[BK7231N/CB2S] SWP86-01OG energy measurement socket

p.kaczmarek2 05 Aug 2023 18:55 18 3915 Cool? (+3)

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TL;DR

The SWP86-01OG is a WiFi smart socket with onboard voltage, power, and current measurement.
Inside are a BL0937 metering IC with a shunt, a CB2S BK7231N module, a J3Y transistor, an AMS1117-3.3V regulator, and a BP2525 supply.
It was bought for PLN 65, and the outlet uses the schuko standard, which can create grounding compatibility issues with some plugs.
Firmware replacement uses soldered CB2S pins, BK7231GUIFlashTool, and OpenBeken; GPIO mapping and VoltageSet/CurrentSet/PowerSet calibration make it work locally with Home Assistant.
The power supply is a simple step-down, not a flyback design, so the socket has no galvanic isolation.

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Today I will present the interior and firmware change of an electrical socket that offers WiFi control and, additionally, measurement of voltage, power and current. I have already described "smart" products with energy measurement, but there was no socket in this style yet. Will I be able to free it from the cloud? What WiFi module is inside? Let's check.

Purchase SWP86-01OG
The product was bought on a Polish auction website for PLN 65:

The specific model name may not be available in the offer description, but it is available on the socket itself. There is also something else that catches the eye in this nest - after all, it is not typical for our country, but "schuko". This may cause some serious problems with grounding if, for example, we forget and connect a plug that is not compatible with it!
The product is available in two colors, white and black:

Dimensions as in the picture above, depth shown below:

Product packaging:

Contents of the set, is something missing?

Nothing could be further from the truth, the front panel is simply loose:

The socket itself with markings:

It is worth noting that the screws are also included in the set.

Interior of SWP86-01OG
First, unscrew all the small screws holding the front:

This allows you to free the front, we can see the cable on which the pairing/state change button and LED are connected:

We look inside:

You can immediately see BL0937 - the energy measurement system - along with a low-resistance resistor, a shunt on which the measurement is performed.

You can also see the legs from the soldered WiFi module (CB2S or WB2S?), the transistor code J3Y, which reliably switches the relay, and the AMS1117-3.3V LDO regulator:

Power is provided by BP2525:

It's just a simple step down, it's not even a flyback power supply, there is no galvanic separation... but no one is likely to push their fingers inside the socket.
Some additional photos:

Ok, unscrew the screws and take out the PCB:

There is a CB2S module, as I thought, BK7231N.
You can also see some input protection, a fuse resistor, a varistor, an anti-interference capacitor:

PCB from the bottom:

Firmware change
All you need to do is solder the CB2S (or WB2S) pins, the pins are in the network, everything in accordance with:
https://github.com/openshwprojects/BK7231GUIFlashTool
Flux, plus a little lead binder would make soldering better and you can easily get to it through four wires:

There remains the issue of GPIO. Here is the schedule:

And the template:

Ready. You still need to calibrate the energy measurement using the VoltageSet/CurrentSet/PowerSet commands, as in Tasmota , and then you can use this device 100% locally, without potential manufacturer surveillance, and connect it conveniently with Home Assistant.

Summary
This product is not as expensive as it may seem, especially since it is available on our national auction site, with the possibility of free smart delivery to a parcel locker. Energy measurement certainly increases its usefulness. It is also worth remembering that the button on the housing also allows you to control it, so in the event of a problem with WiFi, we are not completely cut off from control.
After changing the firmware, you can also script OpenBeken so that another product (e.g. a light switch) controls this socket locally, just add one line with the button event handler (e.g. double-click), sending an HTTP GET event with the POWER TOGGLE command to the IP of the socket . All without the use of the cloud and even without Home Assistant.
Details about firmware here:
https://github.com/openshwprojects/OpenBK7231T_App
And in the documentation section:
https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/README.md
Does any reader have this type of "smart" sockets at home?

About Author

p.kaczmarek2 wrote 14612 posts with rating 12629 , helped 655 times. Been with us since 2014 year.

Comments

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Jufo 06 Aug 2023 10:29

I definitely prefer schuko sockets, double grounding, no lock before turning the plug, and the plugs nowadays (I dare say it's probably 10 years old) are uni-schuko (operation with pin and schuko),... [Read more]

ro-x 09 Aug 2023 06:22

Can I ask for the exact dimensions of the socket front, including the depth measured from the front to the mounting plate? I wonder if it will be possible to fit them into a standard frame from another... [Read more]

Jacenko1981 10 Aug 2023 22:18

My friend from work bought 3 of these sockets. He installed it and it worked within 3-5 months. They failed one after the other. Strangely enough, they always failed when there was a power outage and he... [Read more]

p.kaczmarek2 11 Aug 2023 05:48

I'd love to dissect it. I once had a smart device with a capacitor that needed to be replaced: https://www.elektroda.pl/rtvforum/topic3898805.html As for the dimensions, unfortunately I can't... [Read more]

Jacenko1981 11 Aug 2023 10:43

I asked my friend about the sockets, two of them he must have thrown away, dot the third one, he should have it somewhere in the garage, although he doesn't know whether it was thrown into the trash... [Read more]

ro-x 11 Aug 2023 21:45

And I asked the Allegro seller. I'll let you know when I hear back. I don't know how important it is for others, but I have many serial frames from the developer, with 3, 4 or even 5 modules,... [Read more]

Jacenko1981 15 Aug 2023 17:45

I will add from recent information that my friend did not find the toy. He also admitted that he didn't look for anything special because of the renovation, the furniture had been brought into the... [Read more]

omniron 16 Nov 2023 16:15

My units seems a bit different than yours: https://obrazki.elektroda.pl/6015287300_1700146934.jpg https://obrazki.elektroda.pl/3007793700_1700146855.jpg https://obrazki.elektroda.pl/3373481400_1700146733.jpg I... [Read more]

p.kaczmarek2 16 Nov 2023 16:33

What WiFi module? CB2S? Desolder CB2S and then try: Alternatively with hid_download_py: https://www.youtube.com/watch?v=PKkiqDNFIx8 https://github.com/openshwprojects/OpenBK7231T_App https... [Read more]

omniron 17 Nov 2023 02:13

Yes, CB2S, but I simply cannot remove-solder these things, have to use OTA. [Read more]

omniron 30 Nov 2023 20:14

It's actually a TWB2S1-ZR (BK7231T). It has no power meter, and instead of using a 3.3V relay, they use a 5V AC/DC converter (same SZ2525C) and then a linear DC/DC converter for the 3.3V! attached the... [Read more]

p.kaczmarek2 24 Mar 2024 15:21

Most of the Tuya devices are nowadays patched. The serial flashing approach is more reliable. You can check out our Elektroda.com flashing guides playlist here: https://www.youtube.com/watch?v=L6d42IMGhHw&list=PLzbXEc2ebpH0CZDbczAXT94BuSGrd_GoM I... [Read more]

mbk_med 29 Sep 2024 22:45

hi posted an other variant with w600/tw-02 https://www.elektroda.com/rtvforum/viewtopic.php?p=21244273 [Read more]

mbk_med 17 Nov 2025 17:39

Hey, I recently bought a new socket using the CB2S chip, and after flashing it and setting up the pins, the physical button stopped working (it supposed to turn the relay on/off). I checked the “GPIO... [Read more]

p.kaczmarek2 17 Nov 2025 19:17

Have you tried Tuya Config Extraction? [Read more]

mbk_med 17 Nov 2025 20:23

Hello, yes, I tried it, but my file is not readable. I got an error when I opened it in BK7231Flasher. I tried with two files extracted from two sockets, and I got the same error. https://obrazki.... [Read more]

insmod 17 Nov 2025 20:29

Try with latest flasher [Read more]

mbk_med 17 Nov 2025 21:23

Thanks. With the latest version, v154, I got this. It seems it doesn’t contain any configuration. Is there a solution? https://obrazki.elektroda.pl/3570396900_1763410819_thumb.jpg [Read more]

FAQ

TL;DR: At PLN 65, this CB2S/BK7231N wall socket can be flashed for 100% local control, and the author’s verdict is clear: “Ready.” This FAQ helps OpenBeken users wire, map, calibrate, and troubleshoot SWP86-01OG variants, including non-metering revisions and button-mapping failures. [#20682308]

Why it matters: This thread shows that the same socket name can hide different boards, power supplies, and flashing paths, so correct identification matters before you solder or deploy.

Variant	Wi-Fi/module	Energy metering	Notable detail
SWP86-01OG	CB2S / BK7231N	Yes, BL0937	Thread includes full OpenBeken pin map
Similar unit shown later	TWB2S1-ZR / BK7231T	No	Uses 5 V AC/DC plus 3.3 V linear regulator
AVATTO N-WOT10-EU-W	Not detailed here	Not specified	Mentioned as a similar device under another model name
W600/TW-02 variant	W600/TW-02	Variant-dependent	Posted as another hardware revision

Key insight: Do not trust the product name alone. The thread documents at least one SWP86-01OG with BL0937 metering and another similar socket without any power-meter hardware, so board inspection comes first. [#20840579]

Quick Facts

The opening post states a purchase price of PLN 65 on a Polish auction site, while another user later reports a market range of PLN 50 to PLN 120 per unit. [#20689421]
The metering version uses CB2S with BK7231N, BL0937 for measurements, AMS1117-3.3V, and a BP2525 non-isolated step-down supply. [#20682308]
The published OpenBeken pin map assigns GPIO 6 button, 7 relay, 8 BL0937SEL, 10 WiFi LED, 24 CF, and 26 CF1. [#20682308]
One failure report covers 3 sockets that died after 3–5 months, reportedly after mains outages and generator use, while a simple plug-in meter kept working. [#20689421]

How do you flash the SWP86-01OG smart socket with OpenBeken using the CB2S BK7231N module and serial wiring?

Flash it by wiring directly to the CB2S pads and using a BK7231 serial tool. 1. Solder four wires to the CB2S pins shown in the linked flash-tool guide. 2. Use flux and a little leaded solder to make the joints easier. 3. Flash OpenBeken with BK7231GUIFlashTool, then load the socket template and calibrate metering. The author says the pins are available online and shows the board as CB2S with BK7231N. [#20682308]

What GPIO pin mapping and template settings are needed for the SWP86-01OG energy metering socket with BL0937?

Use the template published in the thread for the CB2S/BK7231N metering version. Set GPIO 6 to Btn, 7 to Rel, 8 to BL0937SEL, 10 to WifiLED_n, 24 to BL0937CF, and 26 to BL0937CF1. The posted JSON names the device “Power Metering Socket SWP86-01OG BL0937,” with flags set to 1024 and board set to CB2S. Those six assignments are the key settings that make relay, LED, button, and metering work together. [#20682308]

How do you calibrate voltage, current, and power readings on a BL0937-based socket after flashing OpenBeken?

Calibrate it with the same command style used in Tasmota: VoltageSet, CurrentSet, and PowerSet. The thread says this step is still required after flashing, even when the GPIO template is correct. Start with a known load and reference meter, adjust each value, and then save the results. Without calibration, the socket may switch correctly but report inaccurate energy data. [#20682308]

What are the exact front dimensions of the SWP86-01OG socket, including the depth from the front to the mounting plate, for fitting it into other wall frames?

The thread does not provide exact measured front dimensions or the front-to-plate depth. One user asked specifically about compatibility with other frames, and the author later said he could not check the dimensions. Another user contacted the seller, but no measurement follow-up appears in the supplied posts. For this thread alone, the correct answer is that the exact fit dimensions remain unpublished. [#20689539]

Why might SWP86-01OG sockets fail after mains outages or when powered from a generator, while simpler plug-in power meters keep working?

The thread points to power-quality stress as the likely trigger, not a confirmed single root cause. One report covers 3 units that failed after 3–5 months, usually after an outage and switchover to a generator. The same user suggests voltage problems or a non-pure sine waveform, and notes the sockets first showed wrong readings, then constant values, then no communication. That pattern fits progressive damage in the socket electronics rather than an immediate relay-only fault. [#20689421]

What is the BL0937 chip and how does it measure voltage, current, and power in a smart socket?

BL0937 is the socket’s energy-measurement chip in this hardware revision, and it works with a low-resistance shunt resistor to sense load data. “BL0937” is an energy-measurement IC that reads electrical parameters inside the socket, using a low-resistance shunt as its key current-sensing element. In the teardown, the author identifies BL0937 immediately and notes that voltage, current, and power are available after calibration through OpenBeken. [#20682308]

What is a Schuko socket, and how does it differ from plug systems that use a grounding pin?

A Schuko socket uses side grounding contacts rather than a central grounding pin. “Schuko” is a mains socket standard that grounds through side contacts, its key characteristic in this thread being incompatibility concerns with some plugs used in countries that expect a grounding pin. The author warns this can create grounding problems if someone inserts a plug that is not compatible with that system. Another user replies that many modern plugs are now uni-schuko. [#20682308]

How does CB2S compare with TWB2S1-ZR or other BK7231-based Tuya modules when flashing smart sockets?

CB2S and TWB2S1-ZR may need different expectations before flashing because the surrounding hardware can change. The original SWP86-01OG teardown shows CB2S with BK7231N and BL0937 metering. A later user reports a similar-looking unit with TWB2S1-ZR using BK7231T, no power meter, a 5 V AC/DC stage, and then a 3.3 V linear regulator. That means identical-looking sockets can expose different GPIO maps, power rails, and features. [#20840579]

What safety concerns should I watch for in a smart wall socket that uses a BP2525 non-isolated step-down power supply?

Watch for the lack of galvanic isolation. The teardown states the BP2525 stage is a simple step-down supply, not a flyback converter, and explicitly says there is no galvanic separation. That means low-voltage control circuitry can still sit in a hazardous mains-referenced design during service. The practical rule from this hardware is simple: do not probe, solder, or power-test it casually once installed or opened. [#20682308]

Why does the physical button stop working on a flashed CB2S socket even though the relay still toggles from software?

The usual cause in this thread is wrong or missing GPIO/button configuration after flashing. A 2025 user reports that software toggle still switches the relay, but the physical button does nothing and GPIO Doctor cannot detect the correct pin. That strongly suggests the relay output pin is mapped correctly, while the button input is not. On this platform, extracting the original Tuya configuration is the first recovery step suggested in-thread. [#21754369]

How can Tuya Config Extraction help recover button and GPIO assignments from a BK7231 smart socket after flashing?

It can recover the original Tuya pin assignments so you can remap the button and other functions correctly. In the 2025 follow-up, when a flashed CB2S socket lost its physical button, the first advice was to try Tuya Config Extraction. “Tuya Config Extraction” is a recovery method that reads saved device configuration data, its primary value being restoration of original GPIO and role assignments after flashing. If the file is valid, it can reveal the factory button mapping faster than manual probing. [#21754450]

What should I do when BK7231Flasher says an extracted Tuya file contains no configuration or cannot be read?

Update the flasher first, then assume the dump may not contain usable config data. In the thread, the user first got a read error when opening extracted files, then retried with BK7231Flasher v154 and obtained a result that seemed to contain no configuration. Another participant’s fix was simply “Try with latest flasher.” If the newest tool still shows no config, the thread offers no confirmed recovery beyond manual mapping or other extraction attempts. [#21754620]

Which flashing method works better for Tuya smart sockets today: OTA tools or direct serial flashing with BK7231GUIFlashTool and hid_download_py?

Direct serial flashing works better in this thread. In March 2024, the author states that most Tuya devices are now patched and says the serial approach is more reliable. Earlier, another user wanted OTA because desoldering CB2S was difficult, but no successful OTA path is shown for that case. The thread repeatedly points back to BK7231GUIFlashTool and hid_download_py for dependable flashing on these sockets. [#21017694]

How do I identify whether my smart socket variant really has energy metering hardware or is a different board revision without BL0937?

Open the socket and inspect the PCB for BL0937 and its shunt resistor. The metering version in the teardown clearly shows BL0937 plus a low-resistance shunt, and the published pin map includes BL0937SEL, CF, and CF1 on GPIO 8, 24, and 26. By contrast, a later variant is identified as TWB2S1-ZR with no power meter at all. If those BL0937 parts and pins are absent, treat it as a non-metering revision. [#20682308]

What’s the difference between the SWP86-01OG and similar models like the AVATTO N-WOT10-EU-W or W600/TW-02 variants discussed for OpenBeken?

The thread treats them as related but not identical hardware families. SWP86-01OG is the detailed teardown target and includes a published OpenBeken template for CB2S/BK7231N with BL0937 metering. AVATTO N-WOT10-EU-W is mentioned later only as a similar device under another model name. A W600/TW-02 variant is also linked as another posted revision. The practical difference is support data: only SWP86-01OG gets a full pin map and step-by-step flashing context here. [#21017694]

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