[BK7231N/CBU] Modemix MOD001 WiFi Tuya shutter controller

p.kaczmarek2 3741 0

TL;DR

Modemix MOD001 is a Tuya Wi‑Fi roller shutter controller built around a BK7231N CBU module and two relays for up/down motor control.
Inside, it is a 1:1 copy of the MOD003 dual relay board, with the same PCB and only different firmware and housing markings.
The controller costs about PLN 75 in Polish online stores.
Flashing OpenBK7231T_app with BK7231GUIFlashTool worked without problems, and the module was freed from the cloud.
Blind configuration is not covered because no blind was available for testing, so only the teardown and firmware swap are shown.

AI summary based on the discussion. May contain errors.

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Identical PCB to MOD003 with shutter control
Post #1 20582252 16 May 2023 10:39

Today we are programming a device that is confusingly similar to the previously discussed MOD003 double relay and differs only in the software and markings on the housing. Even inside the PCBs are identical. The aforementioned MOD003 had two relays and supported the connection of two buttons, but it simply controlled the light - the product from this topic is something else, it is a roller shutter controller, i.e. you can connect two astable buttons (one to move the roller shutter up, the other down) and two relays from the inside control the motor in such a way that they are never both activated at the same time and the shutter opening/closing time is controlled and limited by the application. The Tuya application supports the calibration of roller shutters and you can set the opening / closing time, which should be selected individually after installing the controller, but here I will focus only on showing its interior and changing the firmware.

By the way, it's worth learning about related topics. About MOD003:
https://www.elektroda.pl/rtvforum/topic3976806.html#20572374
General topic about the configuration of blinds in OBK (not mine, work by one of our users):
https://www.elektroda.pl/rtvforum/topic3972935.html
The firmware repository that we will upload to this product to free it from the cloud:
https://github.com/openshwprojects/OpenBK7231T_App
Its documentation:
https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/README.md
UART programmer:
https://github.com/openshwprojects/BK7231GUIFlashTool

Buying a controller
The product costs about PLN 75 in Polish online stores. It is sold by various sellers, here I describe the art available under the Modemix logo.

The product was given to me by a reader so that I could change the firmware for him, thank you for sharing the equipment for the topic. After the change, the product returns to the reader.
This is how it looks in the application:

Dimensions:

And assembly:

The roller shutter is controlled by switching on either L1 (movement up) or L2 (movement down). This is done by pressing the S1 or S2 buttons. The firmware does the rest. There are no hardware sensors to check if the blind is fully opened, etc. In the Tuya application, you can only calibrate the blinds by specifying the working time needed to fully open and close the blinds.

Kit Contents
What do we get for PLN 75?

This time they didn't even give mounting screws, which is a pity.

The interior of MOD001
We pry the cover and remove the hooks, then you can remove the PCB:

The PCB comes out pretty hard. The WiFi CBU module with BK7231N is on an additional board, on it there is also a diode indicating the WiFi status and a pairing button.

For the rest... it's a 1:1 module MOD003 , only with different firmware. PCB is the same.

If in doubt, please refer to the topic MOD003 .

Bottom of the PCB:

You can see AMS 1117 3.3V - LDO regulator, and the system on which the power converter is made - KP15051SP.

MOD001 programming
Identically as in the case of MOD003, we only solder RX, TX, ground and 3.3V:

In practice it looks like this:

It's just that in the photo I used a yellow cable for ground, and a brown one for power.
Here is the whole system, with 3.3V power supply from the LDO:

We flash this:
https://github.com/openshwprojects/BK7231GUIFlashTool
The procedure is simple:
1. disconnect the power supply from the module
2. Connect the USB to UART converter to the PCB
3. start the backup and write process in BK7231GUIFlashTool, then waiting for the "getting bus" will start
4. connect this power supply to the module
5. then the module programming will start
By the way, it is worth giving a list of his departures once again:
- P7 - WiFi LED
- P8 - pairing button
- P9 - relay 1
- P17 - relay 2
- P24 - button 1
- P26 - button 2
OBK template:

Code: JSON
Log in, to see the code

Summary
This was a description of changing the firmware of the MOD001 Modemix roller shutter controller. However, it did not contain a description of its configuration, because at the moment I do not have a blind for it, and I changed the firmware for one of the readers. After all, I think that the control of roller shutters will be explained soon - OpenBeken contains a scripting system that is so advanced thatThat interlock relays can be implemented without editing the code, as well as detailed timers for opening/closing roller shutters. Details soon, for now that's it, the most important thing is done - the module is freed from the cloud, now you can have fun.
The firmware change went without any problems, and it is obvious that there are basically no differences between the two-channel smart switch (controlling two lights through two receivers) and the roller shutter controller. Hardware is the same. Only the software differs (e.g. in the roller shutter controller, it makes sure that both relays are not switched on at the same time).
NOTE: In the meantime, more or less during the work on this topic, one of the OBK users himself described the configurations of roller shutters in this system (in conjunction with Home Assistant). Therefore, I recommend you to read the topic below:
https://www.elektroda.pl/rtvforum/topic3972935.html

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[BK7231N/CBU] Modemix MOD001 WiFi Tuya shutter controller

FAQ

TL;DR: The PLN 75 Modemix MOD001 uses a BK7231N CBU module; “hardware is the same” as MOD003, but shutter-safe firmware changes relay behavior. This FAQ helps OpenBeken users flash, map, and understand the Tuya shutter controller without cloud control. [#20582252] Why it matters: Correct UART flashing and relay interlock prevent cloud lock-in and avoid unsafe simultaneous motor directions.

Feature	Modemix MOD001 shutter controller	Modemix MOD003 double relay module
Main use	Roller shutter up/down motor control	Two-channel light or load control
Hardware	Same PCB and CBU BK7231N module	Same PCB and CBU BK7231N module
Relay behavior	Firmware prevents both relays turning on together	Two relays act as separate outputs
Inputs	S1 and S2 astable shutter buttons	Two button inputs
Key difference	Software and housing markings	Software and housing markings

Key insight: MOD001 is essentially MOD003 hardware with shutter-specific firmware. After flashing OpenBeken, safe operation depends on correct pin mapping and software interlock. [#20582252]

Quick Facts

The Modemix MOD001 described in the thread cost about PLN 75 in Polish online stores, but the kit did not include mounting screws. [#20582252]
The WiFi board is a CBU module with BK7231N, plus a WiFi status LED and a pairing button. [#20582252]
UART programming uses RX, TX, GND, and 3.3V; the author powered the board from the 3.3 V LDO during flashing. [#20582252]
Internal power parts include an AMS1117 3.3 V LDO regulator and a KP15051SP converter IC. [#20582252]
OpenBeken mapping uses 6 pins: P7 WiFi LED, P8 pairing button, P9 relay 1, P17 relay 2, P24 button 1, and P26 button 2. [#20582252]

How do you flash OpenBeken firmware to a Modemix MOD001 WiFi Tuya shutter controller with a BK7231N CBU module?

Flash OpenBeken by wiring UART, starting BK7231GUIFlashTool, then powering the BK7231N board.

Disconnect power from the MOD001 module.
Connect USB-UART to RX, TX, GND, and 3.3 V.
Start backup/write in BK7231GUIFlashTool, wait for “getting bus,” then connect power. The author used the OpenBK7231T_App firmware and reported that the firmware change went without problems. This procedure frees the shutter controller from Tuya cloud control. [#20582252]

What is the Modemix MOD001 Smart Curtain Module and how does it control roller shutters?

The Modemix MOD001 is a WiFi Tuya roller shutter controller using two relays and two astable buttons. It switches L1 for upward movement or L2 for downward movement. S1 and S2 trigger those directions. The firmware handles the rest and prevents normal shutter operation from behaving like two independent lights. The thread describes no physical end-position sensors inside the controller. Position control therefore relies on calibrated travel time in the app or later firmware logic. [#20582252]

What is a BK7231N CBU module used for in Tuya-based WiFi shutter controllers?

A BK7231N CBU module provides the WiFi and MCU platform inside this Tuya-based shutter controller. “BK7231N CBU module is a WiFi microcontroller board that runs the device firmware, exposes GPIO pins for relays, buttons, and LED status, and can be reflashed over UART for OpenBeken control.” In MOD001, the CBU sits on an additional board with the WiFi LED and pairing button. [#20582252]

Which RX, TX, GND, and 3.3V connections are needed to program the MOD001 over UART?

Program the MOD001 by soldering four UART connections: RX, TX, ground, and 3.3 V. The thread shows these points on the same PCB layout as MOD003. The author notes one photo used yellow for ground and brown for power. Power came from the 3.3 V LDO during the shown flashing setup. Do not use mains power while soldering or probing these UART points. [#20582252]

How does BK7231GUIFlashTool work when backing up and flashing a BK7231N device?

BK7231GUIFlashTool waits for the BK7231N boot handshake, then performs backup and write operations. The thread’s sequence starts with the module unpowered. After connecting USB-UART, start backup and write. The tool then waits at “getting bus.” Apply 3.3 V power at that moment. The programming process should start after the boot window appears. This timing matters because the bootloader must be caught immediately after power-up. [#20582252]

What OpenBeken pin template should be used for the Modemix MOD001 shutter controller?

Use the OpenBeken template named “MOD001 Smart Curtain Module” for vendor ModeMix, chip BK7231N, and board CBU. The template maps P7 to WifiLED_n, P8 to Btn_Tgl_All, P9 to Rel;1, P17 to Rel;3, P24 to Btn;1, and P26 to Btn;3. It also identifies the model as MOD001. The image URL in the template points to the photographed UART flashing setup. [#20582252]

MOD001 vs MOD003: what are the hardware and firmware differences between the Modemix shutter controller and double relay module?

MOD001 and MOD003 use identical PCBs, but they run different firmware and carry different housing markings. MOD003 works as a double relay module for two light outputs. MOD001 works as a shutter controller, so its firmware treats the two relays as opposite motor directions. The author states that the difference is basically software. The shutter firmware ensures both relays do not activate at the same time. [#20582252]

How are the MOD001 pins P7, P8, P9, P17, P24, and P26 mapped in OpenBeken?

The MOD001 maps six BK7231N pins to OpenBeken roles. P7 is WifiLED_n. P8 is Btn_Tgl_All. P9 is relay 1. P17 is relay 3. P24 is button 1. P26 is button 3. These assignments match the template published for the ModeMix MOD001 Smart Curtain Module. Correct mapping is required before shutter logic can safely control up and down movement. [#20582252]

How does the Tuya app calibrate a roller shutter controller without physical position sensors?

The Tuya app calibrates the shutter by using travel time, not physical position feedback. The thread states there are no hardware sensors to confirm that the blind is fully opened. The user sets the working time needed for full opening and closing. That timing must be selected individually after installing the controller. This means accuracy depends on the shutter motor and real installation conditions. [#20582252]

What is relay interlock in a roller shutter controller and why is it important for motor safety?

Relay interlock prevents both shutter-direction relays from turning on at the same time. “Relay interlock is a control rule that blocks conflicting relay outputs, ensuring an up relay and a down relay cannot energize together, which protects a shutter motor from simultaneous opposite-direction commands.” In MOD001, the original shutter firmware performs this function. OpenBeken must reproduce it through configuration or scripting. [#20582252]

How can OpenBeken scripts be used to prevent both shutter relays from turning on at the same time?

OpenBeken scripts can implement interlock by enforcing one active relay at a time. The author states OpenBeken has an advanced scripting system. He also notes that relay interlock can be implemented without editing source code. For MOD001, that means scripts can turn off the opposite relay before enabling movement up or down. The thread does not provide a finished shutter script, but it points to a separate blind-configuration topic. [#20582252]

What should you check if a BK7231N module does not enter flashing mode and BK7231GUIFlashTool stays on getting bus?

Check power timing, UART wiring, and the 3.3 V supply if BK7231GUIFlashTool stays on “getting bus.” The thread’s working method applies power only after backup/write starts. RX and TX must be connected to the correct UART points. Ground must be common between the USB-UART adapter and the board. The module should receive 3.3 V, not an arbitrary external voltage. A missed boot window can stop programming from starting. [#20582252]

What power supply components are inside the Modemix MOD001, such as AMS1117 3.3V and KP15051SP?

The MOD001 contains an AMS1117 3.3 V LDO regulator and a KP15051SP-based power converter section. The AMS1117 supplies the 3.3 V rail used by the BK7231N CBU module. The thread identifies both parts on the bottom of the PCB. The author also powered the flashing setup from the 3.3 V LDO. These parts sit inside a mains-powered shutter controller, so isolation precautions matter. [#20582252]

How can the Modemix MOD001 be integrated with Home Assistant after replacing Tuya firmware with OpenBeken?

Integrate the MOD001 with Home Assistant by replacing Tuya firmware with OpenBeken, then configuring shutter behavior there. The thread does not include a full Home Assistant setup. It explicitly recommends a separate OpenBeken blind-configuration topic connected with Home Assistant. After flashing, the key work is mapping P7, P8, P9, P17, P24, and P26, then adding shutter logic and relay interlock. [#20582252]

What safety precautions should be followed when opening and programming a mains-powered Tuya roller shutter controller?

Disconnect mains power before opening, soldering, or programming the MOD001 controller. The device controls L1 and L2 motor outputs and contains an internal mains power supply section. During UART flashing, use only RX, TX, GND, and 3.3 V on the low-voltage side. Avoid energizing both relays together, because shutter motors use opposite directions. Reassemble the enclosure before normal installation behind a wall switch or shutter control box. [#20582252]