Drayton Kittel

I have a question about a power supply for my first automation project here on the farm.

I'm building an automatic chicken door and I believe that I have all the components but I'm not sure on the power supply.

Let me explain the system.

Light sensor turns ON when the sun sets. Closes a relay.
DPDT relay starts the motor to close the coop door.
Door is closed and trips limit switch opening circuit

Sun Rises light sensor turns OFF and relay opens
DPDT relay switches polarity and reverses motor. Opening the coop door.
Door opens and trips limit switch which opens circuit.

The window motor is out of a Mercedes.

I need to source a power supply. There are plenty of 12 volt DC power supplies that I have from old printers and computers.

Learning about how to answer this question is more important to me than actually finding the answer.
That way next time I won't have to ask and can improve on my next project.

Questions:
Does the amp supply need to be exactly what the window requires?
If it is lower, will it just run slowly?

Well I'm new to all this. I have looked Into arduino before and it seemed much more complicated than what was explained.

I don't have any coding experience other than HTML in 1998. (Has anything changed? Lol ) my wife and have five chickens and I'm looking into aquaponics. This automation would really free is up. Especially since we have a three month old now.

My question to you guys with more experience is :
Where do I start ?

Do I need to Learn a programming language?
Which one?
How do I know which board to use?
Arduino?
Pico?
Raspberry?

Is there a web site where I can build and test projects and circuits before I start spending money on it? It may be cheap but new borns aren't.

I'm new to the Forums and this is my first Kickstarter too!

If I do the 15$ level do I get the levels below it as well?