Connecting motorised curtain rails to home automation system

[dnb]

In a fit of hopefulness about finishing my build (or insanity, I'm not sure...) I bought a couple of Acrimo motorised curtain tracks in a Black Friday sale so I could evaluate them.

 

For the price I am quite impressed - the whole thing cost not much more than a similar length manual pull cord rail. The curtain rails themselves are designed nicely and implemented well. The battery built in to the motor and supplied small solar panel and is a nice feature to avoid running power (I already have power there, so that was a waste of wire...). The instructions however are less good unless you understand Spanish because the translation to English has some comedy moments. That said, the product doesn't really need too many instructions because the basic set up is fairly intuituve.

 

Of course motorised curtains are silly unless they are automatically controlled somehow. The instructions claim the motors have two RS485 connections via a RJ45 connector, but then don't explain much more about these. The RJ45 connector also has some logical connections to trigger opening and closing. I could use a micro controller connected to Ethernet (Pi Pico or similar since these are cheap enough) to operate the curtains according to the home automation system's commands but it would be fewer components and therefore better if I could work out how the RS485 bus works. I am waiting for a couple of USB RS485 interfaces to arrive in the post, but in the mean time does anyone have experience of these motors?    

[Temp]

Not me but Google AI said.. 

 

"The specific RS485 communication protocol used by Acrimo for their motorized products is generally a proprietary protocol and is not publicly published or standardized"

 

[dnb]

I got to a similar place too, but I know a few of us are curious about such things, and it wouldn't be the only thing that gets reverse engineered in my life so I thought it worth a shot here. Nothing for it than to monitor the bus and see what happens. I believe it will be something fairly standard, so maybe modbus? It's something to keep me amused over Christmas.

 

 

This thread is now the prime source for the information for "acrimo rs485 protocol" according to Google!

Edited Sunday at 22:54 by dnb

[joth]

On 14/12/2025 at 00:02, dnb said:

(I already have power there, so that was a waste of wire...)

No, you'll appreciate having the wire when the battery (or motor) in these fail and you can't get a replacement.

I'd always use wired power and control if I can. Does it not have any option to bypass the battery?

 

In most cases you can use a couple "dry contact" relays to trigger each direction. Electrically equivalent to having a up/down momentary switch to control it. It's just a case of figuring out the pinout on their rj45. If it wasn't that expensive perhaps worth a shot opening it up and tracing the PCB a bit. 

Or email the manufacturer and ask?

[Nickfromwales]

On 14/12/2025 at 00:02, dnb said:

I already have power there, so that was a waste of wire...

Is this a cable back to plant or a local 230v supply that’s off a local circuit? 
 

I always run a unique cable from every single corner of every opening back to a centralised location. 
 

This way I can send AC or DC to each unit, according to what’s needed.

 

If the solar / battery solution works for now then great, but they won’t last forever. If you can match the voltage then you’ve got the option downstream to send it some juice from a transformer, if there’s a dumb cable run to it.

 

If they were cheap enough then maybe the cost to replace them, with like for like by whomever, when the time comes, may be acceptable.

[joth]

Is it not this device?

https://acrimotracks.com/wp-content/uploads/2024/05/Product-manual_EN.pdf

 

Connect pin 1 or 2 to pin 4 for open/close.

It has a 220V ac input connector (figure-8 style) to bypass the solar/battery gumpf.

 

I wouldn't bother with RS485 as i doubt it offers anything more than the dry contact input controls. (It'd be lovely if it reported back current curtain location, especially if it supports tug to open, but I doubt it would)

 

Edited 20 hours ago by joth

[Nickfromwales]

Bingo. 

[dnb]

13 hours ago, joth said:

No, you'll appreciate having the wire when the battery (or motor) in these fail and you can't get a replacement.

I expect I will. So it's not really a waste of cable.

 

13 hours ago, joth said:

Does it not have any option to bypass the battery?

Yes. 230v input and USB C. Both will charge the battery and operate the motor - they seem to have thought it through.

 

13 hours ago, joth said:

In most cases you can use a couple "dry contact" relays to trigger each direction.

This is indeed my fallback plan. But the idea of data is complelling. (See later comments from both of us)

 

13 hours ago, joth said:

Or email the manufacturer and ask?

Done. No response as yet. I'm not planning to open up the motor because it won't tell me about the protocol. The instructions are clear for using the logical inputs, but don't do much else.

 

12 hours ago, Nickfromwales said:

Is this a cable back to plant or a local 230v supply that’s off a local circuit? 

It's as yet uncommitted, taken back to a central location so it can be purposed as needed. I don't like to be caught out if I can plan around it. 

 

9 hours ago, joth said:

Is it not this device?

Yes. I have that page of instructions on paper, so it's not new or helpful for thr RS485 issue. But thanks for posting it up here since it makes it clear which motors we are discussing.

 

9 hours ago, joth said:

I wouldn't bother with RS485 as i doubt it offers anything more than the dry contact input controls.

I want the RS485 because the motor does support tug to open/close and I suspect the motor will report the state over RS485 due to other research, and I want the BMS to know about the state centrally for temperature management.  (I know it doesn't count to anything in building control land.) 

 

9 hours ago, Nickfromwales said:

Bingo. 

Unfortunately not.  And the postman didn't bring me the RS485 thingy today so I can't play without taking the solar data logger apart. Guess I will have to fix one of the pair of Lotus cluttering up the garage instead.

[Nickfromwales]

3 hours ago, dnb said:

Guess I will have to fix one of the pair of Lotus cluttering up the garage instead.

At least it’s not an AMG, or you’d be out there more often

 

Bloody oil cooler this weekend and it’s front end off……again. Gotta love a V8 though lol. 

[Alan Ambrose]

Easiest way to try out is Arduino software or similar and the USB dongle which will present the 485 as standard serial. The manufacturer’s simple protocol is probably documented somewhere, otherwise it’ll be hard to guess unless you have a working example from somewhere. Post up docs here?

[joth]

10 hours ago, dnb said:

I want the RS485 because the motor does support tug to open/close and I suspect the motor will report the state over RS485 due to other research, and I want the BMS to know about the state centrally for temperature management.  (I know it doesn't count to anything in building control land.) 

 

Got it.

 

I expect it's a Tuya motor, extrapolating from their App support info: https://acrimotracks.com/wp-content/uploads/2024/04/Folleto-motor-wifi-EN.pdf

 

A quick search suggests Tuya RS485 is generally running modbus. Dooya is perhaps another brand using Tuya and there's some info on it here  https://community.home-assistant.io/t/dooya-curtain-motor-rs485/140398 (inc links to other pages with some code that has position read back support https://github.com/chuanjiangwong/RS485/blob/665bc856cff307b876acc519dcc02d17ec1dec1d/app/rs485d/src/device/curtain/doya/doya.c) so that's what I'd probably start poking around with (either using that code, or more likely using a generic modbus read/write tool)

 

 

There's also A-OK curtain motors that have a different RS485 (non-modbus) interface, but I think Tuya is the place to start for reasons mentions.