Is it possible to create a network of several ESP32 sending each other information?
I want to design a system where there are 3 ESP32 devices sending information to a central ESP32 but I also need any ESP32 in the system to be able to send information to anyone else.
Is it possible via Bluetooth BLE?
What you are looking for is a BLE mesh network.
At the moment, it is not implement for the ESP32 using Arduino IDE.
There is some support for IDF (beta version): https://github.com/espressif/esp-idf/tree/f1b8723996d299f40d28a34c458cf55a374384e1/components/bt/esp_ble_mesh
One of the best ways to exchange information is using MQTTT.
Alternatively, there is a protocol called ESP-NOW that allows you to create a network to communicate between ESP32 boards (we don’t have any tutorial about that). More information about ESP-NOW:
Examples with ESP-NOW: https://github.com/espressif/arduino-esp32/tree/master/libraries/ESP32/examples/ESPNow
I hope this helps.