FWIW.. Some cheap ($12.95) 12V geared motors, limit switches,etc.. here..
http://www.mpja.com/DC-Motors/products/100/

I'm going to be doing the same project in a month or so once we move into our new house..
Yes I can just crank the handle.. But having it on the remote with the fireplace, dimming lights,etc... just adds the "coolness" factor and really sets the mood... bow chica bow wow..

 

My first and only curtain controller was done some 35 years ago with a surplus 24 VAC synchronous motor. It did have a built in clutch. It was similar to the smaller varieties here: http://www.hurst-motors.com/permanentmagnetacsynchronous.html#55mm Something like 20 RPM, 40 Oz-in I think was what I measured to pull the string. The purpose was to automate my GF's balcony curtains. So, the numbers the OP/TS got don't seem too out of line.

i had access to a machine shop, so I fabricated some adjustable L-brackets with a microswitch and an aluminum wedge glued to the things that the rope pulls so outward movement, meant the drapes stopped closer together for the center,

The drive was a simple open frame gizmo that had the motor slide using Nylon step-collars in a slot, A portion of the rope was replaced with ladder chain slightly greater than 2x the opening. The motor was spring loaded, so you had tension on the rope, If anything bad happened, the chain fell off. Manual operation, in an emergency was just take the chain off.

I did not know of bead chain and bead chain drive gears at the time.

A small box with auto/manual and open/off/close was added and a simple timer provided the auto operation.

Synchronous motors stop instantaneously. Three wires. A common and a capacitor between the other two. Power is applied to common and one end of the capacitor depending on direction.

I've done some motion control stuff with and adjustable slip clutch and a misalignment shaft coupler.

There's some reference designs for car window systems on the net which are more complicated. They do something different, the very first time they are used. This http://www.nxp.com/assets/documents/data/en/reference-manuals/DRM160.pdf design is fairly complex/

Aside: One other thing I did for her, was to create a thermostat set-back controller. This was a resistor mounted in a bakelite box with a screen on top and a dimmer control attached to a timer. So, it was mounted under the thermostat and "tricked it.

 

So some 35 years ago, micros and all of the fancy stuff really didn't exist. Motors were hard to come by. I did get something like this https://www.servocity.com/25-rpm-offset-gear-motor back then to play with. I really wanted some kind of encoder and it was reasonable enough to be used flat against the wall. I tried to do something with a counter IC, but was unsuccessfull.

There were thoughts about trying to make a tap/tap sort of interface. e,g, tap once and at limit it would go in the opposite direction. If moving a tap would stop it. Another tap would continue in the same direction and a double tap would stop and reverse direction.

Thoughts also existed to use current limit as a HARD type of limit and counting as the mode of choice.

With some sort of rising/falling edge trigger mechanism for open/close. Now you have the choice of IR, bluetooth and WFI

FWIW: I do have a vertical blind that needs a new string. The trick is to fuse the old and new cords together with a match and pull it through, It's also a very large blind. I repaired one of the end mechanisms with new parts about a year ago and added a much needed center stop using a reamed Delrin collar. The current issue is that the string weight hangs up and it appears to be the cord, but could be the weight.

Most of the house is "roller shade based" with translucent decorative curtains. Automating a vertical blind would clearly take some effort. Some windows like the bathroom and doors have shutters with adjustable louvers.

 

Finally, I did it! Check out this YT video. Parts are listed under descriptions.

Alternatively, you can use these parts

 

Hey, good job man! You obvious had more resolve for this project than I could muster. LoL.

 

Good job. Looks great and well executed.

 

Love doing with my 15 year old son !!