[WBR2/W701] Unsupported MaxCom Smart Breaker SHSB111W10

.
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:
.
From the outside it resembles the Sonoff classic, but there is no ESP inside.
.
This is what it looks like in practice:
.
.
.
.

.
.
Instructions, including a description of the pairing:
.
Screw terminal protectors:
.


Interior of SHSB111W10 .
The casing is held in place by snaps.
.
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:
. .
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:
.
Apart from that, there is also an AMS1117-3.3V, LDO regulator.
Well, and a WiFi module:
.
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"> .
.
The ESP-02S can be purchased for a dozen gold:
.
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.