DIY Smart Blinds v3.1 – How To with NEMA 14

This project aims to upgrade the popular DIY Smart Blinds v1.1 with a Nema stepper motor in order to increase the torque for moving roller blinds. For this project, my biggest concern is the size of the Nema motors. The aim of this version is to keep the form factor of the device as small as possible, give it as much pulling power as possible and allow for a standard 12v power supply. I have estimated that the total cost of this project is between $40 AUD – $60 AUD depending on where you source your components. Below is a short teaser of the project.

The Motor

For this project I will use the NEMA 14 Stepper motor. It is small enough at 35mm x 35mm x 26mm. Its 12v and has the torque of 14N.cm (20oz.in.) compared to the 28BYJ-48 motor used in the previous design which is approx. 2.9N.cm. This should make this device almost 5x stronger (based on estimated values from manufacturers specs, results may vary).

Nema 14 Motor

The Driver

To control the stepper motor, the design should use the A4988 motor driver. It is a noisy driver but it is inexpensive and capable of controlling this Nema 14 motor.

A4988 Stepper Motor Driver

The Processor

I have used the Node MCU ESP8266 processor for many of my projects. It can be easily programmed using the Arduino IDE, its small and it has WiFi built in. Not to mention great community support. Hence for this project I will use it again.

The second option is the NodeMCU ESP8266 WeMos D1. This processor has a smaller form factor and could also be a good choice.

Considerations

  • NEMA 14 or NEMA 17 stepper motors get hot when they run, a 3D printed PLA enclosure may not be able to sustain the heat buildup during operation. Testing shows that typical operation only lasts a 5-10sec then pause. Hopefully this should not raise the temperature too high.
  • For this design I have chose the NEMA 14 motor dues to its size. However to get an even more powerful motor and scaling this design should not be too much effort.
  • NodeMCU is a better choice because it has VCC in pins. The WeMos D1 needs to be powered through the micro USB port.
  • To power the circuit from one 12v power supply, a 12v to 5v Buck converter will be required. There are various but converters on the market. Make sure you choose one that can handle a current of 1-2A as a stepper motor can be drain quite a bit of current per phase.
12v to 5v Buck Converter
Test platform

Schematic Diagram

What you will need

  • ​nodeMCU Board
  • A4988 Motor Driver
  • 12v to 5v Buck Converter
  • Nema14 Stepper Motor
  • 5.5mm x 2.5mm DC Power Port
  • (8x) 2.5mm x 6mm Button Head Screws (for the lids)
  • (2x) 2.5mm x 6mm Self Tapping Screws (for nodeMCU mounting)
  • (4x) M3 x 6mm Countersunk Crews (for the motor mount)
  • STL Files (link below)
  • Software (links below)

Software

DescriptionLink
Arduino Sketch (this may evolve over time)GitHub link
Homebridge plugin / Homekit GitHub link
Samsung SmartThings – device handlerGitHub link

The Design Shape

What form factor should the DIY SmartBlinds v3 have?

  • Rectangular Shape similar to v2 (54%, 13 Votes)
  • L-Shape similar to v1 (46%, 11 Votes)

Total Voters: 24

Loading ... Loading ...

Thank you everyone that participated in the survey. As requested, the design is rectangular. I designed it with a chain guard all inclosed. Checkout the design renders and some first assembly photos below.

DIY SmartBlinds v3 first preview

3D Printing

TIP: When printing the main body, print it with a brim. 8mm should be sufficient. Due to the walls on the main body being only 2.5mm thick, I found that when I printed it without the brim the model would get unstuck halfway through and the print was destroyed.

Brim around the Main Body for a sturdy print
Printed on: Prusa i3 MK3
Filament used: 3D Fillies PLA+ Marble
Print mode: Built plate brim for the body only/No supports
Print quality: 0.2mm
Print time: 5-6hrs

Assembly

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74 Comments

  1. I have been messing with your blinds version 1.0 for a bit (in between other projects) and finally got it all working today. However, the torque on the 28BYJ motors is just not enough power to operate my roller blinds. I even tried trimming down the blinds so they were not as tight and rolled as easily as I think possible.

    I am very interested in the v3.0 project. I’d like to get started but I am pretty new with Arduino – is there a specific driver board I would use with the Nema 14?

    1. Hi Bert, I think the most cost effective driver will be the A4988 based one. It’s small enough and together with the NODE MCU that should make the setup compact. I don’t like that the Nema 14 has such a long shaft. It will stick out unless the enclosure is a bit thicker. Speaking of enclosures, should the enclosure be similar to the design in V1 or more like V2?

  2. I have just got my drapes sort of working.
    Mine are from this instructable……https://www.instructables.com/id/Alexa-Curtain-Control-System-3D-Printable-and-Low-/
    Drape size 1600 dropx1500 wide & 1600 drop x 2000wide.
    Alexa can operate them 1×1 but not both together in a routine.
    my case is 140x80x50 using 47x42x42 stepper motor which i had at the time.
    At the moment they are 12v battery operated which is why the case is so big.
    Love to see what you get going with the samsung smart things.

    1. Hi Neil, I already have the SmartThings Device Handler built for the DIY SmartBlinds v1 & v2 from my website, You should be able to find the link here: DIY SmartBlinds v1 + SmartThings Device Handler. I am now working on DIY SmartBlinds v3 which will incorporate a Nema14 (35x35x26mm) stepper that is 5x more powerful than the original design. Nema17 would be 10x but its bulky. I want to try and keep this unit as small as possible. Unfortunately I hit set back, I fried 3 of my WiFi NodeMCU and Wemos D1 boards thinking they can handle a 12v input – wrong! I will need to order a few more and use a voltage regulator to drop the 12v to 5v to power the NodeMCU or WemosD1.

  3. Hi peter, been working with the Nema version of the smart blinds, about the hardware, yes a buck converter is needed to step down to 5v, i would go with the buck converter instead of a mosfet or similar, it runs safer and cooler. The issue I had is the software I tried to convert the code to the AccelStepper library with no luck, I believe AccelStepper library is one of the best out there to drive Nema steppers. Let me know if you want me to beta test.

    1. I have a soft tested sketch for the NodeMCU that uses the AccelStepper library. I will post on Github later and a link in the post. you are welcome to test it on your hardware.

  4. Perfect, sure I will test it and get back to you if I find any issue.

  5. I have uploaded the first port of the Arduino sketch if anyone wants to give it a try. Please not the wiring in the schematic diagram. Also if you are not familiar with the A4988 driver, please read up about adjusting it for your specific NEMA motor. You will need to set the current limit on the A4988 to suit your motor for optimal performance.

  6. Hello.
    I got this error
    [Config] Homebridge Config UI X v4.23.2 is listening on :: port 8581
    [7/11/2020, 7:35:37 PM] [Office Blinds] getTargetPosition : 100
    [7/11/2020, 7:35:37 PM] [Office Blinds] HTTP bad response (http://192.168.1.100/api/status): connect ECONNREFUSED 192.168.1.100:80

    I have no any connection in my “HOME” IOS APP

    Please help me to understand what a mistake

    1. This could be related to your device not connecting to your WiFi network correctly. Have you searched for issues relating to WiFiManager? perhaps try a different version of the library? Try reseting your WiFi Settings with WiFiManager and try reconnecting the NodeMCU back to your WiFI network. Hope these help.

  7. Thank you for your answer.
    I did many attempts. I think the problem with library, because I even change router, did reset settings and still have nothing.
    I have node js version 12.x.x
    But required is 7.6

  8. How should I save my wifi settings in wifiManager?
    I can’t see any settings in the .ino file

    1. Here are the library versions I used for this project if this helps:
      ArduinoJson 5.13.2
      WiFiManager 0.15.0
      ESP_EEPROM 2.0.0

  9. All libraries are same.
    As I see on this page https://github.com/tzapu/WiFiManager/blob/master/README.md
    I need to connect (default ip 192.168.4.1) to set up wifi settings

    But I can’t open the page 192.168.4.1, 192.168.4.1:8080, http://192.168.4.1:8080

    1. When I connect my NodeMCU devices gin te WiFiManager library, I use an iPhone to connect to the WiFi that the device creates. Then I add my home wifi settings, said and pass and connect. Once it connects, I find it on my home router in the DHCP list. Then I can connect to it directly on port 80. That’s it. I would usually setup a DHCP reservation so that the device does not change its IP when I use it with SmartThings or HomeBridge.

  10. wifi said: DIY-SmartBlinds
    but I can’t see it im my wifi list on my iPhone

    1. Perhaps you need to start from scratch. Find the most basic Arduino sketch using the WiFiManager library and see if you can get your NodeMCU to connect.

  11. I flash standart example but I have nothing. May be hardware problem?

    1. Could be. I have a NodeMCU that overheats, yet if I replace the circuit with another it works cold.

  12. Just for last attempt. How can I put ssid and pass on the code directly?

    1. I have never tried that. You may need to refer to forums related to the WiFiManager library on GitHub.

  13. Also please check the dc converter polarity With vmot and gnd lines. Something wrong

  14. Hi there, I’ve just got this working. Thanks for the great instructions. I’ve made my own case for now but look forward to yours when it’s ready. Everything worked the first time around. Just need to put everything together as it’s on the breadboard at the moment.

    1. Oh yeah, as Mikahil pointed out, the polarity specified for the stepper VMOT and GND in your wiring schematic seems the wrong way around.

    2. Thank you for pointing this out i will update and repost.

    3. Hi, great design!

      Two questions:

      Can the NodeMCU ESP8266 be powered of usb at 5V?

      Does it work with https://www.home-assistant.io/ ?

      Best regards

    4. Hi Bo, not unless you can find a motor driver that can power the motor with 5v. I believe such exist but are expensive compared to the A4988. The A4988 requires a minimum of 8v-35v for the motor but the circuit can be powered by 3.3v-5v. Best to check the specs. You will also have to make sure that the stepper motor matches the voltage and power requirements.

      Perhaps someone else could comment on this?

      As for the home-assistant integration, I am sure you could write a plugin or someone in the community could assist. I have only provided the plugins for SmartThings and Homebridge -> Apple HomeKit.

  15. Error processing received information: undefined
    what error is that?

  16. Can you please specify which motor model should I buy? I see a few different NEMA 14 constructions. Did you use JK35HY26-0284 ?

    1. I used Nema 14, 14HS10-0404S, 0.4A per phase, Bipolar. I think you can use anyone but you should take care and adjust the voltage limiter on the motor driver.

    2. Thanks for your reply!
      Would there be a space for 35x35x28 mm instead of 35x35x26 mm motor? I’m considering buying JK35HY28-0504 over JK35HY26-0284 and then I probably wouldn’t need to adjust the voltage limiter at all.

      Additional question:
      Can you tell when would your model will be available? 🙂 I’m not in hurry, just asking out of curiosity.

    3. The gap between the back of the motor and the screw mounts is tight. The design has only a 1mm gap behind the motor. Main body with Nema14 Top View

    4. Hi Filip, I just updated the design to accomodate a Nema14 35x35x29mm MAX. You should now be able to first the Nema14’s you wanted to get.

    5. Oh, and I noticed that your model will probably suit only 3 mm string beads. Would it be possible to create something for 5 mm beads in the future?
      I have large roman blinds and unfortunately all of them use those thick beads…

    6. Yes I can try to design a bigger cog and add it to the bundle. Can you tell me what the gap between the 5mm beads is?

    7. Thanks, that would be perfect! My beads are actually around 4.60 mm in diameter and the gap is 1.70 mm.

      Regarding the gap behind motor – that’s fine. I will just order the smaller one and adjust the voltage then.

      I’m also considering “daisy-chaining” multiple units (motors with their controllers, each in separate case) with one ESP module controlling them all. I have wide windows with e.g. 3 separate blinds.
      That way I would reduce the cost (less ESPs used), WiFi interference and hopefully some hassle. Do you think that would be a good idea?

    8. That’s an interesting idea. However with one ESP you will need to run at least a 5 core wire between the devices. Maybe you could use a CAT5 cable for this I think they are rated for about 2A.

    9. Hi Filip, I made a cog that may work with your 5mm ball chain. Give this STL a go. DIY SmartBlinds v3 – Cog 5mm

    10. I have some YTDY 5×0.5 mm (0.196 mm2) left so I may try that. For me this cable worked well at a short distance of 5 meters. I’m already powering Sonoff camera (12V, 1A) that way.

      For this cable size (0.5 mm diameter) and length of 5 meters – at 2A current flow voltage drop could be around 0.872V. Anyways I will investigate that idea when I have all the components needed 🙂

  17. Hi Peter, I really want to get this working with Alexa but I’m having trouble getting it to work. Can you provide some instructions on how to link it to Alexa please. I tried the SmartThings stuff but I’m stuck. Thank you.

    1. Can you describe what exactly are you having a problem with?

    2. I’ve created a SmartThings account, I’ve added the code for the Device Handler and created a Device. I’m just not sure what I do now. Do I need a SmartThings hub for this to work?

    3. Hi Ali, yes if you want to automate the blinds, I.e. open them or close them at certain times, then you will need a hub. If you are integrating the DIY SmartBlinds with smartthings then you will need the SmartThings Hub. You can also integrate the SmartBlinds with Apple HomeKit but you will require a Homebridge (it’s another kind of hub that works with HomeKit) Once you have the SmartThings hub, you can also connect Alexa to it and operate the blinds vie voice. However, please be aware that as of this writing, Alexa can only respond to “switch the blinds on” or “switch the blinds off” to open or close them. Amazon is working on this and looks like a solution is coming soon.

      Personally I don’t bother with voice control of the blinds, mine just open at sunrise and close at sunset.

    4. Thanks for your reply!
      Would there be a space for 35x35x28 mm instead of 35x35x26 mm motor? I’m considering buying JK35HY28-0504 over JK35HY26-0284 and then I probably wouldn’t need to adjust the voltage limiter at all.

      Additional question:
      Can you tell when would your model will be available? 🙂 I’m not in hurry, just asking out of curiosity.

    5. Hi Filip, I am testing the 3D design now. I hope to make the STL files available this weekend for a small gratuity 😉

    6. Thanks Peter, that makes sense. I’ve actually managed to get it working with Alexa by using the home bridge plugin which allows control through Siri on my phone. I then installed the Alexa-Homebridge plugin which made it controllable through my Alexa devices. I can now say “open the blinds” and “close the blonds” through Alexa and it works great. Took a few steps to get there but is perfectly how I wanted it now. Thanks

    7. That’s great. How responsive are the blinds when using Alexa through homebridge?

  18. Hello. If I want to use tmc2208 drivers
    What wiring diagram should be?

    #define dirPIN D5
    #define stepPIN D6
    #define sleepPIN D7
    #define hotPIN D8

    Thank you.

    1. Hi Mikhail, I am not using D8, I will remove it from the code when cleaning up. As for the TMC2208 driver module, please refer to this pinout TMC2208 PINOUT From the diagram STEP -> D6, DIR -> D5, ENABLE -> D7.

  19. Hi Peter, This is a really awesome project and it’s great that it makes use of the NEMA as some of my blinds are quite heavy for the smaller steppers. I had a go at designing this in Fusion 360 while waiting for your design just for fun (not as good as yours, but I got fairly close), and it got me thinking if it would be possible to add up/down/stop buttons and some sort of interrupt to the code to manually open/close the blinds with these? I have 2 Zigbee IKEA blinds connected to my Smartthings hub at the moment and every now and then find I need to manually use the buttons if the WiFi has gone down. I’m worried opening by hand when the device is connected to the chain might cause strain and break it eventually. Thoughts?
    Otherwise, any chance you will be making the Fusion360 file available too, as I was thinking of trying to add a hole for the buttons myself, and perhaps a few slits for ventilation. (The nodeMCU I use to control my garage currently gets a tad hot sometimes in its 3D printed box, and the Arduino Uno I had before that kept freezing in summer).

    Cheers!

    1. Hi Dale, Thank you for your comments. Unfortunately I will not be releasing the source Fusion files. The STL files should be available this weekend.

      I stayed away from manual controls as this project was all about automation. Having said that, the thing about the Nema motors is that if you are not running current through them, they spin fairly easily. So you can safely use the chain to open the blinds.

      For roller blinds, I am not sure that the Nema14 will be strong enough. I think you would need the next size up Nema17 at twice the torque.

  20. The blinds are very responsive, if I say “Alexa, close the living room blinds”, they start closing within a second or two. I’m just soldering the components together now so once I’m done I’ll create a video and post the link here so you can see. By the way, do you happen to have an STL file for the bead chain pulley as that’s the only thing I need now. I was going to find one online but if you have one that would be great. Thanks.

  21. Hello. When using TMC2208 should I change something in ino scetch?
    Thank you

    1. I don’t have any experience with the TMC2208 driver but from the looks of things there is nothing you need to change. Have you looked up any guides on how to use it with Arduino and a Nema motor?

  22. Hi guys. It is a very interesting project. But A4988 driver is very loud. I trying to update it with TMC2208. It should make blinds noiseless. But Now I can’t understand what is wrong. Can’t start my driver for now.
    I connect d5 -> step d6-> dir
    d7 -> Enable. Also motor pins were changed. But still nothing.
    Does somebody know the reason?
    Thanks

  23. Hello. Any one who want to use TMC2208 driver with this excellent project should change
    digitalWrite(sleepPIN,HIGH); To LOW.
    And
    digitalWrite(sleepPIN,LOW); to HIGH
    in the sketch. Because tmc2208 use reversing protocol on EN pin.

    1. Thank you for posting. I am keen to try this driver myself due to it being quieter. Have you done any comparisons between the A4988 and TMC2208 in this respect?

  24. Hi Peter.
    Please explain me how to add one more more motor and One more device in the ios homekit?
    Thank you

    1. If you are using Homebridge and my accessory plugin, then you just replicate your settings changing the IP of the DIY SmartBlinds device in the accessory plugin. You can add as many SmartBlind devices into the Homebridge setup as you want.

  25. Hi Peter, so I finally got around to trying this out on my blinds but unfortunately it doesn’t work. The stepper motor I’m using just clicks and doesn’t appear to have enough torque to actually move my roller blinds. The torque on my stepper motor doesn’t seem to be very powerful, is there anything settings wise that you think may help. The model number of the stepper motor I’m using is SM-17HS4023. Any help would be appreciated. Thank you.

    1. Hi Ali, roller blinds are typically very heavy. Most solutions that I saw were motors built into the roller itself and not chain operated. Having said that, have you tried adjusting the voltage limiter on the driver board? Perhaps it’s not getting enough power?

      Sounds like to have a good lab setup for testing, you should also get a Nema17 Motor, these are rated at about double the torque of a Nema14, and see if that will operate the blind. I would be very curious to find out. If Nema17 would do the job, making a 3D printable enclosure would not be a problem, it would just be slightly bigger than this one.

  26. TMC2208 driver make blinds absolutely noiseless. I can hear only ball chain rustling.

  27. [If you are using Homebridge and my accessory plugin, then you just replicate your settings changing the IP of the DIY SmartBlinds device in the accessory plugin. You can add as many SmartBlind devices into the Homebridge setup as you want.]

    But I want to use one ESP6288
    and 3 motors with one module. So I want to make separate control of each motor.

    1. I see, in that case you would probably need to connect each of the motor drivers separately to you main nodeMCU. Then rewrite to software to allow you to control them individually. You would need to modify the API as well such that you can send independent commands to each of your blinds.

  28. Hi, I am considering making a smart blind controller. But I wondered how much weight the NEMA 14 can handle before I order my parts. Does anyone have experience with this? I have 2 roller blinds of approximately ~ 2.30m and ~ 0.60m.

  29. Hi Peter.
    Could you explain how to calculate motor spins with HomeKit target position
    I mean Arduino code

  30. David Stoneham says:

    hi like the project do you think it would work with GM4632-370 DC 12V 30RPM High torque Turbo Encoder Motor Worm Geared Motor Reducer Motor, just I built 3 blind opening units and its ok but think yours is better and has HomeKit option, if it would work would it be easy to convert the code to use this motor. just a thought could you include button on front to use manual option to open the blind and everyone loves a led option to give status of the device. thanks in advance will start looking at this very soon.

    1. Hi David, I am sure it’s possible to build a device that uses the GM4632-370 DC motor you listed and that has external buttons and LEDs for feedback. It would need to be a completely new project with a redesigned enclosure.

      If it’s HomeKit integration you are after, then perhaps you can adopt the code for the API from my project, then you would be able to use the HomeBridge plugin as is?

  31. David Stoneham says:

    Thanks Peter will purchase stl files and use yours as a starter and see the options, many thanks for the reply.

  32. David Stoneham says:

    what I am to get is the blinds into home assistant as I run around 60 devices in HA.

    1. Unfortunately I don’t have any experience with Home Assistant. Perhaps one of the raiders here could assist?

  33. Hi!

    Would it be possible for you to create a version of this project with mounting holes on the side of the case? Assuming that the cog side (with the holes) is front (facing me), I would need to have them on the right side of the case.

    I’m not familiar with editing STL files (tried that before) so it would be much helpful for me if you could prepare different versions of this project.

    Thanks!

  34. Hi. Anybody got TMC2208’s to work? What is needed in the sketch? Absolutely great project!

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