BLE hid Keyboard key press/release [Clarifications needed]

[abdelali]

Hi,

We're working on a ble hid keyboard project, and we need some clarifications on how the keyboard keys press/release is done !

We've started with the example in the sdk v16.0.0, the example uses the keys_send() function to send a press followed by a release of that key. 

In this function there is  send_key_scan_press_release() , and i think this is the responsible for sending a press followed by a release of the key.

In our use case, we need to send just a press when the button is pushed, and a release when the button is released. in this case a hold on the button will output a successive key presses , and when released it will output just one release . this is achieved with the USB keyboard version using the app_usbd_hid_kbd_key_control() function.

 static void button_event_handler(uint8_t pin_no, uint8_t button_action)
    {
      ret_code_t err_code;
      switch(pin_no)
      {
       case BUTTON_1:
         if(button_action == APP_BUTTON_PUSH) {
            UNUSED_RETURN_VALUE(app_usbd_hid_kbd_key_control(&m_app_hid_kbd, CONFIG_KBD_KEY[0] , true));
            //NRF_LOG_INFO("button1 pressed");
         }
         else if(button_action == APP_BUTTON_RELEASE) {
            UNUSED_RETURN_VALUE(app_usbd_hid_kbd_key_control(&m_app_hid_kbd, CONFIG_KBD_KEY[0] , false));
            //NRF_LOG_INFO("button1 release");
         }
         break;
         
         }
    }     

the BLE  hid keyboard output on the host, should be as in the picture bellow (same as with the USB version) : 

Any help, clarifications, recommendations on how to achieve that is highly appreciated !

Best Regards,

Abdelali

[abdelali]

Hi,

thank you,

Yes i did. and here is the button handler i use to test it :

static void button_event_handler(uint8_t pin_no, uint8_t button_action)
{
  ret_code_t err_code;

  uint8_t  data[INPUT_REPORT_KEYS_MAX_LEN];

  switch(pin_no){

   case BUTTON_1:

      if(button_action == APP_BUTTON_PUSH) {
      
            memset(data, 0, sizeof(data));
            data[2] = 0x04;

            err_code = ble_hids_inp_rep_send(&m_hids,
                                             INPUT_REPORT_KEYS_INDEX,
                                             INPUT_REPORT_KEYS_MAX_LEN,
                                             data,
                                             m_conn_handle);

            if(err_code != NRF_SUCCESS) NRF_LOG_INFO("err : %x; \n",err_code); 

            NRF_LOG_INFO("button1 PUSHED");      
      
      }

     else if(button_action == APP_BUTTON_RELEASE) { 
     
           memset(data, 0, sizeof(data));    
           err_code = ble_hids_inp_rep_send(&m_hids,
                                             INPUT_REPORT_KEYS_INDEX,
                                             INPUT_REPORT_KEYS_MAX_LEN,
                                             data,
                                             m_conn_handle);

           if(err_code != NRF_SUCCESS) NRF_LOG_INFO("err : %x; \n",err_code); 

           NRF_LOG_INFO("button1 RELEASED");    

      }


     break;

 }

}

But even that, the same output!

[*] tested on an Android device :

Best Regards,

Abdelali

[Kenneth]

I am not sure what key code 0x04 is, however it would be interesting to get a sniffer log of the on-air communication here:
https://infocenter.nordicsemi.com/topic/ug_sniffer_ble/UG/sniffer_ble/intro.html 
https://www.nordicsemi.com/Software-and-tools/Development-Tools/nRF-Sniffer-for-Bluetooth-LE/Download#infotabs

Best regards,
Kenneth

[bharatb4196]

Has anything been followed up on this, with the press and hold effect as I am in the same situation studying the example code, but finding it difficult to understand

[Kenneth]

Hello,

For new development you should be using the nRF Connect SDK that have a very different implementation. Something like this example show: 
https://github.com/martelmy/NCS_examples/tree/main/peripherals/long_press_button 

To get familiar with nRF Connect SDK: https://academy.nordicsemi.com/ 

In any case, this post if 4 years old, so I am closing it.

Kenneth