Edit: After doing more research, it seems simply reversing the DC polarity would do the trick as explained here: https://www.precisionmicrodrives.com/content/are-dc-motors-reversible

This can be accomplished with a SPDT relay apparently, or with 2 regular relays. Thus, I see the following options:

  1. Tasmota flashed Sonoff R3 Pro relay (https://www.itead.cc/smart-home/sonoff-4ch-r3-pro-r3.html)
  2. Any regular 2 channel relay (http://yourduino.com/sunshop//index.php?l=product_detail&p=218)
  3. Use an off the shelf SPDT relay (https://www.seeedstudio.com/Grove-2-Channel-SPDT-Relay.html)

I'd say option 1 is the best way to go, since I won't have to bother with supplying power to the microcontroller and I can just mount everything on a DIN rail in my central control box. Drawback is obviously an older platform with inherent security risks. Believe I can mitigate those with restricting role of Sonoff device on AWS IoT core though.

Am I on the right track here?


I'm trying to build a low-cost PE-film greenhouse with as much automation as possible to reduce labor cost. Ventilation control by manually rolling up the film on the side of the greenhouse with a hand crank is one of the largest drivers of cost. Automating this seems like a low-hanging fruit, since there are tons of relatively cheap purpose-made greenhouse control motors out there on Alibaba.

Before buying though, I'd like to know what my options are when it comes to remote control. The ones I've seen are either 2 wire or 3 wire on DC24v and all of them come with 2 knobs to control maximum rollup/rolldown (under cover marked in red on schematic). There seems to be a way to control them, as some of the them come with manual control systems as in the pictures below.

Greenhouse overall will be controlled through AWS IoT cloud with ESP32-S2 units connected to sensors and control systems across the greenhouse, so an approach using an ESP32 driving the motor control is my preference, but open to any other ways too.

Any help or pointers would be greatly appreciated. Thank you!

Example of low-cost greenhouse film roll motor Another view of low-cost greenhouse film roll motor Attached to the greenhouse Schematic


1 Answer 1


You could use a 2 CH RF Operated Relay board with remote control.

You may get models prewired for DC Motor Reversing Control.

If you don't, the relays may be wired as shown.

enter image description here

The motor would be controlled by operating 2 buttons on the remote.


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