Deltaco SH-P01, SH-P01-3P Teardown and BK7231T Flashing Guide with WB2S WiFi Module

Hello,

Here's the teardown for the smartplug Deltaco SH-P01 and SH-P01-3P.
Serial: PO194180
https://deltaco.se/sh-p01 (260106)



These have been available, and still are, in the Swedish store Clas Ohlson.
https://www.clasohlson.com/se/Deltaco-smart-plug-SH-P01-inomhus/p/36-8479 (260106)

The WiFi module in these is the WB2S and I have successfully flashed
the BK7231T firmware on eight of these.







However I had to destroy one to open it since they are glued.
The rest I saw a hole on the side to be able to solder
VBAT, GND, RX, TX to a generic USB2TTL adapter I got from eBay.
The pin connection should be:
Adapter pin - WB2S pin
3.3 V - VBAT
GND - GND
TXD - RX
RXD - TX

The adapter uses a CH340G chip, so Windows needs drivers for this to
add a virtual COM port when inserted into USB. I run Windows 10 and probably
downloaded the driver here (it can be found on other places):
https://cdn.sparkfun.com/assets/learn_tutorials/8/4/4/CH341SER.EXE (260106)
https://www.ebay.com/itm/141976858044 (260106)









I downloaded the software (v176) to flash from here:
https://github.com/openshwprojects/BK7231GUIFlashTool/releases
And the flasher downloaded this image:
OpenBK7231T_UA_1.18.226.bin

The pins are configured as:
Button : pin 6
WiFi-LED: pin 8
Relay : pin 24

This is the configuration used in the webapp that OpenBekenIOT uses:



/Ola Löfberg

Good idea, it's certainly better than tearing apart whole plug.

Did you really manage to flash it while powering directly from USB to UART 3.3V pin? That's not very reliable, but still, you're lucky that it worked out well.

Don't forget to add PowerSave 1 command to the startup line, those devices have low quality power supplies.

On powersave:

Will try it. I was quite surprised that the Wi-Fi module got that hot. I think it has an internal temp sensor that
shows about 65 °C when running.
EDIT: With PowerSave 1, it draws about 2mA (relay off), 6mA (relay on), and about 6mA if you (230VAC)
look at the startpage, monitoring heat. I guess thats the websocket connection that has to be running.
If it is just idling it seems to be running at abount 30 degerees C.

One of these stopped working yesterday. I wonder if it's the heat that is the problem?

I had no problem driving it by 3.3 V but now when you mention it, I've seen people using a separate supply for it.

/Ola

The internal temperature sensor is not very accurate, but still, 60 doesn't sound hot to me. I've seen worse.

That being said, PowerSave 1 always helps, and it's not really about WiFi module heating, but rather about capacitors in the power supply, that cheap one, which Tuya used.

Btw do you have original factory flash backups? We're collecting them with @divadiow

backup received thanks.
boot log


I see a "vtrust-flash" AP was used at some stage. Did you attempt Tuya-convert on it?

Yes, I think I tried that before deciding to open them.
Coincidence that that specific device was the one I backed up much later...

As I remember, Tuya-Convert failed.

cool. https://github.com/OpenBekenIOT/webapp/pull/254