Do you know there are tons of these types of blinds commercially available?

?

 

Yeah

 

You will almost certainly have to make the coupler yourself. If you have a lathe it will be a simple job.

Les.

 

I was thinking of getting this coupler:

somehow removing the green shaded plastic cover from this end and then drilling holes on that sprocket in order to attach the coupling to the stepper shaft:

 

I'm not familiar with that type of shade. But some where there has to be some type of support to attach it to the wall. Where is that support in all of this? How do you propose to mount the motor? Would it be possible to get a photo of the drive end parts laid out as they are assembled, but separated ? To better see what you are working with. What is meant is like, shade roll - wall bracket - drive sprocket, or what ever the configuration is in real life.

 

I think its a pretty generic type of shade. There is a wall bracket that has a metal prong that hooks up to that center sprocket hole pointed to by the red arrow. That is how it mounts to the wall. Im not currently at home so I cant take it apart and photograph it but I posted some images on #16

https://www.google.hn/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwix_KSPl5jfAhXIslkKHWPzDeMQjRx6BAgBEAU&url=https://www.fixmyblinds.com/r-series-rollease-clutch-r16-53-for-1-1-2-tubes.html&psig=AOvVaw1mwtBFyCst5j-aCQMc540V&ust=1544631416418948

 

Here is the mechanism and images of some couplers I have that don't work because they are not fat enough

 

Ok I bought a flange coupler online but Ive come to realize that is not the way to go because I would have to cut open the closed off side of the mechanism (green shaded part on post #24) in order to connect the flange part to the sprocket itself and that would be messy.

I need to completely do away with the bead-chain-sprocket mechanism and just connect the stepper shaft to the white plastic fitting (that connects to the Al tube). Im not sure how to do that. Im guessing thats the piece I would have to make? Out of what, Aluminum? Im guessing aluminum since it would be light and could be more precisely machined to fit the 5mm shaft on one end of the stepper and the plastic insert on the side of the curtain.

Here is my design of the piece:

black left is the stepper
orange middle is the coupler i need to make
grey right is the plastic insert that slides into the al tube of the curtain

 

So what are you going to do for the part they call the 'clutch'? In the different ads selling them and showing the parts, it looks like a series of rubber "O" rings that are part of the sprocket drive. Or doesn't yours have a clutch?

 

Dunno what that is

I thought I just had to spin the al tube in one direction or the other.

 

Dunno what that is

I thought I just had to spin the al tube in one direction or the other.

Had a look at your pictures again. Post #27 upper left picture shows the clutch, the stack of black rings that look like "O" rings on the spindle coming from the chain sprocket.

Another thought is, where are you going to put the stepper controller? That won't be easy to hide from sight.

 

Hi SB,
I think that assembly is more of a brake than a clutch. I think it is to provide some friction so the blind does not unroll by itself due to tha weight of the blind material when it is partly unrolled. (If there was no friiction it would fully unroll.) That thought made me think with the stepper driving the blind directly it may need to be powered with some holding current to stop the blind unrolling by itself.
quique, Have you mesured the torque required to open to raise the blind from the fully down position and checked the the stepper you have is capable of providing that amount of torque ? The fact that you say the shaft on the stepper motor is only 5mm diameter makes me think that stepper motor will not be powerfull enough.

Les.

 

No I haven't matched th motor torque with the curtain one.

If I do indeed need the holding torque to keep it from unraveling then I'm in trouble cause I don't want to have current wasting.

I'm still working on the coupler piece to connect them.

 

One feature of a stepper motor is that it has a certain degree of holding torque when non-powered (off).
Max.

 

Hi SB,
I think that assembly is more of a brake than a clutch

Hi Les, clutch is what it was called by the makers/sellers but thought it was a brake also.

 

OK here is what it looks like:

The wooden board has 4 screws to the wall (which is chalkboard but 2 of the 4 screws are on a beam).

The stepper is mounted with 2 screws that go through the wood and into the wall.

I can report that it only works in one direction, downwards, due to gravity

I did previously try the motor with the coupler and curtain and it was indeed able to roll it up fine. I had someone hold one end of the blind up while I held the other end with the stepper and it worked.

 

Looks like you have rigid coupling, the best is a flexible type.
Max.

 

I had to use a rigid one because I had to make it out of nylon.

 

The commercial motors for roller shades go INSIDE the tube.

I built a curtain closer too in 1980 for balcony drapes. Replaced part of the rope with ladder chain. You need >2x opening of chain. A 24 VAC synchronous motor with a built in clutch. About 20 oz-in. The motor was spring loaded. If there was any serious jam, the chain would come off.

I machined two triangular pieces of aluminum and glued it to the curtain sliders. Then I machined two brackets that would adjust their distance from the wall to adjust the limit switch.

Put a man/auto switch on the wall with open/close and connected it to a simple timer.

Worked great.

Home would be hard: Roller shades nearly everywhere. Very little drapes and they are split level.

The one I'd like to motorize is a vertical blind. There is a bit too much force need to open them. Mechanism probably has to be replaced.
Besides that you have slat open/close and drape open/close and it's preferable to open the slats before moving the blind.

==

Check out Somfy.

==

Good numbers for drapes was a 40 oz-in motor and 20 RPM. and something like a 2.5-3" pulley. You can get ladder or bead chain pulleys.

2 springs on the end of the ladder chain didn't work well. You can also use the slide mechanism itself and put a limit switch there. As the motor pulls, the motor raises up when it reaches either side.

==

I'd like something like a single push button.

Push once if stopped - continue going in same direction unless at stop. If at stop, reverse direction. Stop at endpoint unless switch pressed.

Double-press if moving. Stop and change direction.

Single-press if moving - stop.

==

I'd like controls to be pulses. e.g. OPEN, CLOSE, STOP, REVERSE (possibly)
or have stop work correctly.

Goto x% would be ideal.

 

OK I just figured out why it didn't quite work, it's not properly aligned. I need to move either bracket