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Bluetooth BLE writeCharateristic problem.

  • Hi,
    I am trying to make a simple Pc software able to communicate with my Bluetooth BLE peripheral.

    My BLE peripheral includes a Custom Service (named as “Server_UART" with UUID 0003CDD0-0000-1000-8000-00805f9b0131 ) witch has two Characteristic:

    • Server_UART_Tx_data (UUID 0003CDD1-0000-1000-8000-00805f9b0131 ) with Notify Property and a Client Characteristic Configuration Descriptor to Notification enable
    • Server_UART_Rx_data (UUID 0003CDD2-0000-1000-8000-00805f9b0131 ) with
      WriteWithoutResponse Properties.

    Using heartlistener demo project (QT Demo project Page) as example, I realized a software able to scan, recognize and receive data from my Bluetooth BLE peripheral.
    Any data sent from my BLE peripheral, arrived to my PC application and I am able to catch them.

    Now, I want send data from my PC application to my bluetooth BLE peripheral.
    I tried with this code:

    void HeartRate::write(QByteArray data){

    // Take Charateristic UUID - 0003CDD2-0000-1000-8000-00805f9b0131
    const QLowEnergyCharacteristic hrChar = m_service->characteristic(
    if (!hrChar.isValid()) {
        setMessage("Data not found.");


    Nothing Happens!
    No error signal is triggered by the service, no data arrived on BLE peripheral, nothing happens.

    My BLE peripheral works because I tried with another App and all worked well.

    Have you any idea?
    Is there another way to write data into a specific BLE Characteristic?

    My O.S. is Ubuntu 14.04 (32-bit) and Qt 5.5.


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