Stepper motor - what assembly to grip and engage nylon cord?
Forums:
I've looked everywhere for a pre-built solution, and there just isn't one. (There's a stalled Indigogo campaign, search "MOVEZ").
Looking for recommendations on a suitable stepper motor and assembly to pull my standard window blinds cord. It's a standard cord loop, and I've no idea what sort of cogs or pulleys I should be looking for.
I'm pretty experienced with RasPis and tinkering with GPIO pins and badly soldered stripboard. The end result would probably end up being controlled by a Home-assistant instance or similar, through an Echo. I may even go to the extent of 3D printing a mounting box if all goes to plan, or at least use it as an excuse to buy a cheap printer.
Many thanks in advance for any help or recommendations you can contribute.
Ben
piborg
Thu, 11/30/2017 - 18:33
Permalink
A DC motor may work better
You might find that a DC motor with some limit switches will work better than a stepper motor for this kind of job. What you can do is get a reasonably high torqued motor and run it slowly to get a smooth pulling on the cord.
To grip the cord a 3D printed spindle may be the best way to go. With a slightly rough surface and a decent tension on the cord this should grip well enough to move the blinds reliably. You can then use the limit switches to prevent the blind being moved too far.
For motors I would suggest something like our 12V 100 RPM motor running at a nice low output should give a steady movement. You can drive these motors easily from a Raspberry Pi using our ThunderBorg controller :)