Stepper support request; for curtain automation <€30

[Domosapiens]

Hello,
Impressed by reading about ESP Easy, great job done!

My request in short: please consider support for the universal A4988 stepper motor driver module:
- select 1 out of 5 step modes
- select direction
- give it a number of pulses

Background:
I'm currently in the conceptual design phase of automation of a set of wave curtains (4 and 2.5meter).

I have selected the Haydon AMETEK-LC1574-W linear stepper motor (15mm x 40mm).
http://www.haydonkerk.com/?TabId=86
By adapting the white cover, it can be used as a rotating stepper motor (remove the cover, saw a few mm off, and the 2mm axis can rotate freely)

Stepper.JPG (27.11 KiB) Viewed 9736 times

The 2mm axis is hidden under the black cover.
Cost €4.53, bought here(only the 4V (!) version is available):
https://nl.aliexpress.com/item/Mini-lin ... =100007153

Strong enough (7N) and accurate enough for closing a 4meter curtain with approximately 2500 steps in around 25seconds.
The stepper motor mounting on DIN rail will be done with a M12 nylon nut on the white cover.


I have selected the A4988 stepper motor driver module.
https://www.pololu.com/product/1182

A4988 stepper driver.JPG (24.51 KiB) Viewed 9736 times

Cost €0.73, bought here:
https://nl.aliexpress.com/item/5pcs-lot ... Title=true

- the A4988 has a translator for step modes: one pulse,one step.
- the Vreff adjustment enables Voltage/Current limitation (needed for the 4V/0.2A Haydon stepper).
Simple control:
- select 1 out of 5 step modes (selector inputs pin MS1, MS2, and MS3)
- select direction (DIR pin)
- give it a number of pulses (STEP pin)


A nylon fishing line will be winded/unwind-ed (at the same time) on two spools on the stepper axis:
https://nl.aliexpress.com/item/10x-Dura ... Title=true

Spool.JPG (22.21 KiB) Viewed 9736 times

The 2mm axis goes via a shaft coupler to 5mm to hold the 2 spools.
https://nl.aliexpress.com/item/5pcs-lot ... 28631.html

The fishing line is guided by Nylon U groove ball bearings:

Nylon wheel.JPG (16.53 KiB) Viewed 9736 times

https://nl.aliexpress.com/item/2pcs-Nyl ... Title=true

Additional needs:
- 0.3 mm breaded fishing line
- 50cm DIN rail
- project box mounted on DIN rail
- ESP board
- 2x power supply (TSP-05 and TSP-12)
- plugs (XS8 2Pin and XS8 4pin) ( https://nl.aliexpress.com/store/1724883 ... t=xs8+plug )
Total cost < €30 per curtain

For another 5 small windows of 80cm I have planned to use a 2GT belt with 2GT pulleys
https://nl.aliexpress.com/store/group/2 ... 78143.html

Belt.JPG (16.14 KiB) Viewed 9736 times

I hope this will inspire others
and ... to get support for the A4988 stepper driver included in ESP Easy.

Thanks
Domosapiens

[majklovec]

viewtopic.php?f=6&t=2356

[Domosapiens]

Hello majklovec,
Yep, I had seen that one (search on: stepper).

But that one does not look ESP Easy

To me that is EPS Complex.
The last time I compiled code was 40 years ago.
Hope to enthuse the ESP Easy team to include the universal A4988 stepper motor driver module in the binary.

Would be a nice Christmas presence.
Domosapiens

[majklovec]

It's super easy go for it and compile it by yourself: http://www.letscontrolit.com/wiki/index ... are_Upload

[Jazzle]

So Domosapiens, did you eventually automate your curtains?
I am looking for a cheap way to automate tilting of my Venetian blinds (jaloezieën) and your setup looks like a great option!

[Domosapiens]

Hello Jazzle,
Made some prototype progress, but not that fast.
Every design change takes some 20-30 day of waiting for the china post...

The Haydon AMETEK-LC1574-W linear stepper motor modified to rotational motor has no torque enough (I could have known!)

So I moved over to his one:
https://www.ebay.com/itm/1PCS-Used-27mm ... 282f328fa0
(after using the 1:36 ratio version that was too slow)

Winding & unwinding on the same axis for a curtain of 5meter was no success.
Too much circumference difference on the 2 spools.
I tried to equalize it by a spring cord, to give tension on the motor frame but in the middle of the closing process the difference was 15 cm ... too much for an elegant mechanical design.

So I moved over to 2 motors: one for winding and the other one for unwinding at the same time and slower/faster then the winding motor to compensate for the dynamic circumference difference on the spool.
For that I had to drive two steppers at the same time controlled by two Tasks (for GPIO reasons).
I developed the algorithm: leave steps out or add additional steps for the unwinding motor.
That became unreliable by the stretch ability of the fish line and dual Task synchronization.

Using a belt is not an option for aesthetic reasons.

Then I introduced two electromagnetic clutches.
https://nl.aliexpress.com/item/Electrom ... 2399.html
The winding clutch is activated (12V is enough) while the unwinding clutch is slipping on low voltage (around 5V).
This means that the winding motor needs more torque: not only for the curtain but also for unwinding.
But only one stepper to control at the same time!
This appears as the most practical solution.
I have made the mechanical prototype controlled by a breadboard and ESPEasy_v2.0.0-dev7 plus stepper code to control 2 motors

Funny to see how design decisions are bouncing between:
mechanical - electrical - software - technology complexity
If you make one aspect simple it has to be compensated by the other aspects.

The project is ready for implementation, but currently there are other priorities and waiting for a stable EspEasy version.
The 5 smaller 80cm windows will get a belt (hidden behind the rail)

And for my 2 Roman blinds I use these ...:
https://nl.aliexpress.com/item/Free-shi ... itle=true
Expensive ... but simple and operational in a few hours.