Exploring the Features and Specifications of Tuya WiFi Energy Meter PJ-1103a [BK7231N][CB2S]

This is a TuyaMCU device. It has both MCU and WiFi module. We only flash WiFI module and then use our implementation of TuyaMCU protocol to use the MCU.

p.kaczmarek2 wrote:

This is a TuyaMCU device. It has both MCU and WiFi module. We only flash WiFi module and then use our implementation of TuyaMCU protocol to use the MCU.

Ohhh I see it now. After two days of fiddling with it I got it working.
The catch for me was to grasp the "TuyaMCU" vs. WiFi module concept, thanks for the insight!

Mine is a PJ1103C, it has a T1-M WiFi module (BK7238 based) and a N32G430 MCU for the TuyaMCU which interfaces with the HLW8112.
It seems to be working fine with the autoexec.bat from this topic (I've tested with a couple), the Openbeken page shows the readings fine. Only caveat is that I couldn't test the board when only connected to 3.3V, even the current sensors wouldn't report anything. (worth mentioning for other users: never try testing these devices on mains power with the case open)

Interesting, so they are really introducing now BK7238 series. It's good that we already have it supported.

Odd thing is that somehow the current direction detected on the B sensor of mine was inverted in one of my dual phase 220V lines. I double, triple and quadruple checked the arrow direction, the S1/S2 wirings and so on and the TuyaMCU always detected the direction of channel (dpID 6) B as reversed. Seems that the TuyaMCU calculates this automatically and you can't overwrite this boolean, any fixes for this aside from aliasing the channel and recalculating an absolute value? My current fix was to physically invert the clamp-sensor.

Also my main doubt: Is there a way to reset the Total energy counters? They seem to be stored in the TuyaMCU, is that right? Is there a command for that? I've looked around on the .md guide files on GitHub and couldn't find a command related to that.

small resume for PJ1103C, with a T1-M WiFi module (BK7238-based) and an N32G430 MCU for the TuyaMCU which interfaces with the HLW8112
Cut RX / TX trace

Flash with BK7238 firmware

Detail for RX / TX pin not good on previous photo

Rebuild the trace


autoexec.bat good for me

Thanks all, for your post, it's helped me

marschr wrote:

Also my main doubt: Is there a way to reset the Total energy counters? They seem to be stored in the TuyaMCU, is that right? Is there a command for that? I've looked around on the .md guide files on GitHub and couldn't find a command related to that.

I've figured this out by "RTFM" lol. So answering myself: it was easy as pressing the button on the box 5 times quickly and then all the cumulative counters are reset.

I wish that there was a way to erase the stored values from the tuyaMCU protocol but none of the "tuyaMcu_sendState" or "SetChannel" worked, the tuyaMCU internal logic rewrites the values on the openbeken a few moments later.

I have a similar device marked PJ1103C/V1.2 with T1-M (BK7238) + N32G430 + HLW8112.



I followed feiltom's approach (cut traces to isolate T1-M, flashed OpenBeken, reconnected traces), but using his or alexan's autoexec.bat config just gives me all zeros in the web UI.

Looking at the logs, I see the N32 is sending plain text debug output, not TuyaMCU protocol:

Quote:

Info:TuyaMCU:Consumed 150 unwanted non-header byte in Tuya MCU buffer
Info:TuyaMCU:Skipped data (part) 5B 49 2F 68 6C 77 5D 20 2A 2A 2A 2A 2A 43 48 41 2A 2A 2A 2A 2A 0D 0A 5B 49 2F 68 6C 77 5D 20 56 2F 46 72 65 71 2F 50 46 3A 20 32 33 30 30 2C 20 34 39 30 34 2C 20 31 30 30 0D 0A 5B 49 2F 68 6C 77 5D 20 49 2F 50 2F 45 3A 20 30 2C 20 30 2C 20 30 0D 0A 5B 49

Decoding this hex gives RT-Thread debug messages:

Quote:

[I/hlw] *****CHA*****
[I/hlw] V/Freq/PF: 2300, 4904, 100
[I/hlw] I/P/E: 0, 0, 0
[I/hlw] *****CHB*****
[I/hlw] I/P/E/PF: 0, 0, 0, 100

The readings seem valid (230.0V, 49.04Hz, PF 100%) — the N32 is clearly reading the HLW8112 correctly. But it's outputting plain text instead of TuyaMCU binary protocol (which I understand starts with 55 AA ...).

Is it normal that I see this debug output? Did anyone else encounter this with PJ1103C? If not normal, how do you get the N32 to switch to TuyaMCU protocol mode?

I am very new/inexperienced at this. Any advice appreciated!

On which pin do you see this plaintext?

Well, I can add support for parsing that, if it's really sent by MCU...

>>21768747

These messages appear in the OpenBeken logs from the TuyaMCU driver, which I understand reads from UART1. I see the same plaintext output when connecting directly to the board's TX/RX pads (the ones that bridge N32 ↔ T1-M). It seems I get plain text instead of TuyaMCU protocol?

>>21770525
Hi, new to the forum , hope we can help each other. from what i see you have the V1.2. With mine i didn't have to change the TX RX, juste flash with BK7238 and add this in the startup command line , you should see lots of things comming up:

startDriver TuyaMCU
tuyaMcu_setBaudRate 9600
tuyaMcu_defWiFiState 4
addRepeatingEvent 10 -1 uartSendHex 55AA0008000007
setChannelType 1 Voltage_div10
setChannelType 2 Frequency_div100
setChannelType 3 Power_div10
setChannelType 4 Current_div1000
setChannelType 5 PowerFactor_div100
setChannelType 6 EnergyTotal_kWh_div100
setChannelType 7 Power_div10
setChannelType 8 Current_div1000
setChannelType 9 PowerFactor_div100
setChannelType 10 EnergyTotal_kWh_div100
setChannelType 11 ReadOnly
setChannelType 12 ReadOnly
setChannelType 13 Power_div10
linkTuyaMCUOutputToChannel 112 val 1
linkTuyaMCUOutputToChannel 111 val 2
linkTuyaMCUOutputToChannel 101 val 3
linkTuyaMCUOutputToChannel 113 val 4
linkTuyaMCUOutputToChannel 110 val 5
linkTuyaMCUOutputToChannel 106 val 6
linkTuyaMCUOutputToChannel 105 val 7
linkTuyaMCUOutputToChannel 114 val 8
linkTuyaMCUOutputToChannel 121 val 9
linkTuyaMCUOutputToChannel 107 val 10
linkTuyaMCUOutputToChannel 102 raw 11
linkTuyaMCUOutputToChannel 104 raw 12
linkTuyaMCUOutputToChannel 115 val 13
setChannelLabel 1 "Tension"
setChannelLabel 2 "Frequence"
setChannelLabel 3 "Puissance A"
setChannelLabel 4 "Courant A"
setChannelLabel 5 "PowerFactor A"
setChannelLabel 6 "Energie A"
setChannelLabel 7 "Puissance B"
setChannelLabel 8 "Courant B"
setChannelLabel 9 "PowerFactor B"
setChannelLabel 10 "Energie B"
setChannelLabel 11 "Direction A"
setChannelLabel 12 "Direction B"
setChannelLabel 13 "Puissance nette"

More things to come up i'm sure, cause i didn't check for the buzzer yet or else, but can easily be found.i'll try to udpate this.
Hope it 'll help

Frath