Having had chickens for around 4 years, the novelty of going out to them every morning has worn off a little, it became apparent that a little automation would help improve our sleep time as we would not have to get up as early. Chickens can be quite noisy - if they think they should be out and you have forgotten. So, some automation was necessary, but loads of people have done automatic pop hole door openers and closers, that would be boring and you can go and buy one for around £70, how could this be made more useful and interesting ?

It can't be that hard either, a couple of weeks should have it sorted, or so I thought.

To get things kicked off, we needed to know what we are trying to achieve, so a functional spec was needed. We settled for the following basic specification that we can build onto over time.

Must Have functionality

The system must :

1. Not hurt the chickens
2. Help to keep the chickens safe
3. Be able to tell us when it has a problem
4. Be weatherproof so it can work all through the year
5. Be reliable
6. Automatically open and close the pop hole door at the correct times
7. Have the ability to lock the main door closed and open
8. Require minimal human involvement – except filling food, water and collecting eggs etc.
9. Automatically charge the system up from solar electricity
10. Indicate if the hen house controller is OK or has a problem, so that we can fix it
11. Have the ability to light up the bottom of the hen house so that we can illuminate rats, so we can shoot them. Rats bring disease and eat the food.
12. Have a chicken Night Light inside the house to aid roosting (the bars are up and chickens are not good with low light levels)
13. Have a manuall override the system to lock the chickens in or to let them out – locally from the hen house
14. Be Fox proof
15. The system must not compromise the security of our house or network
16. Not make the chicken house look ugly  

Nice to have functionality

1. ChickenCam – to see what they are doing – from the house so we can watch from the iPad
2. Outside light for winter months – to give increased egg production time.
3. Fox detection at night. This will need an alarm of some form, but it must be able to differentiate the family dog from a fox.
4. Some way of keeping the chickens warmer in the cold months – but without setting fire to the hen house.
5. Make it easier to maintain the chicken house 

So, now we know what we are trying to do, how are we going to do it ?

1. We need to know the time of day, and when to open and close, but that changes every day through the year
2. We need to be able to sense when things go wrong, or when they have finished successfully, for example moving a door, unlocking, locking, etc

We also have to think about the potential problems

1. We should not rely on a light sensor, since passing cars and people with torches would wrongly make the hen house think its morning and open. We use a torch when we go out to the house after dark for example.
2. There is no external electricity supply – so it has to work with only the energy we can harvest.
3. It helps if we know the temperature in the hen house / outside the hen house
4. A chicken house is basically a large tinder box - dry wood and dry straw, so we need to be careful about heat and failure conditions. After all, we don't want roast chickens. That wouldn't go down well with domestic management ;-)

We also take a design decision that we will obtain sub-assemblies where we can. rather than make everything from scratch, since there are loads of little boards, gadgets and gizmo's that are now in the market that are available for next to nothing in many cases. Lets use them to get the project going quicker.