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school project - Automatic Chicken coop door

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schapman

New Member
Hello All

I am needing some help on a project for my daughter's school. We are building a new chicken coop and wanted to install an automatic door on it. I have some material available that I thought would work in this project.

12v battery
12v timer - I can set to go off upto 4 times a day and can limit the run time from 1 to 60 sec. (deer feeder timer). It has 2 wires going to a battery and 2 going to the motor.
I was thinking I would use a window regulator and frame out of an automobile window.

Im not sure how to wire it to reverse the motor to go up and then down. I want to keep it as simple as possible and reliable is a must.

Thanks for your time.

Steve
 

crutschow

Well-Known Member
Most Helpful Member
I believe you just reverse the voltage polarity to the motor to reverse its direction, which can be done with a DPDT relay. The difficult part is generating the logic to control the motor and relay. If someone can program a microprocessor, that would be the simplest way.

You probably also need limit switches to stop the motor at each end of its motion.
 

schapman

New Member
the frame out of the auto operates like a sissor lift it can only go so far. the timer i can set to run at second intervals so i can limit the motion as well by the run time i set it to possibly 3-4 seconds. can it be done with just the DPDT relay?
 

crutschow

Well-Known Member
Most Helpful Member
the frame out of the auto operates like a sissor lift it can only go so far. the timer i can set to run at second intervals so i can limit the motion as well by the run time i set it to possibly 3-4 seconds. can it be done with just the DPDT relay?
It may only go so far but I don't think you can leave power applied without burning out the motor.

You can use the DPDT relay to reverse the motor but what would you use to control the relay so that it reverses at the proper time? That requires some logic and memory circuits. You have to write down the sequence of events you need to control, and then generate a method to execute that sequence.
 

schapman

New Member
ok the timer goes off at 7am and runs for 3 sec. sending power to the motor for 3 sec and turns off.
then at 6pm it will go off again for 3 sec sending power to the motor.
at the 6pm setting i need it to reverse the polarity
 

crutschow

Well-Known Member
Most Helpful Member
ok the timer goes off at 7am and runs for 3 sec. sending power to the motor for 3 sec and turns off.
then at 6pm it will go off again for 3 sec sending power to the motor.
at the 6pm setting i need it to reverse the polarity
The problem is, how can you differentiate between the morning timer pulse and the evening timer pulse?

You may need another timer to do that. The second timer could control the reverse relay.
 

SABorn

New Member
Here is a circuit that is untested but should work.

The limit switched are fitted to the top and bottom of the door travel, and will need to be micro switches to ensure positive switching.

The timer will need to come on and switch off before the door makes full travel (pulse only)

It will be a bugger of a circuit to wire up, but should save the need for a logic ic.

Pete.
 

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