I am planning to create my own motorized blinds using 28BYJ-48 5V Dc stepper motors and there is enough literature for the software side but I am struggling with an important physical detail.
The blinds have a string attached which can be pulled down to turn it horizontal (90 degrees) or downwards (180 degrees).
Since the string is messy to work with, I am thinking of attaching a bead chain in a loop which can then be mounted on a drum or spool that goes on the stepper motor.
Since the movements are minimal and the motor is not required to lift the blinds weight, also thinking of buying a decent quality rechargeable battery and put it inside an aesthetic casing box (like the ones for Sonoff devices) and mount it on the wall and avoid doing any messy wiring for power.
But I am unable to find any spool or drum to mount the bead chain, I searched at Home Depot, Amazon, Ali Express, eBay and even Thingiverse for a 3D print design but came up with nothing.
I am not hung up on bead string either if there are other ways to connect the blind strings to stepper motor.
If anyone has done this project or has any familiarity then please provide some guidance.
Thanks!
I can help you with this as I made my own pulley based on a design on Thingiverse. I “motorised” some vertical blinds years ago, using an Arduino and steppers and which uses a chain to rotate the slats and a cord to open and close them. I used three LDRS set in tubes at different angles to detect the direction of the sun and rotate the slats accordingly but I digress…
The search term you need on Thingiverse is “Parametric ball pulley”. That should bring up a few designs. If you don’t have any joy with that, I can supply you with an Open scad file that you can use to generate an STL for whatever dimensions you want. If you don’t have OpenScad, I can let you have an STL for the one that I made. If you don’t have a 3D printer, I can make you a pulley for nothing but you’d need to pay the postage (I’m based in the UK). Let me know.
@deckingman thanks for the term "Parametric ball pulley”, the results on Thingiverse are awesome and should solve the problem!! Also appreciate your offer to print it for me, let me try my hands on 3D printing and may need to come back to it!
Also found a great page where there is a good collection of accesories for 28BHY48 stepper motor
