[BK7231N] Tuya Smart Power Strip Review: 4AC + 4USB Ports, AliExpress, YX-B3S1-VER00 PCB

VinceTheFox 16 Jun 2023 22:09 4 2844 Cool? (+2)

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TL;DR

A Tuya Wi‑Fi smart power strip from AliExpress with 4 AC outlets and 4 USB ports was opened and tested for local flashing.
The JSON config targets model XS-A26 on a CB3S board with a BK7231N chip.
The strip is rated AC100-240V, 16A, 3450W, with 3.1A USB power and a 1.5m power line.
Programming worked by briefly unplugging VCC to enter mode; CEN was not found, and an external 3.3V supply caused problems.
After flashing and configuration, the strip worked perfectly.

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Hi,
I'd like to share the results of this device from AliExpress.

I took elements from similar topics, as it has the same housing as this one, and a chip very similar to this one.

For dissassembing, the 6 pads on the back can be easily removed, giving access to 6 triangle screws:

The chip is a BK7231N on a small PCB with indication YX-B3S1-VER00

I have not tried programming the chip while still soldered to main PCB. Instead I have unsoldered it and used the pinout below:

I have not been able to find where is the CEN pin, I tried the 2 pins at the opposite of VCC and GND but it didn't work. On the other hand, unplugging VCC pin for a short time did the job to put the chip in programming mode.
Initially I also used a separate 3.3V power source instead of my cheap USB to TTL adaptor to power the chip, but for unknown reasons this option brought more problems than expected, as I was not able to put the chip in programming mode with this external power source.
Nevertheless using only the power source from the USB to TTL device (using 3.3V of course) was sufficient and appropriate in my case.

The device was detected by bk7231flasher v1.1.0b as:

Device configuration, as extracted from Tuya: 
- Relay (channel 3) on P14
- Relay (channel 4) on P9
- Pair/Toggle All Pin on P26
- WiFi LED on P23
- Relay (channel 2) on P8
- Relay (channel 5) on P24
- Relay (channel 1) on P7
Device seems to be using CB3S module, which is using BK7231N.
And the Tuya section starts, as usual, at 2023424

Now it works perfectly. Thanks to the community!

Edit - Here's the json config I used:

{
  "vendor": "Tuya",
  "bDetailed": "0",
  "name": "Wi-Fi Smart Power Strip",
  "model": "XS-A26",
  "chip": "BK7231N",
  "board": "CB3S",
  "flags": "1024",
  "keywords": [
    "Smart Power Strip",
    "USB Power Supply",
    "4 Gang",
    "Power line size: 1.5m",
    "Input voltage: AC100-240V 50/60Hz",
    "Rated current: 16A",
    "Rated power: 3450W",
    "USB rated power: 3.1A",
    "WIFI: 2.4GHz 802.11b/g/n",
    "Long* wide* high: 229*89*41mm"
  ],
  "pins": {
    "7": "Rel;1",
    "8": "Rel;2",
    "9": "Rel;4",
    "14": "Rel;3",
    "23": "WifiLED_n;0",
    "24": "Rel;5",
    "26": "Btn_Tgl_All;0"
  },
  "command": "",
  "image": "https://obrazki.elektroda.pl/9705431600_1686945840.jpg",
  "wiki": "https://www.elektroda.com/rtvforum/topic3984262.html"
}

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VinceTheFox wrote 1 posts with rating 2 , helped 1 times. Been with us since 2023 year.

Comments

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p.kaczmarek2 20 Jun 2023 12:31

Very nice review. Isn't that module a Beken version of LM2? Pinout seems to be matching. https://obrazki.elektroda.pl/9274397200_1687257035_thumb.jpg Btw, you can script that device so single... [Read more]

divadiow 31 Oct 2024 21:01

https://github.com/OpenBekenIOT/webapp/pull/157/commits/3723c3d67edb5bcaef1e3a0ccdd8325cc1bc4098 [Read more]

p.kaczmarek2 01 Nov 2024 10:09

Oh, so it wasn't on our devices list already? I must have missed that! Thank you, added. It seems we're reaching 650 devices now. [Read more]

yvesdm3000 14 Oct 2025 12:37

I could not get this chip into programming mode by power-cycling it. Touching the round pad at the back that is closest to the solder pads with ground did the trick for me. So I suppose that is the CEN... [Read more]

FAQ

TL;DR: The Tuya XS-A26 has 4 AC outlets + 4 USB ports; expert takeaway: "Now it works perfectly." This FAQ helps OpenBeken users disassemble, flash, and configure the BK7231N/CB3S YX-B3S1 power strip from AliExpress. [#20620024] Why it matters: This device combines mains-voltage switching, USB power, and BK7231N firmware modding, so the correct pin map and flashing method reduce bricking and safety risk.

Alternative	Specific value	Practical result
YX-B3S1-VER00	CEN not found in the first report	Short VCC disconnect entered programming mode
YX-B3S1-VER01	Round rear pad near solder pads	Grounding that pad entered programming mode
USB-to-TTL 3.3 V power	Worked in the first report	Enough for flashing the unsoldered module
Separate 3.3 V supply	Caused programming-mode issues	More trouble than USB-to-TTL power

Key insight: Treat the YX-B3S1 board as a BK7231N CB3S-style module, then use the extracted Tuya pin map. If CEN is unclear, use controlled VCC cycling or the identified reset pad on VER01.

Quick Facts

Model used for the template: Tuya Wi-Fi Smart Power Strip XS-A26, with BK7231N chip and CB3S board. [#20620024]
Electrical listing in the shared JSON: AC100–240 V, 50/60 Hz, 16 A, 3450 W, and USB 3.1 A. [#20620024]
Physical and wireless specs listed: 1.5 m power cable, 229 × 89 × 41 mm body, and 2.4 GHz 802.11b/g/n Wi-Fi. [#20620024]
Access requires removing 6 rear pads and 6 triangle screws, which exposes the internal PCB assembly. [#20620024]
Device-list maintenance continued after the review; by 2024-11-01, the maintainer said the list was reaching 650 devices. [#21284909]

How do I disassemble the Tuya XS-A26 4AC + 4USB smart power strip with the YX-B3S1 PCB?

Remove the 6 rear pads, then undo the 6 triangle screws under them.

Unplug the strip from AC mains.
Peel off the 6 pads on the back.
Remove the 6 triangle screws and open the housing.

The reviewed unit used a small PCB marked YX-B3S1-VER00 with a BK7231N chip inside. [#20620024]

What pin configuration should I use for OpenBeken on the Tuya XS-A26 smart power strip with a BK7231N CB3S module?

Use relays on P7, P8, P14, P9, and P24, with button P26 and Wi-Fi LED P23. OpenBeken mapping: P7=Rel;1, P8=Rel;2, P14=Rel;3, P9=Rel;4, P24=Rel;5, P26=Btn_Tgl_All;0, P23=WifiLED_n;0. The shared template names the device Wi-Fi Smart Power Strip, model XS-A26, chip BK7231N, board CB3S. [#20620024]

How can I put the BK7231N chip on the YX-B3S1-VER00 board into programming mode if I cannot find the CEN pin?

Briefly disconnect VCC, then reconnect it while using bk7231flasher. The original flasher attempt could not identify CEN on YX-B3S1-VER00. Two opposite pins from VCC and GND did not work. A short VCC unplug did enter programming mode. Powering the chip only from the USB-to-TTL adapter at 3.3 V worked in that case. [#20620024]

Why might power-cycling VCC work better than using the CEN pin when flashing a BK7231N module?

Power-cycling VCC works when the reset or CEN pad is unknown or inaccessible. On the YX-B3S1-VER00 board, the first report could not locate a working CEN pin. Disconnecting VCC briefly forced the chip into the boot state needed for flashing. This avoided probing unconfirmed pads on a small module. [#20620024]

Where is the likely CEN pin or reset pad on the YX-B3S1-VER01 PCB used in this Tuya smart power strip?

The likely CEN pad is the round rear pad closest to the solder pads. A later YX-B3S1-VER01 board would not enter programming mode by power-cycling. Grounding that round rear pad entered programming mode. The same report found no noticeable functional difference from YX-B3S1-VER00. [#21719931]

What is a BK7231N chip and why is it used in Tuya smart power strips?

BK7231N is the Wi-Fi microcontroller used to run the Tuya power strip logic. "BK7231N is a wireless IoT chip that controls Wi-Fi connectivity and GPIO switching, commonly appearing on Tuya modules such as CB3S in this thread's smart power strip." The reviewed unit exposed 5 relay outputs, one button input, and one Wi-Fi LED through BK7231N pins. [#20620024]

What is a CB3S module and how does it relate to the BK7231N in Tuya devices?

CB3S is the module format detected for the BK7231N board in this device. "CB3S is a compact Tuya Wi-Fi module that carries a BK7231N chip, providing the soldered module interface between the main PCB and firmware-controlled pins." bk7231flasher identified the device as using CB3S, and the Tuya section started at 2023424. [#20620024]

What is the YX-B3S1-VER00 or YX-B3S1-VER01 PCB found inside AliExpress Tuya power strips?

YX-B3S1 is the small internal Wi-Fi module PCB used in this Tuya power strip. The first reviewed board carried the marking YX-B3S1-VER00. A later unit carried YX-B3S1-VER01 and showed no noticeable difference in use. Both reports concern AliExpress Tuya power strips with BK7231N-based firmware work. [#21719931]

How do I flash OpenBeken onto a BK7231N smart power strip using bk7231flasher and a USB-to-TTL adapter?

Unsolder the module, wire UART and 3.3 V, then trigger programming mode.

Remove the module from the main PCB before flashing.
Power it from the USB-to-TTL adapter at 3.3 V.
Start bk7231flasher, then briefly cycle VCC if CEN is unknown.

bk7231flasher v1.1.0b extracted the Tuya relay, button, and LED configuration from the reviewed strip. [#20620024]

Why would an external 3.3V power supply cause problems when flashing a BK7231N compared with powering it from a USB-to-TTL adapter?

The external 3.3 V supply caused boot-mode entry failures in the reported setup. The first flashing attempt used a separate 3.3 V power source. That setup created more problems and failed to enter programming mode reliably. The USB-to-TTL adapter's own 3.3 V output was sufficient for the unsoldered chip. [#20620024]

BK7231N CB3S vs Beken LM2-style module: what are the pinout similarities and differences?

The CB3S pinout appeared to match a Beken LM2-style layout closely. A maintainer asked whether the module was a Beken version of LM2, because the pinout seemed to match. The thread did not list electrical differences. Treat this as a pinout comparison, not proof of full module interchangeability. [#20624273]

How can I script OpenBeken so one button on a Tuya power strip toggles different relays with single, double, or multiple clicks?

Use OpenBeken scripting so click count maps to relay number. The maintainer stated that one script can make a single click toggle the first relay, a double click toggle the second relay, and so on. This suits the strip because the Tuya map has Btn_Tgl_All on P26 and relays on 5 pins. [#20624273]

What do the relay pins P7, P8, P9, P14, and P24 control on the Tuya XS-A26 4-gang power strip?

They control relay channels 1, 2, 4, 3, and 5 respectively. The extracted Tuya configuration maps P7 to relay 1, P8 to relay 2, P14 to relay 3, P9 to relay 4, and P24 to relay 5. The fifth relay likely covers the USB or master switching path in this 4AC + 4USB device. [#20620024]

How should I safely work on or modify a 16A 3450W Tuya smart power strip with AC mains inside?

Work only with the strip unplugged, because it contains AC mains circuitry. The shared device specs list AC100–240 V, 50/60 Hz, 16 A, and 3450 W. Those values can cause lethal shock or fire if mishandled. Do not power the opened main PCB while touching it. Flash only the removed low-voltage module when possible. [#20620024]

Where can I find device templates or add a new Tuya BK7231N smart power strip to the OpenBeken devices list?

Use the OpenBeken device list and submit the template through the project workflow. A later contributor linked a webapp pull request for this device entry on 2024-10-31. The maintainer replied on 2024-11-01 that the device was added. He also noted the list was reaching about 650 devices. [#21284909]

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