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Wanting to have a motorized blinds connected to my smart home and never have it done before I would like to double check several potentially obvious questions...

First of all, the blinds manufacturer suggests installing blinds with motor DV24DH/L (most likely Dooya: dv24dh.png) with the power source of 12 V 2 A and a mechanical switch (marked as DC126, DC127, DC128 in their manuals) that, according to the pictures, reverses input polarity (3-way switch with 6 total contacts, visible at the top of [similar motor manual]). I have found international version of the manual of the similar motor DM25DB for more information.

My goal is to open/close/stop blinds using NodeMCU or similar.

Is it correct that this is a really DC motor where you controls the rotation direction applying input from the power source in straight and reversed polarity? Is there any visible signs except of two-wire motor input and mechanical switch that obviously reverses input?

If yes, can it be controlled with two SPDT relay, as shown in this answer?

Any drawbacks of controlling this motor with a L298N?

L298N cons I see:

  • I know it has ~2 V drop so the motor will be powered with 10 V instead of 12 from the original power source, and it is unknown whether internal motor electronics (assuming there is something inside except the motor to provide end-stop and resistance-stop functions) may not work properly from 10 V. Is it safe to replace the original power source with a LED strip transformer that should have adjustable 12-14 V 2 A output and use it with 14 V?

L298N pros I see:

  • From what I see in the datasheet it takes care of the delay during direction switching and back EMF in L298N module with diodes, something that I should probably do separately with SPDT relay.

Any questions and suggestions are appreciated.

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    \$\begingroup\$ There is a lot of raw guess work in this question, can you find out the motor start and stall current? \$\endgroup\$
    – Jens
    Jul 23, 2022 at 18:02
  • \$\begingroup\$ Try it with 10 V first. I see a high probability it will work just fine just a tad bit slower. Otherwise a 14 V supply sounds like a reasonable solution. \$\endgroup\$
    – winny
    Jul 23, 2022 at 18:21
  • \$\begingroup\$ It really appeared a DC motor where polarity changes the rotation direction. There is some electronics inside the tube apparently to stop the move when lines are detached. Now it's working with two-SPDT schema and its native power source. Unfortunately, I have no devices to measure inrush current so decided it is the safest way at least for now. \$\endgroup\$
    – Larry0ua
    Sep 25, 2022 at 12:15

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The sketch you linked to is close. Try a DPDT center off switch wired the same way and it will give your forward, off, reverse. Depending on the switch there could be enough delay when going through the center position to allow the motor field to partially decay. This will be possibly the most cost effective way.

My preference to control it remotely just use use one of the many BTS7960 bridge modules available. Currently I have about a dozen of these operating in my smart home, mainly controlled by Arduino 5V. If you want to use 3V3 you will need a level translator. They are a nice part they stay cold but my worse case is 10A not close to the 43A rating. They can be purchased for less then $10.00 delivered to your door in the US. They have built in protection etc and the logic is 74HC.

Caution: Internally the logic ground and power ground are connected. There is a low voltage cutout if the motor voltage drops I think below about 8V. These will allow PWM (seperate input if wanted) forward and reverse. I use them as a Dual LED driver, I have several driving about 20 Amps each side totally independent of the other and nice part driven both high and low. They still stay cool.

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