Implementing DIY Geiger counter J321 2019 Model

I thought at the beginning that the DIY geiger counter is great with a display that may have a simple RX/TX communication. As you can see in the picture. But it is not so. The traces of the wires go from the H1 connector to the U5 chip. The same applies to the USB1 connector. But there is no communication. I don’t know why it has 2 USB ports. But the second one is only for the power supply. I thought I would just hijack the LED and connect it to an ESP32 if there were no other options. It also has 2 non-executed buttons. One is for turning off the buzzer (the left one at the bottom) and the 2nd one I have no idea about. Does anyone have that Geiger counter and was able to implement it?

I’ve found out it has a SSD1306 OLED Display.
I’ve also figured out, what pin what does but im also not able to communicate directly.

Does someone know how can I identify that chip or where can I start search?

If your question is still open, we have a suggestion:
try connecting to the UART console of this device via the USB connector.
If the device sends radiation measurement data to the console, it is possible to connect it via a custom UART text sensor in ESPHome. We are currently developing a similar connector (YAML config & C++ handler code) for our new Geiger counter emulator product and have already gone through this path. The idea is that the device itself can send text messages to the UART console. By connecting to the Tx pin of the controller on the device board on the one hand, and for example to the Rx of the ESP8266/ESP32 on the other hand, it is possible to receive this text in the sensor and then process it as a normal ESPHome/HA sensor.
Do an experiment with your board. If you can connect a regular USB-UART console and see text data at a certain serial connection speed, let us know and we will help you make a connector to receive this data in ESPHome and then in Home Assistant.
Oleksii Yanko
Team IoT-devices, LLC