DIY motorized blinds using Moteino, for $40

[snorp]

I'm using the Moteino to automate my tilt blinds, and posted about it here: http://snorp.net/2016/05/20/blinds-controller.html

Thanks a lot to TomWS, perky, and others on this board who helped me out. I've had a lot of fun, and can't wait to do something else with the Moteino!







https://www.youtube.com/watch?v=yUh9PRCVxMo

[snorp]

One thing I don't talk about in that post that folks here might be interested in is a library I created to abstract away much of the boilerplate associated with creating a new "node" -- https://github.com/snorp/Node

Included in this library is a (basic) common message format, automatic waking of sleeping nodes, battery monitoring, and remote node address reassignment.

[Felix]

Such a nice implementation, I will try to post this on the blog when I find the time.
Thanks very much for sharing it with the forum!

[TomWS]

Good job!  And nice posting!  Well documented, including your learning, EXCELLENT!

Tom
BTW, I'm using that motor on a project that I hope to be posting soon (if it works 
As I said when you first pointed it out, the Actuator bargain of the Century!

Tom

[luisr320]

Nice project. Thanks for sharing.

[joelucid]

Well done! 

[Roger2016]

Very nice project!  Thanks for sharing!  If nothing else your link introduced me to the Moteino for which I have a lot of uses. 
I'm starting work on this project now for my house.  I have about 10 blinds I want to control all similar to the ones you have.  Do you find those tiny stepper motors have enough grunt to reliably control those blinds?  I was loosing steps on my initial test, but I could have speed and acceleration values incorrect.  Unless I'm missing something and this is probably a dumb newbie question.  I see you have posted a library, but I don't see an .INO file.  How do I use your library?

Thanks!

[snorp]

I'm starting work on this project now for my house.  I have about 10 blinds I want to control all similar to the ones you have.  Do you find those tiny stepper motors have enough grunt to reliably control those blinds?

It can't close the blinds as tightly as the manual worm gear mechanism, but I find it does well enough. If I ran across a cheap worm gear actuator that was small enough to fit in a 2" rail, I'd probably give it a try. One thing you could try first is to convert the 28BYJ motors into a bipolar motor. There are some instructions for how to do that here: http://www.jangeox.be/2013/10/change-unipolar-28byj-48-to-bipolar.html. The author there claims about double the torque after this modification.

For my issue (closing the blinds tighter), I don't think it will work, because the 'braking' force of the motor when at rest would not change. The worm gear excels at this by providing a mechanical solution.

I was loosing steps on my initial test, but I could have speed and acceleration values incorrect.  Unless I'm missing something and this is probably a dumb newbie question.  I see you have posted a library, but I don't see an .INO file.  How do I use your library?

I'm using platformio instead of the (shitty) Arduino IDE. Just put the Node and RFM69_WL checkouts into ~/.platformio/lib if you are on Mac/Linux. No idea on Windows, but there will be some documented path for platformio libs to go.

[Roger2016]

Thanks Snorp!

I already had the bi-polar conversion on my radar.  We could also add a second motor on the other end of the shaft running synchronized but opposite rotation.  That would double the breaking as well as the torque.  Of course we could add a physical spring loaded brake where we release the brake then rotate the shaft.  The spring will hold the brake a motor or solenoid would release the brake so it would only take power momentarily to release the brake.

[snorp]

Thanks Snorp!

I already had the bi-polar conversion on my radar.  We could also add a second motor on the other end of the shaft running synchronized but opposite rotation.  That would double the breaking as well as the torque.  Of course we could add a physical spring loaded brake where we release the brake then rotate the shaft.  The spring will hold the brake a motor or solenoid would release the brake so it would only take power momentarily to release the brake.

All good points! The spring-loaded brake is a good idea. I'm not great with the mechanical bits, so I didn't try anything clever there. I really think a worm gear would solve all of the problems -- more torque, and built-in braking -- but I just haven't run across anything that looks viable. Most of the coupled motor/gear things aren't steppers either so you'd need to have some encoding on the shaft. Not impossible, of course, but adds more complexity.

[ramshaklez]

Looking to use your basic solution to control a motor with a Moteino except rather than opening/closing slats I want to raise/lower the entire blind. I am not sure if I should get a DC motor or a Stepper for this. I realize I'll need a lot of torque.

Also, I am not really sure how to get the motor to automatically stop when the blinds are fully open/closed. Any thoughts are appreciated!!

[ChemE]

Also, I am not really sure how to get the motor to automatically stop when the blinds are fully open/closed. Any thoughts are appreciated!!

Limit switches are the standard way to limit the travel/swing of mechanical operators like this.

[TomWS]

Joe Lucid turned me on to this motor:
https://solarbotics.com/product/gm3/

Lots of torque, inexpensive, runs on 3-4V, and, although a bit fast for control applications, can be PWM'd down to 1-2 RPM at the shaft.  It's also relatively quiet.

Easy to drive unipolar if you don't need to reverse direction or with an inexpensive H-Bridge if you do.

Tom

[perky]

Thanks for that link Tom, I've got a project that uses a servo as an actuator requiring a movement of about 13mm with several kg force, I'd have to put end stop switches and an H-bridge but this could reduce the cost by quite a bit

Mark.

[WhiteHare]

Also, I am not really sure how to get the motor to automatically stop when the blinds are fully open/closed. Any thoughts are appreciated!!

Perhaps you can identify it by monitoring for a signature change in the current flow.