[Teardown][BK7231N] Tuya Wi-Fi+RF Curtain Module - Compatibility with Rocker Switches

MarcusE 31 Dec 2023 17:12 1 3060 Cool? (0)

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TL;DR

A Tuya Wi‑Fi+RF Curtain Module for shutters and curtains uses a CB2S module with a BK7231N SoC.
Rear-side disassembly reveals stacked PCBs and the BK7231N-based controller inside the no-name unit.
The board includes 2× relays rated at 10A and a 433MHz RF receiver, plus a supplied remote control.
A tri-stable rocker switch with mechanical interlock confuses the firmware, which waits for STOP before running the motor.

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Hello,
this is my second post here, so please be gentle...( :-)

)

I bought this device on AliExpress - as my second post here.
It is a (single) controller for shutters, curtains etc.
Data as found:
- Wifi on Tuya plus RF receiver on 433MHz
- Remote control in Scope of supply
- Brand: NoName (not found)
- Product-Name: Wi-Fi+RF Curtain Module
- SoC: CB2S (BK7231N)
- 2x relays of 10A

Disassembly is quite easy from rear side with small screwdriver - self explanatory.
Here I removed the stacked PCBs to see/show the SOC itself.

Now to my request: similar as in my earlier post .
The wall switch I have is a rocker switch with mechanical interlock and TRI-stable status (UP/OPEN - STOP - DOWN/CLOSE). The motor has two end-switches integrated. When the wall switch is pressed, the motor will run until end switch cut out - but wall switch can remain pushed. Sorry, find it hard to explain...

Like that, I don't have buttons for up/(stop/)down, but steady/stable switches instead.

Now, the 'smart' controller expects a button function in the wall switch and does not understand the wall switch rocker function.
Problem: When I press UP or DOWN on the wall switch, controller waits for me to press STOP first, then starts the motor.
This has a low WAF...

I am wondering, if there is a way to solve this within TUYA firmware - would be sufficient for me as IObroker already can control it.
Or should I flash the CBU / BK7231N to openBK to solve this problem, which I did not do by now - I only flashed some ESPs to Tasmota.
Or should I replace the CBU with a ESP32-C3 with Tasmota.

Anyone with shutter experience around?

Many thanks!!

BR Marcus

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p.kaczmarek2 01 Jan 2024 09:46

OpenBeken is fully scriptable so it should be possible to achieve it, but it would require some scripting. We already have shutters script so you might want consider adapting it: https://www.elektroda.com/rtvforum/topic3972935.html I... [Read more]

FAQ

TL;DR: For owners of CB2S/BK7231N curtain modules with 433 MHz RF and 2 relays, OpenBeken is the most credible fix because it is, as an expert wrote, "fully scriptable." It can be adapted for a tri-stable UP-STOP-DOWN rocker, while the stock Tuya logic expects momentary wall inputs and can wait for STOP before moving. [#20886028]

Why it matters: This FAQ helps shutter and curtain installers choose the least disruptive path when a Tuya wall input conflicts with a latched mechanical rocker.

Option	What the thread says	Fit for tri-stable rocker switch
Keep Tuya firmware	No confirmed solution in the thread	Unclear
Flash OpenBeken	Possible, but needs scripting or shutter-script adaptation	Best-supported option
Replace CB2S with ESP32-C3 + Tasmota	Mentioned only as an idea	Not validated in the thread

Key insight: The real mismatch is input logic, not motor power. The module expects button-like pulses, but the wall switch stays latched in UP or DOWN, so OpenBeken scripting is the only solution explicitly supported in the discussion. [#20886028]

Quick Facts

The module is a single shutter or curtain controller with Wi-Fi + 433 MHz RF, and the RF remote is included in the package. [#20885325]
Hardware identified in the teardown: CB2S module, BK7231N SoC, and 2 relays rated at 10 A each. [#20885325]
The existing wall control is a tri-stable rocker with mechanical interlock: UP/OPEN - STOP - DOWN/CLOSE. [#20885325]
The motor already has 2 built-in end switches, so it runs until an end switch cuts out even if the wall rocker remains pressed. [#20885325]

How can I make a Tuya Wi‑Fi+RF Curtain Module with a CB2S/BK7231N work correctly with a tri-stable mechanically interlocked rocker switch?

Flash OpenBeken and adapt its shutter logic for a stable UP-STOP-DOWN rocker. The expert answer says OpenBeken is "fully scriptable," and the existing shutters script is the recommended starting point. The stock Tuya behavior described here does not match a latched 3-position wall switch, so scripting is the clearest path discussed. [#20886028]

Why does this Tuya curtain controller wait for a STOP input before moving the motor when used with a stable UP-STOP-DOWN wall rocker switch?

It waits because the controller expects momentary button inputs, not a latched rocker state. In this installation, the wall switch can stay in UP or DOWN, but the module still behaves as if it needs a separate STOP event first. That logic mismatch causes the low-WAF behavior described by the owner. [#20885325]

What changes in Tuya firmware could help a shutter or curtain module handle steady-state rocker switches instead of momentary buttons?

This thread does not show a confirmed Tuya firmware change that solves it. The owner asks whether Tuya firmware can be adjusted, but the reply only confirms OpenBeken scripting as a viable route and explicitly says the responder does not know whether Tuya itself can do it. [#20886028]

How do I flash a CB2S or BK7231N-based curtain module to OpenBeken for shutter control customization?

You cannot get the flashing procedure from this thread alone. The discussion confirms that OpenBeken can be used for this kind of curtain module and customized with scripting, but it does not provide wiring, tool names, pin mapping, or a step-by-step flash method for CB2S or BK7231N. [#20886028]

What is OpenBeken, and how is it used on BK7231N or CB2S smart curtain modules?

"OpenBeken" is firmware that replaces the stock device software, adds scripting, and lets you customize control logic. In this thread, it is presented as a practical way to adapt a BK7231N or CB2S curtain controller to non-momentary wall switches by reworking shutter behavior with scripts. [#20886028]

What is a tri-stable rocker switch with mechanical interlock in shutter or curtain installations?

"Tri-stable rocker switch" is a wall switch that holds three fixed positions, controls motor direction, and uses mechanical interlock to prevent opposite commands at the same time. Here, the positions are UP/OPEN, STOP, and DOWN/CLOSE, and the switch remains latched until changed manually. [#20885325]

Which approach is better for a Tuya curtain controller with rocker switches: adapting OpenBeken scripts or replacing the CB2S with an ESP32-C3 running Tasmota?

Adapting OpenBeken scripts is the better-supported approach in this thread. The responder explicitly recommends OpenBeken because it is scriptable and already has a shutters script, while the ESP32-C3 plus Tasmota path appears only as the owner's untested replacement idea. [#20886028]

How can I adapt the existing OpenBeken shutters script for a Wi-Fi+RF Curtain Module with two relays and end-stop motors?

Start by adapting the existing OpenBeken shutters script to the module’s 2-relay layout and the motor’s built-in end switches. The expert reply says the shutters script already exists and is the script to consider adapting. In this case, the script must interpret stable rocker states correctly instead of waiting for separate stop-button presses. [#20886028]

What should I check before using a 433 MHz RF plus Wi-Fi curtain module with a shutter motor that already has built-in end switches?

Check the wall-switch type, the motor end-switch behavior, and the relay arrangement first. This module combines Wi-Fi with 433 MHz RF, uses 2 relays rated at 10 A, and the motor already stops on 2 built-in end switches. If the wall switch stays latched, the controller logic may still mis-handle direction changes. [#20885325]

In what way do built-in motor end switches affect the behavior of smart shutter relays when the wall switch stays latched in UP or DOWN?

Built-in end switches stop the motor at travel limits, but they do not fix incorrect wall-input logic. In this setup, the motor runs until an internal end switch cuts out, even if the rocker remains pressed, yet the smart module still expects button-style control and can wait for STOP before moving. [#20885325]

What are the most common compatibility problems between Tuya curtain modules and non-momentary wall switches?

The main problem is input-mode mismatch between latched switch states and button-oriented firmware. Here, a tri-stable rocker with mechanical interlock stays in UP or DOWN, but the Tuya module expects a press sequence and may demand STOP before starting. That creates confusing local control even when app control works. [#20885325]

How do I safely disassemble a no-name AliExpress Wi-Fi+RF Curtain Module to identify the CB2S or BK7231N SoC?

Open it from the rear with a small screwdriver, then separate the stacked PCBs to view the SoC. 1. Pry the rear side carefully. 2. Remove the stacked boards. 3. Inspect the module marking to confirm CB2S and the BK7231N chip. The owner describes this teardown as quite easy from the rear side. [#20885325]

Why might stable rocker switches feel less intuitive than momentary buttons for curtain control, and how does that impact user experience?

They can feel less intuitive because the switch position and the controller’s expected command sequence do not match. The responder directly questions whether steady or stable buttons are a good choice for curtains, and the owner already reports poor household acceptance because movement may not start until STOP is pressed first. [#20886028]

What is the difference between a CB2S module and the BK7231N chip inside it when choosing firmware or flashing tools?

The thread identifies CB2S as the module and BK7231N as the SoC inside it. That distinction matters because the teardown shows both names: the product uses a CB2S-based board, and the silicon visible on it is BK7231N. The discussion treats both as relevant when considering OpenBeken replacement firmware. [#20885325]

What troubleshooting steps help when an iObroker-controlled Tuya shutter module works remotely but behaves incorrectly from the physical wall switch?

Verify the physical input type before changing automation logic. If iObroker control already works, focus on the wall switch because the owner states remote control is sufficient but the physical rocker causes the wrong STOP-before-move behavior. The thread’s practical next step is OpenBeken with shutter-script customization for the latched switch. [#20886028]

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