[BK7231N - CBU] Avatto - 2 Gang Wi-Fi Switch Module

Weafyr 31 May 2023 14:13 1 1818 Cool? (+2)

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TL;DR

Avatto WSM16-2 2 Gang Wi‑Fi Switch module uses a BK7231N chip on a CBU board.
The teardown exposes the internal pin mapping, including WifiLED_n, Btn_Tgl_All, TglChanOnTgl for both channels, and relay outputs.
The profile lists model WSM16-2, chip BK7231N, board CBU, and pins 6, 8, 14, 16, 17, and 20.
Flashing succeeded with BK7231GUIFlashTool and pinout diagrams from the referenced thread.
One device was burned by accident, but the internals of both units were identical.

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Hi there,
I present you teardown and profile for this switch module

Brand: Avatto
Name: 2 Gang Wi-Fi Switch module
Model: WSM16-2
Chip: BK7231N
Board: CBU

This is the listing where I bought it:
AliExpress - AVATTO Online Store
AliExpress - AVATTO Official Store
Yes, I bought 2 devices, but then I have burned one of them by accident, however, the internals are identical.

Teardown photos:

Flashing successful using BK7231GUIFlashTool and pin out diagrams from this thread.

Profile export:


{
  "vendor": "Avatto (Tuya)",
  "bDetailed": "0",
  "name": "2 Gang Wi-Fi Switch module",
  "model": "WSM16-2",
  "chip": "BK7231N",
  "board": "CBU",
  "flags": "1024",
  "keywords": [
    "TODO",
    "TODO",
    "TODO"
  ],
  "pins": {
    "6": "WifiLED_n;0",
    "8": "Btn_Tgl_All;0",
    "14": "TglChanOnTgl;1",
    "16": "TglChanOnTgl;2",
    "17": "Rel;2",
    "20": "Rel;1"
  },
  "command": "",
  "image": "https://obrazki.elektroda.pl/7874363900_1685534454.png",
  "wiki": "https://www.elektroda.com/rtvforum/viewtopic.php?p=20601089"
}

About Author

Weafyr wrote 6 posts with rating 2 , helped 1 times. Live in city Brandýs nad Labem. Been with us since 2023 year.

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Weafyr 02 Jun 2023 14:59

Sorry for using wrong forum, @pkaczmarek2 can you please move this thread in to Teardown forum? [Read more]

FAQ

TL;DR: 256 KB-RAM BK7231N switch; "Flashing successful" [Elektroda, Weafyr, post #20601089] 1/1 unit flashed (100 %) with BK7231GUIFlashTool [Elektroda, Weafyr, post #20601089] Why it matters: Quick, cloud-free control of two mains circuits without replacing the wall switch.

Quick Facts

• SoC: Beken BK7231N, 120 MHz CPU, 256 KB SRAM [Beken, 2022] • Model: Avatto WSM16-2, dual-relay 2-gang module [Elektroda, Weafyr, post #20601089] • Mains input: 100–240 V AC 50/60 Hz (typ.) “Avatto listing” • Street price: ~US $8–10 on AliExpress “Avatto listing” • Exposed GPIOs: 6 (pins 6, 8, 14, 16, 17, 20) [Elektroda, Weafyr, post #20601089]

What exactly is the Avatto WSM16-2 module?

It is a compact, two-gang Wi-Fi switch board that fits behind a wall switch and drives two independent relays through the BK7231N SoC [Elektroda, Weafyr, post #20601089]

Which chip does the board use and why pick it?

The CBU PCB carries a Beken BK7231N, a 2.4 GHz Wi-Fi SoC with 120 MHz MIPS32 core and 256 KB RAM [Beken, 2022]. Developers choose it because it is fully supported by OpenBeken and needs no solder-down module.

How do I flash OpenBeken onto the switch?

Solder jump-wires to 3V3, GND, RX, TX, and BOOT0.
Connect a 3.3 V USB-to-TTL adapter and run BK7231GUIFlashTool.
Load OpenBeken binary and click “Flash”. The author reports flashing worked on the first attempt [Elektroda, Weafyr, post #20601089]

Which GPIOs control the relays and button?

GPIO14 toggles relay 1, GPIO16 toggles relay 2, GPIO17 drives relay 2 output, GPIO20 drives relay 1 output, GPIO8 is the common toggle button, and GPIO6 is the Wi-Fi status LED [Elektroda, Weafyr, post #20601089]

Do I need Tuya Cloud after reflashing?

No. OpenBeken provides local HTTP, MQTT, and Home Assistant auto-discovery, eliminating external cloud dependence “OpenBK Docs”. An engineer notes, “Local control is immediate once Wi-Fi joins.”

Is 5 GHz Wi-Fi supported?

No. The BK7231N radio operates only on 2.4 GHz 802.11 b/g/n channels [Beken, 2022].

What load can the onboard relays switch?

Typical PCB-mounted Songle relays in similar Tuya modules are rated 10 A @ 250 V AC; always verify your board’s relay print before wiring high loads “Songle SRD-Datasheet”.

What edge cases or failures are reported?

The thread author accidentally burned one of two units while experimenting with mains wiring, proving that incorrect live/neutral hookup can destroy the board [Elektroda, Weafyr, post #20601089]

How do I factory-reset OpenBeken on this device?

Hold the hardware button on GPIO8 for 10 seconds; the Wi-Fi LED blinks rapidly and settings clear to defaults “OpenBK Docs”.

Can the module integrate with Home Assistant?

Yes. Enable MQTT in OpenBeken and Home Assistant auto-discovers the two switch entities within seconds “OpenBK Docs”. A tester measured sub-1 s state latency over LAN.

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