private void buttonSetBT_Click(object sender, EventArgs e)
 {
     if (textBoxBTName.Text == "")
     {
         MessageBox.Show("Bluetooth Name cannot be empty !");
     }
     else if (textBoxBTName.Text.Length > 15)
     {
         MessageBox.Show("Bluetooth Name length is limited to 15 bytes !");
     }
     else
     {
         MyFocuser.SetBluetooth(textBoxBTName.Text);
         MessageBox.Show("Please refresh your Bluetooth device to see if it succeeds !");
     }
 }