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[BK7231N / WC1H] EARU DIN Rail relay EAWCPT-J (with energy meter)

flobuljeedom 
This is my teardown of EARU EAWCPT-J relay.
35mm Din Rail WIFI Smart Switch Remote control byTuya APP for Smart home from https://fr.aliexpress.com/item/1005005903760507.html
EARU EAWCPT-J WiFi Smart Switch for DIN Rail View of the back part of a white DIN rail relay housing.

First, drill the 6 holding "screws" and push them through. And split the shields.

Disassembled smart WIFI relay for DIN rail.

WC1H - BL0942 - CBU :
Close-up of the interior of a relay housing showing electronic components, including capacitors and a microchip. Close-up of an electronic module labeled CBU on a circuit board.

From CBU pins :
Bottom view schematic of the PCB with pin numbering and dimensions.

Soldered to RX1, TX1, 3V3 and GND and connected to FTDI232 :
The image shows a USB FTDI adapter with attached wires and a glowing LED. Close-up view of the internal components of a WiFi smart switch on a Din rail. EARU relay board with wired connections EARU EAWCPT-J relay circuit with connected FTDI232 module.

Reading only worked with 9600 baud rate :
BK7231 Easy UART Flasher software interface with visible operation log. Screenshot of BK7231 Easy UART Flasher showing successful firmware write.

json and configuration extracted:
Code: JSON
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Code: Text
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My current template:
Code: JSON
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Startup command:
Code: Text
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I then calibrated Voltage, Current and Power.
Just one issue, when relay is down, "Active Power" and "Power Factor" indicate negative value, even with Flag 38 checked.

Screenshot of the OpenBK7231N user interface displaying relay information.


Here is the original firmware backup:

About Author
flobuljeedom wrote 16 posts with rating 85 , helped 1 times. Live in city Paris. Been with us since 2023 year.

Comments

flobuljeedom 12 Feb 2024 14:27

Concerning the issue with negatives/positives values when relay is OFF, I figured it out. I changed pins 24 and 26 to "BridgeFWD" and "BridgeREV". Updated template as well. [Read more]

brunovier 06 May 2024 04:45

Hello @flobuljeedom, how did you opened and closed it without broken it? I open mine forcing the plastic and the final result was not very good. I have no idea how to close it without tape :). [Read more]

flobuljeedom 06 May 2024 07:15

As I wrote, drill it [Read more]

imarin2 21 Jun 2024 20:53

Thank you. The GUI Flash app did not work for me. It ended with write failure. However, the python "obsolete" method worked fine: python3 uartprogram OpenBK7231N_QIO_1.17.621.bin --unprotect... [Read more]

flobuljeedom 21 Jun 2024 20:55

I used M3 screws and bolt I had in my drawer [Read more]

imarin2 21 Jun 2024 21:25

Nice idea. I had a couple of M1.5 bolts around (12mm long). They fit tight inside the hole of the drilled rivets. So I used them to thread the inside of the rivets (so one side you see the original... [Read more]

daxliniere 21 Aug 2024 11:13

Hey @flobuljeedom, thanks so much for posting this. I have flashed with your config file, but for some reason the red LED which should be 'mains power present' is illuminated (it also flashes during bootup)... [Read more]

Agetommy 26 Sep 2024 18:39

Ich have trouble to switch the the bistable relay in this device. I have definde the output pins as BridgeFWD and BridgeRE (like the JSON in this thread) "24": "BridgeFWD;1", "26":... [Read more]

theunknown 29 Oct 2024 12:09

***CBU MODULE ON THE BACK? CHECK FIRST POST*** ***CBU MODULE ON THE FRONT? SEE BELOW*** It seems there has been a hardware revision for the EAWCPT-J. The CBU module is now on the front of the board,... [Read more]

abaku 20 Feb 2025 09:07

I have just received the EAWCBT-J I'm assuming it's from current production, internally it looks identical to post #10, I uploaded OpenBK7231N using BK7231Flasher, I didn't solder - I used acupuncture... [Read more]

p.kaczmarek2 20 Feb 2025 12:03

If you used this template: "pins": { "6": "LED_n;1", "7": "Btn;1", "8": "WifiLED_n;0", "24": "BridgeFWD;1", "26": "BridgeREV;1" }, ... [Read more]

abaku 21 Feb 2025 14:50

Hello, thank you for your reply and above all for what you are doing for open source yes i used this template, i didn't manage to archive the original configuration but i will measure from nature which... [Read more]

p.kaczmarek2 21 Feb 2025 15:47

. But nothing needs to be archived here. The Tuya config partition is still there after flashing. It is not deleted. As long as you don't deliberately perform a 2MB erase of the entire flash then it doesn't... [Read more]

abaku 22 Feb 2025 10:35

measurement with meter ~10mA ~240V = 2.4W and indicates 12W tuya configuration: (never been added to the cloud) { "bt1_pin": "15", "led1_pin": "6", "rl1_drvtime": "60", "net_trig":... [Read more]

p.kaczmarek2 22 Feb 2025 10:38

Do you know about the calibration process? As in Tasmot. VoltageSet, CurrentSet, PowerSet commands. Also you can through the Web App under Tools, there is a ready form there. [Read more]

abaku 22 Feb 2025 11:01

I did according to the indicated video tutorial and .... in web application/import generated such a script: clearIO // clear old GPIO/channels lfs_format // clear LFS StartupCommand "" // clear... [Read more]

p.kaczmarek2 24 Feb 2025 10:01

Thanks for pointing this out - I see that on the Web App the importer did not have bridge relay implemented. Only on the windows app was it entered. I have corrected it: https://obrazki.elektroda.pl/8598134300_1740387701_bigthumb.jpg... [Read more]

abaku 24 Feb 2025 19:52

EARU EAWCPT-J In this version (delivery 02.2025), the location of the LED POWER and LED WIFI is changed https://obrazki.elektroda.pl/7131103900_1740038535.jpg working template: { "vendor": "Tuya", ... [Read more]

p.kaczmarek2 24 Feb 2025 19:55

Thanks for the template, but if you can put it in a syntax json tag. Is everything working now? How about the power consumption? As for the LED, it's at your discretion - some want it to light up... [Read more]

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