[WBR2/W701] Unsupported MaxCom Smart Breaker SHSB111W10

p.kaczmarek2 21 May 2023 14:02 5 3459 Cool? (+5)

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TL;DR

Teardown of the Maxcom SHSB111W10 smart breaker, a cheap Tuya-style switch that looks like a Sonoff classic but uses a WBR2/W701H Wi‑Fi module instead of ESP.
Inside it uses a 5V 005DC-HS QYT73 relay, fuse, varistor, input filter, BP2905 step-down supply, and an AMS1117-3.3V regulator.
The breaker sells for as little as 40 PLN, and its module pinout matches TYWE2S-compatible boards such as ESP-02S, CB2S, and WR2.
An ESP-02S swap could make Tasmota possible, but the SHSB111W10 is not supported by the firmware yet and still is not truly cloud-free.

Summary generated by AI based on the discussion content.

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Hello, today a short presentation of another Tuya gadget, this time combined with a warning, because this gadget is built on a WiFi chip for which there is no open software available at this moment. Inside the SHSB111W10 we find the WBR2, or W701H chip, a KM4-core microcontroller with 256KB SRAM and 2MB Flash. I will describe its internals here, and the possibility of swapping the WiFi module with another one from ESP, so that Tasmota can be uploaded.

Purchase SHSB111W10 .
This Maxcom gadget is very cheap, you can buy it for as little as 40 PLN, and it is available in various Polish online shops:

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From the outside it resembles the Sonoff classic, but there is no ESP inside.

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This is what it looks like in practice:

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Instructions, including a description of the pairing:

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Screw terminal protectors:

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Interior of SHSB111W10 .
The casing is held in place by snaps.

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The actuator is a relay at 5V, 005DC-HS QYT73, besides that you can also see a fuse, a varistor, an input filter, and part of a transformerless power supply, more precisely a small step-down converter.
The underside of the PCB will tell us more:

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The power supply mentioned is implemented on a BP2905, I couldn't find its datasheet, but it's probably a similar circuit to this one:

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Apart from that, there is also an AMS1117-3.3V, LDO regulator.
Well, and a WiFi module:

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Outputs:

3V3

	Pin number	Symbol	IO type	Function	Function
1	3V3	/	Power supply pin (3.3V)
2	A19	I/O	GPIOA_19, PWM hardware, IC Pin40
3	GND	P	Power supply reference ground
4	A18	I/O	GPIOA_18, PWM hardware, IC Pin39
5	A13	I/O	GPIOA_13, UART0_RXD, which is used as a user-side serial interface pin
6	A17	I/O	GPIOA_17, hardware PWM, IC Pin38
7	A14	I/O	GPIOA_14, UART0_TXD, which is used as a user-side serial interface pin
8	A20	I/O	GPIOA_20, common GPIO, IC Pin1
9	A12	I/O	GPIOA_12, PWM hardware, IC Pin26
10	EN	I/O	Enabling pin, which works at the high level and is pulled up and controlled by a user externally
11	A11	I/O	GPIOA_11, hardware PWM, IC Pin25

[/table:61afb0b75e] .
The outputs are compatible with TYWE2S, so you can swap the WiFi module for one with ESP<spanclass="notranslate"> .

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The ESP-02S can be purchased for a dozen gold:

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This is a very popular module format, compatible by pinout with CB2S, FL_M99_V1, TYWE2S, TYZS6, TW-02, WR2, WB2, WBR2, WR2E, WB2S, WA2 andXT-BL02.

Summary .
The product is cheap, but so what? It won't make it cloud free anyway. This is only for Tuya supporters.
The best thing would be to get something from ESP, e.g. buy the original Sonoff, after all it's not expensive either, so no need to complicate things.
Or use e.g. Qiachip smart Switch which is on BK7231N and you can upload OpenBeken:
https://www.elektroda.pl/rtvforum/topic3874289.html
Alternatively, you could solder out the WBR2 and solder in an equivalent on an ESP, e.g. ESP-02S or compatible, but this is unlikely to be financially worthwhile.
Anyway - the SHSB111W10 is not supported by my firmware at the moment, but I intend to look into it soon.

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p.kaczmarek2 wrote 14682 posts with rating 12708 , helped 656 times. Been with us since 2014 year.

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piotrszulc1 04 Dec 2023 18:00

As a warning - I also came across this chip in an Ineox LZWW-3 power strip. Cloudcutter didn't work, so I decided to open it up, and there it is, the W701H, plus it's on an unmarked module, so you don't... [Read more]

rudolfbyker 15 Jun 2024 14:41

Is it OK to post in English here? Or should I create a new topic on the English forum? In South Africa, this exact device is sold at Communica https://www.communica.co.za/products/smart-switch-basic-wifi-tuya-10a?variant=39250494881865... [Read more]

divadiow 16 Jun 2024 11:14

Interesting to see an RTL8720CF in use. I wonder if any Tuya devices on Ali have WBR2s, I don't think I have one. [Read more]

divadiow 20 Dec 2024 07:21

https://www.elektroda.com/rtvforum/topic4093142.html - RTL8720CF development underway [Read more]

p.kaczmarek2 04 Jan 2025 10:56

Now supported: WBR2, WBR3, WBRU, W701-VA2-CG pinout, datasheet, flashing for Home Assistant [Read more]

FAQ

TL;DR: 10 A MaxCom SHSB111W10 buyers need this FAQ because the breaker used a WBR2/W701H WiFi module; the key warning was "there is no open software" for it, though later WBR2 support was announced. [#20589120] Why it matters: choosing the wrong Tuya switch can block Tasmota, Cloudcutter, and local Home Assistant control.

Option	Chip/module noted	Cloud-free path in thread	Cost/effort signal
MaxCom SHSB111W10	WBR2 / W701H	Initially unsupported; later WBR2 flashing support announced	About 40 PLN, but modification work
ESP-02S replacement	ESP module	Tasmota possible after module swap	“A dozen” PLN extra module cost
Original Sonoff Basic	ESP-based alternative implied	Better Tasmota choice	Not expensive, less complication
Qiachip smart switch	BK7231N	OpenBeken upload path	Suggested ready alternative

Key insight: The SHSB111W10 was not a simple Sonoff clone for Tasmota users. Its WBR2/W701H module changed the firmware path, so hardware identification mattered before purchase.

Quick Facts

The SHSB111W10 was reported as cheap, around 40 PLN, but its WBR2/W701H module prevented a straightforward open-firmware install at the time. [#20589120]
Internal power and switching parts included a 5 V relay, fuse, varistor, input filter, BP2905 supply circuit, and AMS1117-3.3V LDO regulator. [#20589120]
The WBR2 module was described with 256 KB SRAM and 2 MB Flash, using a KM4-core microcontroller. [#20589120]
The WBR2 pin table listed 11 pins, including 3V3, GND, EN, UART0_RXD on A13, and UART0_TXD on A14. [#20589120]
By 4 January 2025, later forum information announced support for WBR2, WBR3, WBRU, and W701-VA2-CG flashing for Home Assistant use. [#21376233]

What WiFi chip is inside the MaxCom Smart Breaker SHSB111W10 and why was it considered unsupported in the thread?

The MaxCom SHSB111W10 contains a WBR2 module with a W701H WiFi chip. The author considered it unsupported on 21 May 2023 because no open software was available for that chip at that moment. The module was listed with a KM4-core microcontroller, 256 KB SRAM, and 2 MB Flash. That blocked a direct Tasmota-style conversion without hardware changes. [#20589120]

What is the WBR2 or W701H module used in Tuya smart devices?

The WBR2 or W701H is the WiFi module found inside this Tuya-based smart breaker. "WBR2/W701H is a Tuya WiFi module that provides wireless control for smart devices, using a KM4-core microcontroller, 256 KB SRAM, and 2 MB Flash in this thread’s SHSB111W10 example." It appeared as the key barrier to open firmware in 2023. [#20589120]

How can the WBR2 module in a MaxCom SHSB111W10 be replaced with an ESP-02S or TYWE2S-compatible module?

Replace the WBR2 by desoldering it and fitting a pin-compatible ESP module. The thread describes this as possible because the WBR2 outputs match TYWE2S.

Open the clipped enclosure and expose the PCB.
Desolder the WBR2 module from its 11-pin footprint.
Solder in ESP-02S or a compatible TYWE2S-format module, then flash Tasmota. The author warned this is unlikely to be financially worthwhile. [#20589120]

Which ESP-based modules are pin-compatible with WBR2, WB2S, WR2, TYWE2S, and CB2S?

ESP-02S was named as an ESP-based replacement compatible with the WBR2-style footprint. The thread also says this popular module format matches CB2S, FL_M99_V1, TYWE2S, TYZS6, TW-02, WR2, WB2, WBR2, WR2E, WB2S, WA2, and XT-BL02. The practical point is physical pin compatibility, not guaranteed firmware compatibility across every chip. [#20589120]

Why did the author recommend buying an original Sonoff Basic instead of modifying the MaxCom SHSB111W10?

The author recommended an original Sonoff Basic because it avoided the WBR2 conversion work. The SHSB111W10 cost about 40 PLN, but an ESP-02S replacement added extra parts and soldering. The author summarized the economics clearly: buy the original Sonoff because it is not expensive either. That made the chip swap poor value. [#20589120]

MaxCom SHSB111W10 vs Sonoff BasicR2 — which is better for Tasmota or cloud-free firmware?

Sonoff BasicR2 is the better direct choice for Tasmota in this thread’s comparison. The MaxCom SHSB111W10 used WBR2/W701H hardware, so it was not a simple ESP-based Tasmota target in May 2023. A South African user later noted the Tuya device and original Sonoff were sold at the same price there. That made buying Tuya for a chip replacement financially unattractive. [#21119985]

What is Tasmota and why would users want to install it on a Tuya smart switch?

Tasmota is the firmware target mentioned for ESP-based replacement modules in this smart switch. "Tasmota is open firmware that users install on ESP-based smart devices, replacing vendor cloud behavior with local control when the hardware and pinout allow flashing." In the SHSB111W10, the user would need an ESP-compatible module such as ESP-02S before uploading it. [#20589120]

What is OpenBeken and how does it compare with Tasmota for BK7231N-based smart switches?

OpenBeken is the firmware path recommended for BK7231N-based smart switches. "OpenBeken is open firmware for non-ESP Tuya devices, used here as the suggested route for BK7231N hardware when Tasmota’s ESP-focused path does not fit." The author named a Qiachip smart switch on BK7231N as an alternative where OpenBeken can be uploaded. [#20589120]

What is Tuya Cloudcutter and why might it fail on devices using the W701H or RTL8720CF chip?

Tuya Cloudcutter is the tool a user tried before opening an Ineox LZWW-3 power strip. "Tuya Cloudcutter is a Tuya conversion tool that attempts firmware access without disassembly, but its success depends on supported device hardware and firmware." It failed on the strip, and inspection revealed W701H on an unmarked module. That created a replacement-identification problem. [#20846308]

What internal components were found inside the MaxCom SHSB111W10 smart breaker?

The SHSB111W10 contained a 5 V 005DC-HS QYT73 relay, fuse, varistor, input filter, BP2905 supply circuit, and AMS1117-3.3V LDO regulator. The PCB also carried the WBR2/W701H WiFi module. The enclosure used snap clips, and the screw terminals had protective covers. These details came from the teardown photos and board inspection. [#20589120]

How do I identify whether a Tuya smart switch uses WBR2, W701H, RTL8720CF, BK7231N, or ESP hardware?

Identify the hardware by opening the device and reading the WiFi module or chip markings. In this thread, WBR2 and W701H were visible inside the SHSB111W10 after opening the clipped case. Another user found W701H only after Cloudcutter failed on an Ineox LZWW-3 strip. An edge case is an unmarked module, which makes replacement choice unclear. [#20846308]

What should I check before buying a cheap Tuya smart switch if I want Home Assistant or local control support?

Check the WiFi module family before buying, not only the price or Tuya branding. A 40 PLN SHSB111W10 looked like a Sonoff-style switch, but it used WBR2/W701H instead of ESP hardware. For local control, look for known ESP, BK7231N, or later supported WBR2 paths. Otherwise, you may need soldering or another device. [#20589120]

Where should English-language questions about Elektroda Tuya device teardowns be posted?

English-language questions can be asked by considering the English Elektroda forum when the topic needs English discussion. A South African user asked on 15 June 2024 whether to post in English or create a new topic on the English forum. The thread later linked English-language development and support topics for RTL8720CF and WBR2-related work. [#21119985]

Which other devices were reported to contain the W701H chip, such as the Ineox LZWW-3 power strip?

An Ineox LZWW-3 power strip was reported to contain the W701H chip. The user tried Cloudcutter first, opened the strip after failure, and found W701H on an unmarked module. Another post reported the same smart-switch PCB and plastic cover sold in South Africa by Communica under different packaging. [#20846308]

What changed when WBR2, WBR3, WBRU, and W701-VA2-CG support for flashing and Home Assistant was later announced?

The status changed from unsupported to supported for WBR2-related flashing work. On 4 January 2025, a later post announced support for WBR2, WBR3, WBRU, and W701-VA2-CG pinout, datasheet, flashing, and Home Assistant use. That changed the original 2023 warning, where no open software was available for SHSB111W10’s WBR2/W701H module. [#21376233]

Summary generated by AI based on the discussion content.