esp-nimble-cpp/examples/NimBLE_Stream_Server/README.md

NimBLE Stream Server Example

This example demonstrates how to use the NimBLEStreamServer class to create a BLE GATT server that behaves like a serial port using the familiar Arduino Stream interface.

Features

• Uses Arduino Stream interface (print, println, read, available, etc.)
• Automatic connection management
• Bidirectional communication
• Buffered TX/RX using ring buffers
• Similar usage to Serial communication

How it Works

1. Creates a BLE GATT server with a custom service and characteristic
2. Initializes NimBLEStreamServer with the characteristic configured for notifications and writes
3. Uses familiar Stream methods like print(), println(), read(), and available()
4. Automatically handles connection state and MTU negotiation

Usage

1. Build and flash this example to your ESP32 using ESP-IDF (idf.py build flash monitor)
2. The device will advertise as "NimBLE-Stream"
3. Connect with a BLE client (such as the NimBLE_Stream_Client example or a mobile app)
4. Once connected, the server will:
   • Send periodic messages to the client
   • Echo back any data received from the client
   • Display all communication in idf.py monitor

Service UUIDs

• Service: 6E400001-B5A3-F393-E0A9-E50E24DCCA9E
• Characteristic: 6E400002-B5A3-F393-E0A9-E50E24DCCA9E

These are based on the Nordic UART Service (NUS) UUIDs for compatibility with many BLE terminal apps.

Compatible With

• NimBLE_Stream_Client example
• nRF Connect mobile app
• Serial Bluetooth Terminal apps
• Any BLE client that supports characteristic notifications and writes