Hello everyone!
I am planning to Automate the curtains i have at my place. I've searched the forums and found many useful information to start with. I'll be using HM10 to control it wireless.
The curtains I have are of 2 types.
- Rollers with ball/beaded chain loop. Pull one side to raise and the other to lower.
- Sliders with a thread loop. This curtain has 2 parts. When one side of the thread is pulled the curtain moves away from the center and the other side closes the curtain.
I have decided to use a worm geared reduction motor to turn the pulley of the beaded chain using a sprocket i got from an old Roller Curtain. I will be searching for a non worm geared motor as worm gear will stop the curtain from operating manually. Any suggestions on this will be helpful too..
The main problem I have is what pulley or sprocket can i use to push and pull the curtain's thread?
I found GT2 timing belt pulleys with 6mm Inner diameter(motor's shaft is 6mm). But what can I do to grip the thread on the pulley ?
I tried winding it thrice and the turning the motor, but the tread winded shifts slowly to the other end.
What are the possible ways to overcome this.
Any help or ideas on this will be of great help. And i am trying to fix this as a device enclosed in case,so changing the curtain mechanism isn't what I am looking for..
The motor has enough torque to pull the curtains..
Thank You for reading and sorry if i have missed any info needed.
If, by "timing belt pulley" you mean a pulley for a toothed belt then I suspect a pulley without the grooves for the toothed-belt would be better. A pulley with a V shaped channel will get a better grip as long as the "thread" is wide enough not to drop right to the bottom of the V.
Another idea is to have a spring-loaded roller to squeeze the "thread" against the driving pulley - but that would not work with a toothed-belt pulley. This has the advantage that the entire "thread" does not need to be taught.
A larger diameter pulley will get a better grip (more surface in contact with the "thread" but will also require more torque from the motor.
What diameter is the stuff you refer to as "thread" ?
...R
Hi!
You have an interesting project. I have been thinking about something like that myself. My jalucias are turned by a stick rotated cc or ccw.
One question is to find motors producing enough tork.
The other question is to secure endstops in order to protect the jalucia from damages.
Positioning the jalucia in an analog manner or just go from completely open to totaly closed is another question.
The mechanical interface is of course also a question. We need to be like Mc Gyver....
Hi again!
Youe write about " Rollers with ball/beaded chain loop.". Not having a picture to look at I guess and wonder if they come from IKEA? I recently bought such chains and their pully at IKEA. They din't cost much.
A long shot….
@Railroader
I am assuming Jalucia means a curtain because I don't know what it is..
I found motors with 10kg/cm of torque. That is enough to do the job in my project 
Yeah, about endstops i was thinking of some sort of signal to the arduino when it reaches a position. What are your ideas about endstops ?
About the ball chain pulleys, its not very expensive anyways and its only for a single curtain.
Hi Robin2
I will search for a V pulley and see if i can find a good enough one. Because when the motor rotates one end will be leaving the pulley and the other will be winding on it. So wont the V belt pulley be a problem as the entering side will be winding on the thread which is already and when that leaves the thread wont be tight enough to grip on the pulley? (just a doubt)
The diameter of the thread should be between 2mm to 3mm..
Robin2:
Another idea is to have a spring-loaded roller to squeeze the "thread" against the driving pulley - but that would not work with a toothed-belt pulley. This has the advantage that the entire "thread" does not need to be taught.
Sorry, I didn't understand the above quoted one
And yeah, as some curtains are heavier and considering the torque of a DC motor in a budget I'll have to limit myself to a not very big pulley.
Jalusia… Horisontal blades that can be moved from horisontal to vertical position. Never mind, moving from open to Close by a rotating stick/handle....
In the case of DC motors end stops could preferably stop the motor using a micro switch and a diode. That allows for an easy motion in the other direction. The motor You suggest irs really powerful.
Running such a torc full motor and rely only on digital logic feels like not top safety. Cut the motor power off the hard way and inform the logic that the end position is reached. I have seen the "logic" version crashing mechanícs and/or computers.
All mechanical interfaces are challengies. That's the charm....
3rroR431:
I will search for a V pulley and see if i can find a good enough one. Because when the motor rotates one end will be leaving the pulley and the other will be winding on it. So wont the V belt pulley be a problem as the entering side will be winding on the thread which is already and when that leaves the thread wont be tight enough to grip on the pulley? (just a doubt)
I was not thinking of having multiple turns of cord on the pulley. In my experience that causes tangles
Sorry, I didn't understand the above quoted one
Something like this
...R