esp-nimble-cpp/examples/NimBLE_Stream_Client

NimBLE Stream Client Example

This example demonstrates how to use the NimBLEStreamClient class to connect to a BLE GATT server and communicate using the familiar Arduino Stream interface.

Features

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

How it Works

1. Scans for BLE devices advertising the target service UUID
2. Connects to the server and discovers the stream characteristic
3. Initializes NimBLEStreamClient with the remote characteristic
4. Subscribes to notifications to receive data in the RX buffer
5. Uses familiar Stream methods like print(), println(), read(), and available()

Usage

1. Build and flash the NimBLE_Stream_Server example to one ESP32 using ESP-IDF (idf.py build flash monitor)
2. Build and flash this client example to another ESP32 using ESP-IDF
3. The client will automatically:
   • Scan for the server
   • Connect when found
   • Set up the stream interface
   • Begin bidirectional communication
4. Open idf.py monitor on each board to observe stream traffic

Service UUIDs

Must match the server:

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

Monitor Output

The example displays:

• Server discovery progress
• Connection status
• All data received from the server
• Confirmation of data sent to the server

Testing

Run with NimBLE_Stream_Server to see bidirectional communication:

• Server sends periodic status messages
• Client sends periodic uptime messages
• Both echo data received from each other
• You can send data from either idf.py monitor session