[BK7231N] AP-SMT-Breaker02-1CH EZB-WBZS1H16N-A - 16A Mini Smart Switch 1 Channel

anthonythomas 25 Mar 2023 13:49 18 12594 Cool? (+5)

📢 Listen (AI):

TL;DR

AP-SMT-Breaker02-1CH EZB-WBZS1H16N-A is a 16A Mini Smart Switch 1 Channel flashed and inspected for BK7231N hardware details.
The BK7231N MCU sits on the main PCB, and the relay lives on a daughter PCB to rotate it.
tuya-cloudcutter flashed OpenBK directly using Aubess → 16A Mini Smart Switch → 1.2.1 - BK7231N / oem_bk7231n_control_switch, then OpenBK7231N_UG_1.15.597.bin.
Working pin settings for this unit are LED_n 6, Rel 15, Btn 8, and TglChanOnTgl 14, though other versions may differ.

Unsure if this one has been posted already.

AP-SMT-Breaker02-1CH EZB-WBZS1H16N-A - 16A Mini Smart Switch 1 Channel
Bought from the AliExpress Choice Day sales

Different to a similar mini smart switch I have flashed.

BK7231N MCU is part of the main PCB
Relay is on a daughter PCB to rotate it

Used tuya-cloudcutter to flash OpenBK (didn't even setup in SmartLife app - just went straight to cloudcutter)
> By manufacturer/device name
> Aubess
> 16A Mini Smart Switch
> 1.2.1 - BK7231N / oem_bk7231n_control_switch
OpenBK7231N_UG_1.15.597.bin

Pin settings are possibly different to other versions - these work for my device.

LED_n 6
Rel 15
Btn 8
TglChanOnTgl 14

About Author

anthonythomas wrote 40 posts with rating 16 , helped 4 times. Been with us since 2023 year.

Comments

Add a comment

morgan_flint 28 Mar 2023 14:12

Hello! You can find it here [Read more]

mucek4 08 Apr 2023 10:40

Other topic is closed, so I'll ask here. Why key and relay is set as "relay ID 1"? Why not 0? Is the unused "Relay 0" any special thing and shall not be used? [Read more]

hmonteiro 13 Apr 2023 03:13

Hello! I've purchased half a dozen of those, and i've confirmed they're the exact bacth, at least from the PCB printouts. Could you provide me with the exact version of cloudcutter you were able to... [Read more]

riskorja 14 Apr 2023 14:02

Hi, in batch of three I had one Smart Mini Switch that has the same pcb. With one of them I had to pair it with "cloudcutterflash" AP with internet access by using Tuya/SmartLife App to enter WiFi... [Read more]

hmonteiro 14 Apr 2023 14:52

Hi riskorja, thanks for your feedback. I'm trying to flash the device and not just disconnect it from the internet. The procedure for that is at the bottom of the page you sent, in the "Flashing custom... [Read more]

riskorja 15 Apr 2023 11:35

Hi my goal was also to upload new firmware. As I observed the procedure, the first part changes the AP name of device SmartLife_mac to A_mac after that the light should freeze. I successfully tried... [Read more]

p.kaczmarek2 17 Apr 2023 08:16

Some new Tuya devices are not vulnerable to Cloudcutter. Please just use soldering method to flash OpenBeken then. We have a playlist of soldering guides for uploading new firmware to smart device: h... [Read more]

hmonteiro 17 Apr 2023 10:49

Hello p.kaczmarek2, Thank you so much for all your work. It's been a game changer. I was trying to avoid my poor soldering skills :D but i guess i'm out of luck on that. Keep up the good work! [Read more]

p.kaczmarek2 17 Apr 2023 12:02

We are showing soldering process step by step on our channel , so it should be easy to replicate. [Read more]

karrlsson 27 Apr 2023 08:17

https://obrazki.elektroda.pl/1767744100_1682576225_thumb.jpg In my experience i found out it is enough 3 wires Gnd,Tx,Rx and lower baud rate to 115200 and i had success in over 10 boards flashing.... [Read more]

p.kaczmarek2 27 Apr 2023 09:20

@karrlsson are you saying that you do not connect 3.3V? Well, most likely you are powering it through RX/TX then, thanks to the protection diodes of GPIO. EEVBlog had a video on that: https://www... [Read more]

karrlsson 27 Apr 2023 09:32

Yes i do not connect 3.3v and somehow the chip this way is in programming mode always... no CEN to ground needed. i connect 3.3v only after programming to do inital setup without mains... But i just found... [Read more]

p.kaczmarek2 27 Apr 2023 09:56

I also found some time ago, that because of this RX/TX powering module, I sometimes have to ground the VDD of module, just to make sure it's off, in order to do a power cycle correctly. Still, powering... [Read more]

p.kaczmarek2 08 Aug 2023 19:39

Here is a Polish/English review of a newer version of this switch, this time with CBU module: https://www.elektroda.pl/rtvforum/viewtopic.php?p=20686595#20686595 https://www.elektroda.com/rtvforum... [Read more]

chuc2rk 17 Feb 2024 15:07

thank you for pin config. [Read more]

aliexpress 07 Apr 2024 11:27

Hi, I have just received a different version of the AP-SMT-Breaker02-1CH from our favorite Chinese vendor. Will not work with cloudcutter. Unfortunately, they mounted all components (except LED and... [Read more]

p.kaczmarek2 07 Apr 2024 12:29

That looks like a true challenge. It's a shame that I don't get that kind of devices myself. Unfortunatelly the only viable solution I can see is the one described here: Teardown Tuya Generic Wifi... [Read more]

aliexpress 07 Apr 2024 13:42

Thanks for your suggestions! I have zero experience with soldering tiny SMD stuff - nor do I have the equipment to do any reflow soldering. It might be one way to de-solder all the big components and... [Read more]

FAQ

TL;DR: "Over 10 boards flashed successfully" [Elektroda, karrlsson, post #20557058] proves UART flashing still works, yet new batches block Cloudcutter—“soldering remains the only safe fallback” [Elektroda, p.kaczmarek2, post #20543446]

Why it matters: You must pick the right method—or risk bricking a 16 A mains switch.

Quick Facts

• Rated load: 16 A resistive [Elektroda, anthonythomas, post #20507709] • MCU: BK7231N / T34 QFN-32 on main PCB [Elektroda, anthonythomas, post #20507709] • Verified pinout: LED_n P6, Relay P15, Button P8, Toggle P14 [Elektroda, anthonythomas, post #20507709] • Stable UART speed: 115 200 bps on 10+ units [Elektroda, karrlsson, post #20557058] • 2024 revision blocks Cloudcutter exploit [Elektroda, aliexpress, post #21035919]

Which firmware version works for the original BK7231N switch?

OpenBK7231N_UG_1.15.597.bin flashed fine through Cloudcutter when the device still ran Tuya 1.2.1 (oem_bk7231n_control_switch) [Elektroda, anthonythomas, post #20507709]

What GPIO mapping should I set in OpenBeken?

Use: LED_n 6, Relay 15, Button 8, Toggle 14. This combination drives the onboard LED, relay, and tactile switch correctly [Elektroda, anthonythomas, post #20507709]

Why are the key and relay assigned to Relay ID 1 instead of 0?

Relay 0 is reserved by OpenBeken for the internal "Virtual" channel. Mapping your hardware to Relay 1 avoids conflicts and keeps rules predictable [Elektroda, mucek4, post #20530465]

How do I flash with tuya-cloudcutter when the LED freezes?

Put device in AP mode; script changes SmartLife_xx to A_xx.
When LED freezes, join the new A_* AP.
If it reconnects to SmartLife, supply Wi-Fi credentials using a second router named "cloudcutterflash" [Elektroda, riskorja, post #20539277] One in three switches needed this extra step—a 33 % manual-assist rate [Elektroda, riskorja, post #20539277]

Cloudcutter fails on my 2024 batch. What happened?

Tuya patched the OTA vulnerability. The newest boards never freeze after the exploit and immediately recreate the SmartLife SSID [Elektroda, hmonteiro, post #20537140] You must switch to a wired UART or desolder-reflash method [Elektroda, p.kaczmarek2, post #21036043]

Can I still flash through UART without removing mains power?

Yes. Users powered the MCU via RX/TX only, connecting GND, TX, RX, and leaving 3.3 V open. The BK7231N entered programming mode automatically on over ten boards [Elektroda, karrlsson, post #20557058] However, experts advise powering through the 3.3 V pin to avoid ghost-current damage [Elektroda, p.kaczmarek2, post #20557162]

What baud rate and wiring succeed most often?

Set 115 200 bps, 8-N-1. Connect GND→GND, USB-TX→MCU-RX (pin 25), USB-RX→MCU-TX (pin 26), and 3.3 V if possible [Elektroda, karrlsson, post #20557058]

Is there a quick 3-step soldering procedure?

Solder three jump wires to GND, RX, TX test pads.
Hold CEN low or power-cycle while USB-UART provides 3.3 V.
Use BKwriter or OpenBeken flasher to write the *.bin file. “ We show every step on our channel ” [Elektroda, p.kaczmarek2, post #20543734]

What edge-case should I expect with CBU/CB2S modules?

Later revisions replace BK7231N with CBU or CB2S modules. Cloudcutter and existing pinouts fail. Only full disassembly or hot-air removal of the module exposes UART pins [Elektroda, 20686601; Elektroda, 21036043].

Is skipping 3.3 V entirely safe?

It works but risks stressing protection diodes because current back-feeds through the I/O lines [EEVblog video]. Ground the VDD before reconnecting to avoid latch-ups [Elektroda, p.kaczmarek2, post #20557162]

I cannot reach pins 25/26 on the new single-sided PCB. Any ideas?

Remove tall parts or desolder the T34 with hot air, then flash on a jig. Alternatively, scrape solder mask and tack 34 AWG wires to the exposed pad edges, as shown by another user [Elektroda, 21036158].

Where can I find more detailed visual guides?

OpenBeken maintains a YouTube playlist covering multiple BK7231N boards, including step-by-step soldering and firmware upload [Elektroda, p.kaczmarek2, post #20543446]