Monthly Archives: July 2013

Automatic Door

A Better Automatic Chicken Coop Door

For those who have chickens in their yards, a reliable automatic coop door is the holy grail. The end of constant fighting over who will go outside to close the coop…the end to dreading that you’ll forget to close the coop and inadvertently fatten a local raccoon while traumatizing (and downsizing) your flock.

After about a year of having our chickens in a tractor-style coop (they are always enclosed in the coop, but you move it around), we decided to just let them free-range. Thus, the coop-closing issue was born. Soon after I decided to take a look around at the state of the art, see what other chicken keepers had used to solve this problem. Reading forums and watching videos, it seemed like the market was full of expensive solutions or garage-built ones. I wanted simple, effective, and less than $200.

I’ll skip the gory details, but it was a disaster. It often was stuck open, and just never worked right…even after significant re-design. The winding-a-string method of moving the door coupled with trying to slide a door in a simple notch left lots of room for malfunctions.

After a year of fiddling with the off-the-shelf door, I was determined to make something better. Something more reliable, where you’d never have to worry about the door getting stuck, where the door was actively held down when closed so nothing could pry it up and get in.

I ended up with the design you see in the pictures. I recently installed it into a new coop. Instead of a motor winding a string, I used a linear actuator. The improvement here is that you’re still using a motor, but that linear actuators can have a static loading capacity. This basically means that when the actuator stops, it holds whatever its attached to in place (so raccoons can’t just slide it up, for example). Linear actuators, in addition, often have position-limiting circuitry built right in…no more hodge-podge limit switches exposed to the elements.

WARNING: if you make a similar door, make sure you pick an actuator that is both slow (1.5 inches per second or slower), and relatively weak (15lbs force or less). We don’t want to create a chicken guillotine!

The second breakthrough was the use of a cheap drawer-slider to aid in reducing friction of the movement of the door. The sliders act as a track, keeping the door in place horizontally, and the wheels on the track allow for very little friction as the door moves up and down. I used the simplest (and cheapest) type of track-slider, the ones with small nylon wheels in them…I was afraid that the bearings in more expensive models would get fouled (no pun intended) by being outdoors and exposed to the dust/dirt.

I’ve got a video walk-through of the door installed on my old coop:

The control circuitry is based on a couple of wildlife feeder timers that I happened to have on hand already. These are designed for remote (solar) installations, so they are very low power. They simply trip an internal relay for a user-settable duration at up to 6 times per day. They have four wires, two connect to the power source, and two go to the device to be controlled by the timer.

Usually these timers just control a simple motor that spins in one direction. With this linear actuator, however, we need to spin the motor in both directions: one way to open the door, the opposite way to close the door. With motors, reversing them is as simple as reversing the polarity of the power-source, but achieving this with these off-the-shelf timers requires some external circuitry. Below is a diagram (while it looks complex, it really is quite simple).

Control circuitry

The single-pull double-throw (SPDT) relays control the polarity going to the actuator based on which timer is activated.

Here are the key parts:

  • Timer units (2 @ $30.00)
  • 12V actuator (1 @ $110.00 – the actuator I used is discontinued, this one is equivalent)
  • Actuator mounting brackets (2 @ $10.00 – these seem expensive for what they are, feel free to experiment and DIY)
  • 18 inch drawer slider ($7.50 – also available at hardware store)
  • Perf board for control circuit (5-pack for $7.00, you can get singles at Radio Shack)
  • SPDT relays (5-pack for $6.00 – also available at Radio Shack)
  • Wire terminals (5-pack for $6.00 – also available at Radio Shack)
  • Solar Panel and Charge Controller ($35.00 – only if you’re going to use solar to charge a battery-powered install)
  • A 12V battery. A car battery is expensive and is probably overkill unless you live in an area where solar power will be unreliable. I use a lawnmower battery that I had from a previous project, but you could use an even smaller one.

So, all tolled up this is more in the $250 range, however, I did already have the timers and the battery on hand so I slid in at less than $200 in new expenditures  The increase in reliability is well worth the extra effort. The door has never failed, caught a chicken, or gotten stuck. I find that I have to adjust the timers for changing daylight once every couple of months, which lets me check on the battery charge level at the same time (the timers show battery voltage).

Coopsicle, Austin Style


In the 6 or so years that I’ve had chickens, we’ve moved three times (such is the life of a student). Now that we’re paying a mortgage, I wanted to build a coop that was well thought out, comfortable for the birds, and that actually could be counted as an improvement to our backyard.

One day while browsing a google image search for “chicken coop”, I stumbled upon a really cool looking coop:


Turns out this is the Coopsicle design from a book by Kevin McElroy called Reinventing the Chicken Coop (Kindle version). I read some reviews and downloaded it to take a look.

Setting the coop on a single post lets you easily put this coop on uneven ground, and we don’t need a fenced in run since we let our hens free-range in the backyard. Last weekend I sat down and really thought about how I could modify this coop for our set-up. Here’s the result:

Coopsicle, Austin StyleThe original coopsicle was located in northern California, where the summers are more mild than ours here in Austin. As such, their use of two re-used windows in either end makes a lot of sense and looks great…but we would need more airflow. I replaced the windows with 1/2 inch hardware cloth. I didn’t have any that would have spanned the entire 36″ x 36″ opening, so there are two panels with a divider. I’ll probably get a couple of plexi-glass panels to cover the openings during the winter months.

The end panels aren’t structural to the coop, so I made both of them removable to make cleaning the coop easier. They attach by sliding over two 5/16″ carriage bolts (one on each side) and are held in place with wing-nuts. In the picture you can see the recessed nut that lets the door sit flush when it slides over the bolt.

I kept one of the doors as designed, which allows access to the nest-boxes and the food. The other door I replaced with my previously built automatic coop door. Luckily this coop design is tall enough to accomodate the existing linear actuator I used, so it was pretty much a plug and play install. Check out the post on the door opener for more details, its been working great for over a year now, and is much more secure against predators than string-based designs. I chose to put the automatic door on the side of the coop you can easily see from the house so you can check on it with a quick glance. On the other side of the coop is a pop-open panel that gives easy access to the wildlife timers that set the opening and closing times

I put the coop lower on the post than the design called for in the book, and I used a 4×6 pressure-treated post instead of the 4×4 post they use (both modifications they recommended for increased stability). I really wanted to use a 6×6 cedar post, but I couldn’t procure one in time. The coop is still high enough to let me hang the 3-gallon fonts. Hanging them seems to keep the trough more full than sitting them on the ground. We use 2 just to be sure the girls have water when we go out of town for a few days.

In the book, Kevin calls for a thin-gauge aluminum roof. I kind of like the look of rusted steel, so I opted for 16 gauge steel instead. 16 gauge is a bit thicker than most roofing metal, but it is thick enough so that it won’t bend under it’s own weight. It should also rust nicely while staying structural and straight. I chose to make the roof overhang a bit further than the design in the book calls for. There were a couple of ramifications to that decision. My 6″ overhangs meant that I had to get two pieces of steel to do the whole roof (sheet metal only comes 48″ wide where I buy it). I chose to get 2, 26″ x 84″ pieces and join them at the peak of the roof with outdoor caulk. If I had a welder I would like to have welded them up, but I don’t so I didn’t. We’ll see how the caulk turns out.

The last change was that I didn’t do the circular stairs like they do in the book. My automatic door would have been difficult to turn into a floor-opening, and having a solid floor makes clean-up a bit easier (in my opinion). I put a jump-up platform under the door, and built a ramp to help them get used the the new digs. Its a bit high for our oldest hen, so I’m going to have to lower the platform if I want to remove the ramp eventually.

I’m really happy with how it turned out, and I’m thankful for the inspiration Matt and Kevin provided in their book.