[ESP8285] SE831L intelligent garage door controller - interior, analysis

I will present here a short analysis of the interior and the firmware change of the WiFi SE831L/GD-DC5 garage door controller advertised as Sonoff eWelink. As a standard, I will free it from the cloud, give the procedure for changing its firmware and configurations of its GPIO. This time the discussed driver will be based on ESP, so there will be a little change from what I usually show. I showed the driver based on BK7231 some time ago in the topic WiFi garage gate controller, Smart Garage Opener Tuya - Home Assistant , there I also provided an example YAML configuration for HA, I will not repeat it here.

Purchase of the ECN SN kit
The set was bought on a Polish auction site for about PLN 73:

Let's take a look at its description so you know what kind of product it is:

Assembly instructions:






Received set
Let's see what we get in practice:

Everything is there, there is an opening sensor, there is a cable to connect the button, there is a USB cable for power supply, and the manual and the device itself are also present.

How does such a controller even work?
I already described this in the previous topic about the gate, there was a controller on CB3S (BK7231N):
WiFi garage gate controller, Smart Garage Opener Tuya - Home Assistant

The inside of the controller
I skip the tests with the manufacturer's application, we immediately look inside. Just pry the cover up.


The ESP8285 is directly on the PCB here. There is also AMS1117-3.3V, because ESP requires 3.3V, and the input is 5V from USB. There is also a small SOIC8 chip inside, STC 15W104 H41U58 2241.XA. It is a microcontroller, core 8051.

Pinouts:

There is nothing interesting on the bottom of the PCB:



Based on the photos, I made a list of connections - it will also be useful for setting the Tasmota's GPIO:

Only that... if there is an additional MCU here, how can we set the GPIO? About that in a moment.

Firmware change
You can easily upload Tasmota here. RX and TX is available. The UART port is not occupied by the MCU, it is not a TuyaMCU device. This microcontroller is on a regular GPIO.
GPIO0 is on the button, just press it before connecting the power.


esptool.py works, as I have already described several times:
https://www.elektroda.pl/rtvforum/topic3866386.html
The only thing left is what about the MCU...
My suggestion is to desolder it. First, we apply flux, then additional lead binder (we make bridges on its pins), and then we quickly heat both sides with a soldering iron. The layout can be removed after a while with tweezers:

And that's it for now. Then it is enough to make jumpers and program the Tasmot IO, but more on that another time.

Summary
Changing the firmware turned out to be very simple. At first I was worried about GPIO0, but it turned out that this signal is brought out to the button, so there was no problem with putting the ESP into programming mode. I also had concerns about this mysterious MCU, but it turned out that you can desolder it and just freely use the ESP8285 IO and script it as we like in Tasmot / Home Assistant.
I will try to show the configuration of the sensor itself, connecting it to the gate and a practical presentation soon, in a separate topic.
Does any of the readers have such "intelligent" (whatever it means - this is the language of advertisers) garage doors controlled by WiFi? There are no problems with the WiFi range Before gate? Maybe I'm just too skeptical. I invite you to the discussion.