[BK7231N] QCNX Plug with Smartmeter: ESP Chip, MQTT, Tasmota, OpenBK Firmware & Pin Settings

Question

I recently purchased a QCNX Plug because I thought they had an ESP chip, to find that they are using a BK7231N Since I already had the UART interface soldered (trying to flash Tasmota and failing on the process), I checked the chip and found the BK7231N inscription so I downloaded the OpenBK...

p.kaczmarek2 · Answer

Hello, have you opened the device to do the flashing? The simplest way is to follow the traces on the board.
Or maybe do you happen to have 2MB firmware backup, so we can import pin settings from that?
Is the BK7231N inside in the CB3S form module? Maybe we could map TYWE3S pins to CB3S... or TYWE2S to CB2S.

sirlouen · Answer

I've done a backup of the firmware. I will upload it here this evening. Added after 1 [hours] 22 [minutes]: Here I attach the 2MB firmware BIN to see if we can find the GPIO pins for the power meter Also I've noticed that after I plug in the socket the button works, but after 2 hours or so, it doesn't work anymore. Not sure why.

p.kaczmarek2 · Answer

Is the Webpage still working after two hours? Is switching relay from WWW panel works?
I have forwarded the binary for analysis, I will (hopefully) have pinout later today.
Please try adding PowerSave 1 command to startup command line in OBK to reduce the power usage of the device and increase it's stability, this helps with the cheapest devices that has low quality power supplies

sirlouen · Answer

The whole system works after 2 hours, I can access the web interface and that. It's only the button to power on/off that stops working

p.kaczmarek2 · Answer

I don't have analyzed dump yet, but can you try: CF on P9 (ESP GPIO04), CF1 on P8 (ESP GPIO05), Sel on P24 (ESP GPIO12)? Those are mappings based on Tasmota template.

Btw, it's worth to add a screenshot of the device:

Added after 10 [minutes]:

update:
I can't see anything more than that in binary:


{
	"bt1_lv": 0,
	"bt1_pin": 10,
	"bt_type": 0,
	"ch_cddpid1": 9,
	"ch_dpid1": 1,
	"ch_num": 1,
	"crc": 94,
	"ffc_select": 0,
	"jv": "1.1.5",
	"module": "CB2S",
	"net_trig": 1,
	"netled1_lv": 0,
	"netled1_pin": 8,
	"netled_reuse": 0,
	"netn_led": 1,
	"nety_led": 2,
	"reset_t": 3,
	"rl1_lv": 1,
	"rl1_pin": 26,
	"total_stat": 2
}

Relay on P26, WiFi LED on P8, button on P10.

Maybe it's without energy meter? Or maybe it's BL0942? Remove BL0937 pin setting, reboot, and try "startDriver BL0942"...

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.

sirlouen · Answer

I've switched to BL0942 With pins format Code: text Expand Select all Copy to clipboard  pins: {     8: WifiLED_n;1,     10: Btn;1,     26: Rel;1   }, Using the bootload command Code: text Expand Select all Copy to clipboardbacklog startDriver BL0942; VREF 15987.125000; PREF -683.023987; IREF 272302.687500 From ELVCO LSPA9 Power metering plug I have not set any of the CF, CF1, parameters.

p.kaczmarek2 · Answer

Sorry, but is it working now?

sirlouen · Answer

It was working already, but not the power meter functionality.

p.kaczmarek2 · Answer

So it's not BL0942?

The JSON config from binary file doesn't seem to contain anything about BL0937.... but the binary has BL0942 string inside so it might be BL0942 based device:

This is why I asked you to start BL0942 driver and try. Are you getting and correct readings on WWW panel?

sirlouen · Answer

BL0942 is loaded This is the pins I currently have config'd.

p.kaczmarek2 · Answer

Hmm no resutls here. Well, maybe we just try looking inside? You already had a flash dump, so you must have already opened the device. You can easily check with multimeter where the signals are going.

sirlouen · Answer

I'm not that expert in electronics Some guide on how I can do this?

p.kaczmarek2 · Answer

Well, let's start with some photos from inside. Where is the BL0937 and where is WiFi module? Is WIFI module in CB2S form?

sirlouen · Answer

There is CB2S:

p.kaczmarek2 · Answer

I am sorry to say this but the photos confirms the data from the binary. It seems there is no power metering chip in this plug. There is only an empty place for one, which matches BL0937 footprint:

If you want, you can post more photos so we can double check, because maybe I am missing something, but it really seems that this plug has no power metering chip.

Did you test that device with original Tuya app? Did it have power metering?

sirlouen · Answer

I did not test the Tuya app. I installed this straight away.

More images

I specifically bought the model with power monitor. There was a cheaper model without power monitor

16A Power Monitor, EU, 100-250V, China

p.kaczmarek2 · Answer

Can you look here?
Tuya LSPA9 smart socket - teardown, OpenBeken flashing guide for CB2S, BL0942
This is my old LSPA9 teardown. The power metering sockets have the SOIC/SO/SSOP chip populated, here:

They also have a shunt resistor populated, because it is required to do measurements. By measuring a voltage drop on shunt resistor, and knowing the resistance value, the current can be calculated.

Your device, on other hand:

has no BL0942/BL0937 IC and furthermore, the is no shunt resistor - it is replaced with a jumper soldered in it's place.

I am sorry, but I am 100% sure that your device has no power metering capability. Please open a ticket/dispute on Aliexpress and you may try to receive a refund. I had issues with them several times, but usually they refunded the money. At least part of it.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.

sirlouen · Answer

Ok, dispute opened. I've bought a couple more last week with theoretically power metering functionality. Let's see if they come with such BL controller So basically now we have a new device. The QCNX without power meter version. They sent me the wrong one. Still the pins I set here Are not working well. I will also unload the BL driver because it's useless in this case.

p.kaczmarek2 · Answer

Was the power metering advertised on original packaging and manual? Maybe it was just one time mistake by them.

[BK7231N] QCNX Plug with Smartmeter: ESP Chip, MQTT, Tasmota, OpenBK Firmware & Pin Settings

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