Arduino Uno, and Motor Shield to move pet flap; overkill / feasible?

The situation:
We have a cat on medications and another cat that consumes everything from medicated food to strings to nerf bullets. Currently, have a side table boxed in with a microchip controlled pet flap which only allows access to the cat requiring medication. Trying to modify the flap to move up and down (both directions - in and out) without dragging on the cat's back and also slamming shut.

The plan:
Use cable or rope or string (etc.) and pulleys to raise and lower the flap with motors. Ultimately, when the cat pushes on the flap, it will raise, in the direction she's pushing, from it's vertical position to a horizontal position (90 degrees); remain in that position for a specified amount of time, then lower to the original position until another push on the flap starts the process again.

Questions / concerns:
Is this feasible?
Thought of using the Arduino Uno with Motor Shield, is this overkill?
Recommended motors?

I've put together a couple different prototypes with cardboard, string and pulleys; now I'm stuck on the capabilities of the motors and programming. After scouring the internet and finding bits and pieces of the dream, I'm unsure if putting the pieces all together is going to create havoc. Any questions, thoughts, ideas, direction are welcomed and appreciated.

There are lots of similar projects on the forum (surprisingly many chicken coop doors), so google "arduino pet door" or "arduino chicken coop" for ideas.

seeing that overkill is past tense for you, why dont you make a cat necklace that in turn opens the door to slide to the side instead of going up so then it doesnt matter what side the cat comes in from the door will automaticaly open to the side everytime like a sliding glass door, you will only need one stepper motor going in both directions for this and you can be sure that only the cat with the collar can enter, it should be fairly easy to write the code for this.

We have a commercial one of these to stop neighbors cats getting in. Cat has a collar with RFID tag, as she approaches the cat flap, it unlocks, cat pushes it open.

The cat flap can always open outwards.

Side note: Our cats learnt how to pull the cat flap open eventually which meant we didn't need to use the collars anymore.

jnj30:
Thought of using the Arduino Uno with Motor Shield, is this overkill?
Recommended motors?

I suspect the opening and closing could be done with a servo and that would make the mechanics, the electrics and the programming much easier.

...R

jremington:
There are lots of similar projects on the forum (surprisingly many chicken coop doors), so google "arduino pet door" or "arduino chicken coop" for ideas.

Thanks! I'll do that.

Frostedfocus:
seeing that overkill is past tense for you, why dont you make a cat necklace that in turn opens the door to slide to the side instead of going up so then it doesnt matter what side the cat comes in from the door will automaticaly open to the side everytime like a sliding glass door, you will only need one stepper motor going in both directions for this and you can be sure that only the cat with the collar can enter, it should be fairly easy to write the code for this.

I like this idea. I'm thinking I could use their implanted microchip instead of a collar (she's become a Houdini cat with collars). Better to go with a stepper over a DC or servo?

jnj30:
I like this idea. I'm thinking I could use their implanted microchip instead of a collar (she's become a Houdini cat with collars). Better to go with a stepper over a DC or servo?

i stepper motor would be more expensive, if you want to save money buy a good standard servo and remove the direction blocking pin and then the servo will be able to turn 360 degrees, if you use a servo then you dont need the motor controller and all the gearing is already built in, it will save you money and also alot of time on the final design and build.

I hope this helps

Just found this, check it out... http://www.instructables.com/id/IoT-Outdoor-Pet-Door/