Control ESP32 board from your Android phone, using the RoboRemo app.
RoboRemo can connect via Bluetooth (RFCOMM / BLE), WiFi (TCP / UDP / TCP Server), USB Serial.
In this example, the ESP32 is configured as Bluetooth Low Energy (BLE) device, with ginen name "ESP32-BLE"
Android Phone is paired to the "ESP32-BLE" device. (If cannot find device / cannot pair, please try: restart phone / restart Bluetooth / Settings -> Connected devices -> See all -> "ESP32-BLE" -> Forget).
Then RoboRemo app connects (via Bluetooth BLE) to the "ESP32-BLE" that is already paired.
Bi-directional real-time communication is achieved.
Project can be further extended in order to build a Bluetooth-controlled IoT device, robot, etc. based on ESP32 boards.