Module name: Moes Smart Switch Module MS-104
Protocol: WiFi 2,4GHz
Input Voltage: 90 - 250V AC 50/60Hz
Max Current: 10A
Wifi module: Tuya CB2S (BK7231N) datasheet
This is the 1 gang vesion of the module there is also a 2 gang version available (obviously with the same PCB based on tear-down).
Bought it on aliexpress from MOES Online store. It has also Zigbee, Zigbee+RF, WiFi+RF versions.
4 gang version has different internals, see tear-down in other topic: Link Flashed latest release with python flasher: hid_download_py
Pictures of the module:
Tear-down of the module:
Pin26: Buzzer (works as PWM)
Edit: One easy way I have found to put CB2S into programming mode to put a solder blob between CSN pad and the cooling pad next to it to ground it:
Well I haven't tried it with Tuya fw. My guess is that it's the same as the dimmer version with the Tuya MCU: Link Perhaps the idea was to notify connection issues by sound when the module is installed in a wall box behind the switch.
Also this one doesn't have any LEDs, they have added the buzzer instead. In the linked thread it's mentioned that the beeps correspond the LED blinks on that module.
I have created a PIR motion sensor mod of this sensor. See pictures below.
Used the place of the second relay for this. Checked the PCB and found out that one of the holes for the relay has 5V. There is also a ground pad nearby, and the other whole is not connected anywhere, so that became the PIR sensor output to easily get to the back of the PCB to connect to the CB2S.
Used this sensor from Ali: aliexpress.com