Connection Issue Between Gear and iPhone via Bluetooth LE

Original Created Jan 11, 2018 | Regeneration Apr 22, 2026

Question

I'm developing an application where a Gear device connects to an iPhone using Bluetooth LE, with Gear as Central and iPhone as Peripheral. I'm encountering an issue during the connection process.

Here's my implementation flow:

Initialize Bluetooth:

bt_initialize();
bt_adapter_get_state(&state);
if (state == BT_ADAPTER_DISABLED) {
    return error;
}

Start scanning:

bt_gatt_set_connection_state_changed_cb(__bt_gatt_connection_state_changed_cb, NULL);
bt_adapter_le_start_scan(__bt_adapter_le_scan_result_cb, NULL);

Logs confirm the service with requested UUID (00001101-0000-1000-8000-00805F9B3400) is found.

Stop scanning after device discovery:

bt_adapter_le_stop_scan();

Attempt connection:

bt_gatt_connect(iphone_address, true);
bt_gatt_client_h client_handle = NULL;
bt_gatt_client_create(iphone_address, &client_handle);

The error occurs when trying to create a GATT client:

Fail wc_bt_get_gatt_client_service[9a3f68e0-86ce-11e5-a309-0002a5d5c51b]/[-61]

Error -61 (BT_ERROR_NO_DATA) suggests the service with UUID 9a3f68e0-86ce-11e5-a309-0002a5d5c51b is not found, though this UUID isn't in my code.

Answer

Problem Understanding

The issue occurs when attempting to establish a BLE connection between Gear (Central) and iPhone (Peripheral). The error suggests the system is looking for a service UUID that isn't explicitly requested in the code.

Solution Methods

Initial Connection Setup:
- Ensure the Gear is first connected via the official Gear S app (Gear Manager on Android)
- This establishes the necessary baseline connection before your custom app attempts communication
Service Discovery:
- After connection, explicitly discover services using:
```
bt_gatt_client_discover_services(client_handle);
```
Error Handling:
- Implement proper error handling for service discovery failures
- Verify all required services are properly advertised by the iPhone peripheral

Code Examples

// After successful connection
if (bt_gatt_client_discover_services(client_handle) == BT_ERROR_NONE) {
    // Service discovery successful
    // Proceed with characteristic discovery
} else {
    // Handle discovery failure
}

Additional Tips

The mysterious UUID (9a3f68e0-86ce-11e5-a309-0002a5d5c51b) appears to be an internal service required by the Gear system
Always verify Bluetooth permissions in your Tizen manifest
Consider connection timeouts and retry mechanisms
Test with different iOS versions as BLE behavior can vary