Antela UK Smart Plug with CB2C (B7231N) & BL0937: No Energy Readings in ESPHome/OpenBeken

Hi,

I have an Antela UK smart energy monitoring plug. I have designed and 3D printed a jig to press the plug open and found that it has a CB2C WiFi module (B7231N chipset) with a BL0937 energy monitoring chip. I've 3D printed a little connector to slip under the board to make contact with the relevant pins so I can flash it. Then successfully flashed it with both ESPHome and with OpenBeken. I've used a multimeter to discover the button, LED, and relay pins, and configured both ESPHome and OpenBeken and they all work fine on either platform. However, I cannot get the energy monitoring side of things to give me anything really. I have found that on the CB2S module, the following are connected to the BL0937:

P7 -> CF
P6 -> CF_1
P8 -> SEL

In both ESPHome and OpenBeken I just get 0.0 voltage, current and power. I've tried all forms of calibration and nothing really seems to give me anything resembling success. Does anybody have any insights?

coximus wrote:

P7 -> CFP6 -> CF_1P8 -> SEL

how confident are you of these assignments? if you took flash backup did you try config extraction in Easy Flasher?

Thanks for the suggestion, I've predominantly been using some raw tooling in Linux for dumping and flashing firmware, so I hadn't come across the fact I can extract config from the dumped firmware.

It does look like I'm correct though in my pin assignment (unless I'm reading this wrong) .... This is what I have obtained from "BK7231 Easy UART Flasher" from the original dumped firmware:

Device configuration, as extracted from Tuya:
- BL0937 SEL on P8
- Button (channel 1) on P26
- BL0937 VI on P6
- WiFi LED on P11
- BL0937 ELE on P7
- Relay (channel 1) on P24
Device seems to be using CB2S module, which is using BK7231N.
And the Tuya section starts, as usual, at 2023424

{
"sel_pin_pin":"8",
"rl1_lv":"1",
"bt1_pin":"26",
"net_trig":"2",
"jv":"1.0.3",
"netled1_lv":"1",
"netled_reuse":"1",
"bt1_type":"0",
"ffc_select":"0",
"vi_pin":"6",
"resistor":"1",
"over_cur":"17000",
"bt1_lv":"0",
"reset_t":"3",
"netled1_pin":"11",
"chip_type":"0",
"lose_vol":"90",
"over_vol":"260",
"module":"CB2S",
"ele_pin":"7",
"ch_cddpid1":"9",
"ch1_stat":"2",
"rl1_type":"0",
"ch_num":"1",
"ele_fun_en":"1",
"rl1_pin":"24",
"vol_def":"0",
"ch_dpid1":"1",
"sel_pin_lv":"1",
"crc":"80"
}

Do any of those numbers make sense to anybody to help configure either ESPHome or OpenBeken to work with this setup?

is the BL0937 driver running for sure? did you de-solder the CB2S to flash? maybe a trace is damaged or not soldered quite right?

So I didn't de-solder the chip, I've printed this little caddy and slipped it under the chip to flash it in place .... I'm not sure if this is anything new, I'm happy to share details on this if anybody is interested?



I do believe the driver for the BL0937 is running based on the screenshot .... I did play around in the OpenBeken Tools menu, and when the plug was under load I set the voltage, current and attempted to set the power values (though setting power failed). With some load going through the plug voltage does fluctuate seemingly at intervals showing either a value of 0.00 or 230v (sometimes over 400v), and current does similar (varies between some value and 0.00), however Power always shows 0.00