I've bought a wall switch from Manhot Store in aliexpress with 4 "clicky" buttons.
AliExpress link: https://www.aliexpress.com/item/1005005901971631.html
The device is listed as a Zigbee Smart switch, but it's actually a WiFi switch!! with a CB3S chip inside.
Now the fun part!
Regarding functionality, when a button is pressed, the corresponding relay is triggered.
The button has a light that shows whether the relay is open or closed - it will show up as orange when the relay is ON and blue when the relay is OFF.
The device is powered by a CB3S chip, although not all of its pins are soldered on the PCB. Upon checking the datasheet for the MCU, we can determine the required pins to flash the device:
Datasheet: https://developer.tuya.com/en/docs/iot/cb3s?id=Kai94mec0s076
Soldered a small wire to the CEN pin to put the device into bootloader mode in order to flash a new firmware.
I was able to flash OpenBK using the new BK7231GuiFlashTool and the OpenBK7231N_QIO_1.17.308.bin firmware under windows, but no luck using the flash tool under linux (ubuntu).
I've attached the original .json device template.
This is the actual OpenBK pin configuration of the module.
Now only the orange led turn on when the relay is on, but the blue light doesn't work. it's fine...
AliExpress link: https://www.aliexpress.com/item/1005005901971631.html


The device is listed as a Zigbee Smart switch, but it's actually a WiFi switch!! with a CB3S chip inside.



Now the fun part!






Regarding functionality, when a button is pressed, the corresponding relay is triggered.
The button has a light that shows whether the relay is open or closed - it will show up as orange when the relay is ON and blue when the relay is OFF.
The device is powered by a CB3S chip, although not all of its pins are soldered on the PCB. Upon checking the datasheet for the MCU, we can determine the required pins to flash the device:
Datasheet: https://developer.tuya.com/en/docs/iot/cb3s?id=Kai94mec0s076
Soldered a small wire to the CEN pin to put the device into bootloader mode in order to flash a new firmware.
Pin Name | Pin Number |
CEN | 3 |
VCC | 8 |
GND | 9 |
RX1 | 15 |
TX1 | 16 |




I was able to flash OpenBK using the new BK7231GuiFlashTool and the OpenBK7231N_QIO_1.17.308.bin firmware under windows, but no luck using the flash tool under linux (ubuntu).
I've attached the original .json device template.
This is the actual OpenBK pin configuration of the module.
Pin | Type | Channel | P6 | WifiLED_n | - | P7 | Relay | 4 | P8 | Relay | 3 | P9 | Relay | 2 | P10 | Button | 4 | P14 | Relay | 1 | P23 | Button | 3 | P24 | Button | 2 | P26 | Button | 1 |
Now only the orange led turn on when the relay is on, but the blue light doesn't work. it's fine...


Cool? Ranking DIY