[BK7231T / WB2S] Teardown Kruidvat Smart Plug Dual (with Energy Meter)

Hi,
I am adding a teardown for my Kruidvat SMART Dual Plug. I bought this Smart Plug out of curiosity. The Plug can be converted using tuya-cloudcutter and it took me about one hour from the package to full operating mode in HomeAssistant. Somehow MQTT did not pick up instantly, and after reprovisioning, it went fine.


Even though I don't want to install anything tuya related on any of my devices, I recommend installing the tuya or a compatible app on a spare device. The reason for doing so is to get the smart device's firmware version. We need this version number for uploading the OpenBeken firmware using tuya-cloudcutter. I am fond of opening devices and understanding how they work inside. But in the end, the likelihood of destroying/bricking a smart device is much greater when you are playing around with a soldering iron than with flashing using tuya-cloudcutter. Until now I've not broken any smart plug by the tuya-cloudcutter method.

Well, let's start with unboxing;

Packaging:



Nothing out of the ordinary. The important information here is the article number: "SH 63.126".

Now for the physical appearance:


And the inside:


And now, the stuff we care about;
The unit comes with a WB2S Tuya module. And I can confirm it is correctly labeled. The chip is a BEKEN BK7231T, which makes it compatible with OpenBeken.

The pictures are not the best, as the Tuya board is mounted closely to the internal chassis parts that make up the socket and relay.


And now, what makes this Plug such a good purchase? The BL0937


This unit came with MCU version 1.3.5. I need the version number for cloud-cutter. Unfortunately, I've not found an easy way to recover the build number without installing the Tuya Cloud software. For now, it is fine as I am using an old android device that I disconnect from the internet.


The cloud-cutter ran as expected.
Based on the firmware version (1.3.5) I selected the Generic Tuya NAS WR07W 16A smart plug.

After the unit was flashed, I connected to the AP, ran my default provisioning for adding the device to my network and rebooted the plug.

Once connected, I configured the PINs.
P6 BL0937SEL
P7 BL0937CF1
P8 BL0937CF
P10 Btn 1
P11 Wifiled_n
P23 Btn 2
P24 Rel1
P26 Rel2

Some tweaking; Selected Flag 6 for instant switching

Configured MQTT and it works perfectly



As the BL0937 seemed uncalibrated, I had to do some calibration. The voltage was set to 220V, but we ran around 234V. So with the VoltageSet command, I corrected this. The load value was 60Watt, using a 60 watts light bulb. So no calibration is needed there. I would like to do a posting on calibrating the BL0937 sockets but may be some one has already done so.

So I hope my teardown and walk true are helpful. I can strongly recommend these plugs in case you need dual power sockets.
The BL0937 makes it the cheapest dual plug I have found so far.

Niels