What components are inside the EARU EAWCPT-J?
The board carries a CBU Wi-Fi module with a BK7231N SoC, a BL0942 energy-measurement chip, opto-drivers for the bistable relay, and two panel LEDs [Elektroda, flobuljeedom, post #20842835]
[BK7231N / WC1H] EARU DIN Rail relay EAWCPT-J (with energy meter)
TL;DR
- Teardown of the EARU EAWCPT-J 35mm DIN rail WiFi smart relay with energy metering, based on BK7231N/WC1H, BL0942 and a CBU module.
- The enclosure opened by drilling the 6 holding screws and separating the shields, then wiring RX1, TX1, 3V3 and GND to an FTDI232.
- UART access worked only at 9600 baud rate, which allowed JSON and configuration extraction from the firmware.
- Voltage, current and power were calibrated after extracting the configuration.
- A limitation remained: when the relay is down, Active Power and Power Factor show negative values even with Flag 38 checked, and the original firmware backup was saved.
Generated by the language model.
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
First, drill the 6 holding "screws" and push them through. And split the shields.
WC1H - BL0942 - CBU :
From CBU pins :
Soldered to RX1, TX1, 3V3 and GND and connected to FTDI232 :
Reading only worked with 9600 baud rate :
json and configuration extracted:
My current template:
Startup command:
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.
Here is the original firmware backup:
35mm Din Rail WIFI Smart Switch Remote control byTuya APP for Smart home from https://fr.aliexpress.com/item/1005005903760507.html
First, drill the 6 holding "screws" and push them through. And split the shields.
WC1H - BL0942 - CBU :
From CBU pins :
Soldered to RX1, TX1, 3V3 and GND and connected to FTDI232 :
Reading only worked with 9600 baud rate :
json and configuration extracted:
Code: JSON
Code: Text
My current template:
Code: JSON
Startup command:
Code: Text
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.
Here is the original firmware backup:
Comments
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]
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]
As I wrote, drill it [Read more]
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]
I used M3 screws and bolt I had in my drawer [Read more]
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]
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]
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]
***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]
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]
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]
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]
. 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]
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]
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]
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]
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]
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]
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]