Chicken door opener ( not pop hole )

Hi all I am very new to Arduino and wonder if someone with more experience ( which will be all of you) could offer some advice on if this could work.

Not wanting a pop hole opener ( as seen on the forum, a motor lifting a door ) my wife who has 3 chicken houses the main one is in an enclosure which is opened during the day.

I want to set the arduino up so the main gate on the enclosure opens at a set time (RTC I suppose) within a set time after that the first door opens ( I thought about using an electronic lock £5 ebay) this and a gate spring would swing the door open ?

Using the same type of instruction a 2nd lock and door open on the next chicken coop and lastly the 3rd chicken coop. the first and 2nd are quite close the other is approx. 40 feet away

Is this feasible the locks I have seen on Ebay are 12v, Ideally I would want this run off a 12v battery and solar panel to trickle charge ( or is this just too complicated ?) These were my thoughts once I am more confident but thought I would ask now for advice. I didn't want to go down the levels of light etc just set to open at a specific time each day with the RTC I assume when the clocks go back this is easy to programme in.?

You will note I have said nothing about closing them up at night, my wife likes to make sure all the chickens are away so it will just be a case of closing the door ourselves. As you can see from my description I am very new to this. Any help would be appreciated. Cliff

I know you say you dont want it to work using light but from a programming stand point, it would be a whole lot easier to use a photoresistor to open a switch rather than setting up a timer. You would just set a pin as input and when the sun comes up the photoresistor would increase voltage. When the pin voltage reaches a certain point you would use another pin to open your door. Real simple.

That sounds like a good scheme. Slightly unusual that you don't want to close the gate but you have a good reason for doing it that way.

You requirement for 40feet needs a little thought. Laying that amount of cable in the ground is more expensive than you might imagine. If you don't mind repairing it from being hit by the mower occasionally then you don't have to bury it deep. For just a 12V power signal going to a solenoid, you don't need to worry about interference or lightning strikes. You should find an online calculator for the voltage drop along the wire. You will need to know the current that the lock uses and the minimum voltage. For example, with a particular size wire and current, you may need to put in 13V at one end to get 11V out the other end. Or buy thicker wire.

Consider a relay shield or a MOSFET shield to switch the 12V to the lock actuators. You will definitely need an RTC and a power supply that is able to deliver enough current. A small lead acid battery and a solar cell about 0.25-0.5 square foot would probably be sufficient.

Thank you both for replying all points noted the cable run would be fine as I have a big garage between the coop and the cable could run inside. I didn't realise how simple the photo cell would be and so happens have just ordered 50 from china along with 3 RTC's and lots of other bits. I think I need to look into this more but when it's decided I will post back with results.

Thanks again Cliff

MorganS: That sounds like a good scheme. Slightly unusual that you don't want to close the gate but you have a good reason for doing it that way.

Absolutely excellent reason.

The last thing you want is to lock chooks out.

For this application, you could probably do it with a photocell and no RTC.

The Arduino resonator is a lousy time-keeper, but you can write phase-lock-loop algorithms to keep a rough track of the time so that the gates only open at "daylight" within a certain expected time but the "clock" also corrects itself according to that daylight time, day after day.

Somewhat like the algorithm the microcontroller in your fridge uses to defrost when it knows you are not going to open the door overnight. Or do you?

Thanks Paul, I have decided and will go down the photocell route.

Cliff

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