Ultimate Chicken House - Phase I - light sensitive automatic door

A little while after we got the chickens, the evenings were starting to draw in and we realised we'd soon be back from work in the dark. We were keen to allow the chickens a free range in the garden as they don't like being 'in the cage' all day. A technological solution was required...

Surely there would be plans for a project like this on make? Unfortunately not. If time had allowed it would have been great to build a system from scratch but the evenings were drawing in too fast. We therefore opted for a commerical model from the rather limited range available. Phase I of the ultimate chicken house is a simple description of the installation of the light sensitive automatic door and a review of its operation.

the kit

After some considerable searching for a model available in the UK I found the VSB Electronic Door Opener. It is built by AXT Electronic in Germany and I bought mine from Wells Poultry Housing. I love the animation on the AXT website even if it does look like the chicken is about to be guillotined!!

The VSB kit has several variants and I didn't find the information on the web that comprehensive although an email to AXT was answered quickly. The VSB comes in an indoor (VSBi) and outdoor (VSB) version, the only difference being the outdoor version has an integrated light sensor whereas the indoor version has a light sensor on a cable (approx 80cm). The opener works by activating a motor with a spindle around which the 'string' is wrapped. The string therefore pulls the sliding gate up (or reverses to let it down) depending on the light conditions. Metal sliding gates can be bought as well as an idler to allow multiple gates to be lifted at the same time. The motor/string have a 40kg limit which seems impressive given the small size of the unit. The other impressive thing is the battery life is supposed to be 3 or 4 years from a set of 4 alkaline AA batteries!

In the photo above you can see on the left hand side the path the string takes through a horizontal spring loaded slider which provides feedback to the unit on the resistance on the string. This allows the unit to detect when there is an obstruction such as a chicken in the path of the gate and causes the motor to stop. Centre bottom you can see the potentiometer that allows the light sensitivity of the unit to be adjusted.

the house

My chicken coop is the P&T Poultry 6 Bird House - our 2 bantams are therefore living in luxury! The advantage of this house is that the sides (including the side with the nesting box) unscrew in a few seconds via a couple of bolts with large plastic caps. This makes it easy to get in to it for cleaning and installing the technology that the modern chicken demands.

the installation

The are 2 ways to do this - external installation or internal installation. I bought by house because I liked the look of it and so mounting the VSB on the outside was not an option. The design of the house doesn't allow the unit to be screwed directly to the wall. There were some extra batons that came with the chicken house and so I used these behind the top of the VSB and the top of the gate (see photo at top of page).

Now, as every man knows, keeping odd bits of wood is of vital importance. My wife is constantly trying to empty the shed of my bits of wood and I am constantly trying to sneak them back in. In one of those (admittedly rare) moments, one of my bits of wood was absolutely perfect for the job of filling the 4 inch gap between the sliding gate and the door frame. Having mounted the sliding gate to the right side of the frame (as viewed from inside) I screwed my piece of 'tongue and groove' to the left side of the frame and the 'tongue' fitted neatly into the outer groove of the metal guide rail.

My main concern was whether the metal gate was installed securely enough to resist being bombarded by a determined badger or fox. It feels a bit light weight but being metal it is no doubt strong. I think the weakness is in the fixing of the guide rails as they only have a hole at the top and the bottom. Any twisting action might enable the gate to be pushed out. It is difficult to get the lower screw to hold as the bottom of the door frame only comes about half way up the lower screw hole. I might make a few more holes in the guide rails in the future.

The next stage was to attach the string to the gate. The string has a loop on the end of it which is poked through the hole at the top of the gate and I used a nail through the loop on the other side of the gate to secure it (see above). It's important to get the unit and the gate aligned well. On my first attempt the string kept snagging on the VSBi's aperture resulting in the gate stopping only half shut.

The final part of the installation was to get the light sensor in the right place. This took some experimenting to find the optimal placement - not in direct sunlight, not too far in to the darkness of the house.

The unit is 'set' by attaching the gate to the string in the 'up' position and then inserting the batteries. The gate then descends to the lowest position and the 'stroke length' is therefore recorded. The unit then presumably knows how far to wind in the string when the door is coming up.

So, in operation...

When it gets dark, the motor slowly unwinds the string until it reaches the predetermined length. If an obstruction is encountered the line goes slack and the motor stops to allow the chicken to escape with its head intact.

When it gets light the motor winds up the string and lifts the gate.

Problem: in the summer it gets light at perhaps 4.30am when mr fox is still around.

Solution: 1) Use the BS battery powered timer which fits on to the VSBi. This can be set to allow the door to be opened only if it's after say 8am. 2) If you are around, close the outer door at night and let the chickens out when you want. 3) Build a DIY timer device to connect to the VSBi unit (see Phase II).

The VSBi is a well designed piece of kit that performs reliably. The battery life is excellent particularly as it uses standard AA cells. It's certainly not cheap but then this is a piece of mission critical technology.

pros and cons of automation

Prior to installing this system I was advised that automatic gates on chicken houses aren't a good idea - they don't work and they lock the chickens out and the fox in. I'm sure there's considerable truth in this but all I can say is - it works for us. We can go away for the weekend without getting a neigbour to lock the chickens up at night. Likewise with going out for the evening. When we're around we lock the outer door for added security. There is a theoretical risk a determined predator could somehow push its nose or paw against the gate and lift it up but having tried this myself it's not easy (although not impossible).

The most commonly asked question is how do the chickens get themselves inside before the gate comes down? Well they have always taken themselves off to bed at a reliably consistent time before darkness so this didn't seem to be a problem. Around November though when it got dark much earlier I did find Millie locked out a couple of times. By adjusting the pot (about a 1/3rd turn) the gate became less sensitive giving them an extra 15 minutes or so to get in and we haven't had a single lock out incident since then. That is with the exception of one night when I found them asleep on the windowsill. The autumn winds had blown the outer door shut and they couldn't get in. We therefore use the water container as a door stop now.

Automatic door opener installed internally

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