Radio Shack's parts to be cheap junk over the years. I don't even go there anymore unless it's the only option in an emergency. I saw someone else mention some surplus places they deal with and get good prices from. I'd be interested in seeing links to their websites.

 

[Sappy]

btw, regarding reversing the drill,I just realized, if we're using a flip flop we could probably dispense with relays altogether and just use a couple transistors to switch the drill direction. Just hook a beefy enough transistor or FET up to the output of the flip flop and use them as the switches. That eliminates depending on electro-mechanical relays, simplifies the circuit, and would be more reliable. Cheaper too.

 

[Nifty-Chicken]

Here is who I use for my bits: http://www.jameco.com They have pretty good prices and diversity.

I've had PCB's printed before and know of a GREAT deal on them if we go down that path.

For drawing circuits, I know some use this: http://www.cadsoft.de/

Simplicity would be key and I think having a photo resister would be a good way to go if you could dial it in exactly to what you want... also, having it drop the door 15 mins. after the photo sensor triggers is definitely doable. My buddy had these working already as two circuits, but I'm sure it would be pretty straightforward to combine them into one circuit. Light sensing would be super simple / easy if it could really trigger at the correct time and not have a false trigger (which I think is very doable if set at a really dark setting). Getting away from the timers, multiple on / off times would be good.

 

[Sappy]

Quote:
The time delay is really easy,that's a circuit called a "one-shot". It can easily be built with a 555 timer and just a couple resistors and capacitors.

Light dependent resistors might be a good way to go as a light sensor, or a photo transistor, or even the solar panel if a person wants to use the cheap battery tender solar panels to power the project. There are a lot of ways to skin that cat. The most straightforward would be to use a comparator circuit to compare a voltage across the photo resistor or other sensor to a voltage reference. A comparator is basically just one stage of an op amp IC, and it's only job in life is to compare two voltages on its two inputs, and swing it's output high or low depending on which voltage is higher.

Combining simple circuits is all that most design work really is. You break the job down into simple building blocks, design a circuit for each one, and then combine them into the whole.

I've dealt with Jameco before, check out All electronics, their prices are usually better. Jameco will have a wider variety of components though. I'll check out the software you gave a link for, thanks!

- Scott

PS - Anybody in Eastern Missouri or Western Illinois between Quincy IL and St Louis MO? That's where we're headed when we move. I might be interested in swapping my labor on a setup like this for some chicks, hatching eggs, or something when we're settled next June.