Example of HID Keyboard BLE with ESP32

ESP32_HID.ino

/*
  Copyright (c) 2014-2020 Electronic Cats SAPI de CV.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>
#include "BLE2902.h"
#include "BLEHIDDevice.h"
#include "HIDTypes.h"
#include "HIDKeyboardTypes.h"
#include <driver/adc.h>

BLEHIDDevice* hid;
BLECharacteristic* input;
BLECharacteristic* output;

uint8_t buttons = 0;
uint8_t button1 = 0;
uint8_t button2 = 0;
uint8_t button3 = 0;
bool connected = false;

class MyCallbacks : public BLEServerCallbacks {
  void onConnect(BLEServer* pServer){
    connected = true;
    BLE2902* desc = (BLE2902*)input->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
    desc->setNotifications(true);
  }

  void onDisconnect(BLEServer* pServer){
    connected = false;
    BLE2902* desc = (BLE2902*)input->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
    desc->setNotifications(false);
  }
};

/*
 * This callback is connect with output report. In keyboard output report report special keys changes, like CAPSLOCK, NUMLOCK
 * We can add digital pins with LED to show status
 * bit 0 - NUM LOCK
 * bit 1 - CAPS LOCK
 * bit 2 - SCROLL LOCK
 */
 class MyOutputCallbacks : public BLECharacteristicCallbacks {
 void onWrite(BLECharacteristic* me){
    uint8_t* value = (uint8_t*)(me->getValue().c_str());
    ESP_LOGI(LOG_TAG, "special keys: %d", *value);
  }
};

void taskServer(void*){


    BLEDevice::init("Backpack-MeowMeow");
    BLEServer *pServer = BLEDevice::createServer();
    pServer->setCallbacks(new MyCallbacks());

    hid = new BLEHIDDevice(pServer);
    input = hid->inputReport(1); // <-- input REPORTID from report map
    output = hid->outputReport(1); // <-- output REPORTID from report map

    output->setCallbacks(new MyOutputCallbacks());

    std::string name = "ElectronicCats";
    hid->manufacturer()->setValue(name);

    hid->pnp(0x02, 0xe502, 0xa111, 0x0210);
    hid->hidInfo(0x00,0x02);

  BLESecurity *pSecurity = new BLESecurity();
//  pSecurity->setKeySize();
  pSecurity->setAuthenticationMode(ESP_LE_AUTH_BOND);

    const uint8_t report[] = {
      USAGE_PAGE(1),      0x01,       // Generic Desktop Ctrls
      USAGE(1),           0x06,       // Keyboard
      COLLECTION(1),      0x01,       // Application
      REPORT_ID(1),       0x01,        //   Report ID (1)
      USAGE_PAGE(1),      0x07,       //   Kbrd/Keypad
      USAGE_MINIMUM(1),   0xE0,
      USAGE_MAXIMUM(1),   0xE7,
      LOGICAL_MINIMUM(1), 0x00,
      LOGICAL_MAXIMUM(1), 0x01,
      REPORT_SIZE(1),     0x01,       //   1 byte (Modifier)
      REPORT_COUNT(1),    0x08,
      HIDINPUT(1),           0x02,       //   Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position
      REPORT_COUNT(1),    0x01,       //   1 byte (Reserved)
      REPORT_SIZE(1),     0x08,
      HIDINPUT(1),           0x01,       //   Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position
      REPORT_COUNT(1),    0x06,       //   6 bytes (Keys)
      REPORT_SIZE(1),     0x08,
      LOGICAL_MINIMUM(1), 0x00,
      LOGICAL_MAXIMUM(1), 0x65,       //   101 keys
      USAGE_MINIMUM(1),   0x00,
      USAGE_MAXIMUM(1),   0x65,
      HIDINPUT(1),           0x00,       //   Data,Array,Abs,No Wrap,Linear,Preferred State,No Null Position
      REPORT_COUNT(1),    0x05,       //   5 bits (Num lock, Caps lock, Scroll lock, Compose, Kana)
      REPORT_SIZE(1),     0x01,
      USAGE_PAGE(1),      0x08,       //   LEDs
      USAGE_MINIMUM(1),   0x01,       //   Num Lock
      USAGE_MAXIMUM(1),   0x05,       //   Kana
      HIDOUTPUT(1),          0x02,       //   Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile
      REPORT_COUNT(1),    0x01,       //   3 bits (Padding)
      REPORT_SIZE(1),     0x03,
      HIDOUTPUT(1),          0x01,       //   Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile
      END_COLLECTION(0)
    };

    hid->reportMap((uint8_t*)report, sizeof(report));
    hid->startServices();

    BLEAdvertising *pAdvertising = pServer->getAdvertising();
    pAdvertising->setAppearance(HID_KEYBOARD);
    pAdvertising->addServiceUUID(hid->hidService()->getUUID());
    pAdvertising->start();
    hid->setBatteryLevel(7);

    ESP_LOGD(LOG_TAG, "Advertising started!");
    delay(portMAX_DELAY);
  
};

void setup() {
  Serial.begin(115200);
  Serial.println("Starting BLE work!");

  pinMode(12, INPUT_PULLDOWN);
  attachInterrupt(digitalPinToInterrupt(12), clickNumLock, CHANGE);   // Num Lock
  pinMode(14, INPUT_PULLDOWN);
  attachInterrupt(digitalPinToInterrupt(13), clickCapsLock, CHANGE);   // Caps Lock
  pinMode(32, INPUT_PULLDOWN);
  attachInterrupt(digitalPinToInterrupt(32), clickScrollLock, CHANGE);   // Scroll Lock

  xTaskCreate(taskServer, "server", 20000, NULL, 5, NULL);
}

void loop() {
  
  if(connected){

    vTaskDelay(5000);
    const char* hello = "Hello world from esp32 hid keyboard!!!\n";

    while(*hello){
      KEYMAP map = keymap[(uint8_t)*hello];
      Serial.println(buttons);
      uint8_t msg[] = {map.modifier || buttons, 0x0, map.usage, 0x0,0x0,0x0,0x0,0x0};
      input->setValue(msg,sizeof(msg));
      input->notify();
      hello++;
      uint8_t msg1[] = {0x0, 0x0, 0x0, 0x0,0x0,0x0,0x0,0x0};

      input->setValue(msg1,sizeof(msg1));
      input->notify();
      delay(10);
    }
  }
  delay(50);
}

IRAM_ATTR void clickNumLock(){
  button1 = buttons&&0x01;
  button1 != button1;
  buttons = button1<<0;
}
IRAM_ATTR void clickCapsLock(){
  button2 = buttons&&0x02;
  button2 != button2;  
  buttons = button2<<1;
}
IRAM_ATTR void clickScrollLock(){
  button3 = buttons&&0x04;
  button3 != button3;  
  buttons = button3<<2;
}

Any idea why it sometimes prints out "HHHHHeeeeellllllllllooooo wwwwwooooorrrrrlllllddddd"...?

A # is missing in first line.

hola, tendras un ejemplo para simular un mouse?

Any idea why it sometimes prints out "HHHHHeeeeellllllllllooooo wwwwwooooorrrrrlllllddddd"...?

Probably you are not debouncing the push or mechanic switch, you can do that through two ways, width delays (not recomended) or a capacitor (each key) that will prevent the effect of the contact aproximation bounsing.