diff --git a/BleConnectionStatus.cpp b/BleConnectionStatus.cpp
deleted file mode 100644
index 1b8bcad..0000000
--- a/BleConnectionStatus.cpp
+++ /dev/null
@@ -1,25 +0,0 @@
-#include "BleConnectionStatus.h"
-
-BleConnectionStatus::BleConnectionStatus(void) {
-}
-
-void BleConnectionStatus::onConnect(BLEServer* pServer)
-{
-  this->connected = true;
-  BLE2902* desc = (BLE2902*)this->inputKeyboard->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
-  desc->setNotifications(true);
-
-  desc = (BLE2902*)this->inputMediaKeys->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
-  desc->setNotifications(true);
-}
-
-void BleConnectionStatus::onDisconnect(BLEServer* pServer)
-{
-  this->connected = false;
-  BLE2902* desc = (BLE2902*)this->inputKeyboard->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
-  desc->setNotifications(false);
-
-  desc = (BLE2902*)this->inputMediaKeys->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
-  desc->setNotifications(false);
-  pAdvertising->start();
-}
diff --git a/BleConnectionStatus.h b/BleConnectionStatus.h
deleted file mode 100644
index 67cd42a..0000000
--- a/BleConnectionStatus.h
+++ /dev/null
@@ -1,24 +0,0 @@
-#ifndef ESP32_BLE_CONNECTION_STATUS_H
-#define ESP32_BLE_CONNECTION_STATUS_H
-#include "sdkconfig.h"
-#if defined(CONFIG_BT_ENABLED)
-
-#include <BLEServer.h>
-#include "BLE2902.h"
-#include "BLECharacteristic.h"
-
-class BleConnectionStatus : public BLEServerCallbacks
-{
-public:
-  BleConnectionStatus(void);
-  bool connected = false;
-  void onConnect(BLEServer* pServer);
-  void onDisconnect(BLEServer* pServer);
-  BLECharacteristic* inputKeyboard;
-  BLECharacteristic* outputKeyboard;
-  BLECharacteristic* inputMediaKeys;
-  BLEAdvertising *pAdvertising;
-};
-
-#endif // CONFIG_BT_ENABLED
-#endif // ESP32_BLE_CONNECTION_STATUS_H
diff --git a/BleKeyboard.cpp b/BleKeyboard.cpp
index 007ce05..8b77b98 100644
--- a/BleKeyboard.cpp
+++ b/BleKeyboard.cpp
@@ -1,14 +1,19 @@
+#if defined(USE_NIMBLE)
+#include <NimBLEDevice.h>
+#include <NimBLEServer.h>
+#include <NimBLEUtils.h>
+#include <NimBLEHIDDevice.h>
+#else
 #include <BLEDevice.h>
 #include <BLEUtils.h>
 #include <BLEServer.h>
 #include "BLE2902.h"
 #include "BLEHIDDevice.h"
+#endif // USE_NIMBLE
 #include "HIDTypes.h"
 #include <driver/adc.h>
 #include "sdkconfig.h"
 
-#include "BleConnectionStatus.h"
-#include "KeyboardOutputCallbacks.h"
 #include "BleKeyboard.h"
 
 #if defined(CONFIG_ARDUHAL_ESP_LOG)
@@ -89,17 +94,47 @@ static const uint8_t _hidReportDescriptor[] = {
   END_COLLECTION(0)                  // END_COLLECTION
 };
 
-BleKeyboard::BleKeyboard(std::string deviceName, std::string deviceManufacturer, uint8_t batteryLevel) : hid(0)
-{
-  this->deviceName = deviceName;
-  this->deviceManufacturer = deviceManufacturer;
-  this->batteryLevel = batteryLevel;
-  this->connectionStatus = new BleConnectionStatus();
-}
+BleKeyboard::BleKeyboard(std::string deviceName, std::string deviceManufacturer, uint8_t batteryLevel) 
+    : hid(0)
+    , deviceName(std::string(deviceName).substr(0, 15))
+    , deviceManufacturer(std::string(deviceManufacturer).substr(0,15))
+    , batteryLevel(batteryLevel) {}
 
 void BleKeyboard::begin(void)
 {
-  xTaskCreate(this->taskServer, "server", 20000, (void *)this, 5, NULL);
+  BLEDevice::init(deviceName);
+  BLEServer* pServer = BLEDevice::createServer();
+  pServer->setCallbacks(this);
+
+  hid = new BLEHIDDevice(pServer);
+  inputKeyboard = hid->inputReport(KEYBOARD_ID);  // <-- input REPORTID from report map
+  outputKeyboard = hid->outputReport(KEYBOARD_ID);
+  inputMediaKeys = hid->inputReport(MEDIA_KEYS_ID);
+
+  outputKeyboard->setCallbacks(this);
+
+  hid->manufacturer()->setValue(deviceManufacturer);
+
+  hid->pnp(0x02, 0xe502, 0xa111, 0x0210);
+  hid->hidInfo(0x00, 0x01);
+
+  BLESecurity* pSecurity = new BLESecurity();
+
+  pSecurity->setAuthenticationMode(ESP_LE_AUTH_BOND);
+
+  hid->reportMap((uint8_t*)_hidReportDescriptor, sizeof(_hidReportDescriptor));
+  hid->startServices();
+
+  onStarted(pServer);
+
+  advertising = pServer->getAdvertising();
+  advertising->setAppearance(HID_KEYBOARD);
+  advertising->addServiceUUID(hid->hidService()->getUUID());
+  advertising->setScanResponse(false);
+  advertising->start();
+  hid->setBatteryLevel(batteryLevel);
+
+  ESP_LOGD(LOG_TAG, "Advertising started!");
 }
 
 void BleKeyboard::end(void)
@@ -107,7 +142,7 @@ void BleKeyboard::end(void)
 }
 
 bool BleKeyboard::isConnected(void) {
-  return this->connectionStatus->connected;
+  return this->connected;
 }
 
 void BleKeyboard::setBatteryLevel(uint8_t level) {
@@ -121,45 +156,13 @@ void BleKeyboard::setName(std::string deviceName) {
   this->deviceName = deviceName;
 }
 
-void BleKeyboard::taskServer(void* pvParameter) {
-  BleKeyboard* bleKeyboardInstance = (BleKeyboard *) pvParameter; //static_cast<BleKeyboard *>(pvParameter);
-  BLEDevice::init(bleKeyboardInstance->deviceName);
-  BLEServer *pServer = BLEDevice::createServer();
-  pServer->setCallbacks(bleKeyboardInstance->connectionStatus);
-
-  bleKeyboardInstance->hid = new BLEHIDDevice(pServer);
-  bleKeyboardInstance->inputKeyboard = bleKeyboardInstance->hid->inputReport(KEYBOARD_ID); // <-- input REPORTID from report map
-  bleKeyboardInstance->outputKeyboard = bleKeyboardInstance->hid->outputReport(KEYBOARD_ID);
-  bleKeyboardInstance->inputMediaKeys = bleKeyboardInstance->hid->inputReport(MEDIA_KEYS_ID);
-  bleKeyboardInstance->connectionStatus->inputKeyboard = bleKeyboardInstance->inputKeyboard;
-  bleKeyboardInstance->connectionStatus->outputKeyboard = bleKeyboardInstance->outputKeyboard;
-  bleKeyboardInstance->connectionStatus->inputMediaKeys = bleKeyboardInstance->inputMediaKeys;
-
-  bleKeyboardInstance->outputKeyboard->setCallbacks(new KeyboardOutputCallbacks());
-
-  bleKeyboardInstance->hid->manufacturer()->setValue(bleKeyboardInstance->deviceManufacturer);
-
-  bleKeyboardInstance->hid->pnp(0x02, 0xe502, 0xa111, 0x0210);
-  bleKeyboardInstance->hid->hidInfo(0x00,0x01);
-
-  BLESecurity *pSecurity = new BLESecurity();
-
-  pSecurity->setAuthenticationMode(ESP_LE_AUTH_BOND);
-
-  bleKeyboardInstance->hid->reportMap((uint8_t*)_hidReportDescriptor, sizeof(_hidReportDescriptor));
-  bleKeyboardInstance->hid->startServices();
-
-  bleKeyboardInstance->onStarted(pServer);
-
-  bleKeyboardInstance->connectionStatus->pAdvertising = pServer->getAdvertising();
-  bleKeyboardInstance->connectionStatus->pAdvertising->setAppearance(HID_KEYBOARD);
-  bleKeyboardInstance->connectionStatus->pAdvertising->addServiceUUID(bleKeyboardInstance->hid->hidService()->getUUID());
-  bleKeyboardInstance->connectionStatus->pAdvertising->setScanResponse(false);
-  bleKeyboardInstance->connectionStatus->pAdvertising->start();
-  bleKeyboardInstance->hid->setBatteryLevel(bleKeyboardInstance->batteryLevel);
-
-  ESP_LOGD(LOG_TAG, "Advertising started!");
-  vTaskDelay(portMAX_DELAY); //delay(portMAX_DELAY);
+/**
+ * @brief Sets the waiting time (in milliseconds) between multiple keystrokes in NimBLE mode.
+ * 
+ * @param ms Time in milliseconds
+ */
+void BleKeyboard::setDelay(uint32_t ms) {
+  this->_delay_ms = ms;
 }
 
 void BleKeyboard::sendReport(KeyReport* keys)
@@ -168,7 +171,11 @@ void BleKeyboard::sendReport(KeyReport* keys)
   {
     this->inputKeyboard->setValue((uint8_t*)keys, sizeof(KeyReport));
     this->inputKeyboard->notify();
-  }
+#if defined(USE_NIMBLE)        
+    // vTaskDelay(delayTicks);
+    this->delay_ms(_delay_ms);
+#endif // USE_NIMBLE
+  }	
 }
 
 void BleKeyboard::sendReport(MediaKeyReport* keys)
@@ -177,7 +184,11 @@ void BleKeyboard::sendReport(MediaKeyReport* keys)
   {
     this->inputMediaKeys->setValue((uint8_t*)keys, sizeof(MediaKeyReport));
     this->inputMediaKeys->notify();
-  }
+#if defined(USE_NIMBLE)        
+    //vTaskDelay(delayTicks);
+    this->delay_ms(_delay_ms);
+#endif // USE_NIMBLE
+  }	
 }
 
 extern
@@ -466,3 +477,31 @@ size_t BleKeyboard::write(const uint8_t *buffer, size_t size) {
 	}
 	return n;
 }
+
+void BleKeyboard::onConnect(BLEServer* pServer) {
+  this->connected = true;
+}
+
+void BleKeyboard::onDisconnect(BLEServer* pServer) {
+  this->connected = false;
+#if !defined(USE_NIMBLE)
+  advertising->start();
+#endif  // !USE_NIMBLE
+}
+
+void BleKeyboard::onWrite(BLECharacteristic* me) {
+  uint8_t* value = (uint8_t*)(me->getValue().c_str());
+  (void)value;
+  ESP_LOGI(LOG_TAG, "special keys: %d", *value);
+}
+
+void BleKeyboard::delay_ms(uint64_t ms) {
+  uint64_t m = esp_timer_get_time();
+  if(ms){
+    uint64_t e = (m + (ms * 1000));
+    if(m > e){ //overflow
+        while(esp_timer_get_time() > e) { }
+    }
+    while(esp_timer_get_time() < e) {}
+  }
+}
\ No newline at end of file
diff --git a/BleKeyboard.h b/BleKeyboard.h
index 678886d..4fdeaa5 100644
--- a/BleKeyboard.h
+++ b/BleKeyboard.h
@@ -3,9 +3,26 @@
 #include "sdkconfig.h"
 #if defined(CONFIG_BT_ENABLED)
 
-#include "BleConnectionStatus.h"
+#if defined(USE_NIMBLE)
+
+#include "NimBLECharacteristic.h"
+#include "NimBLEHIDDevice.h"
+
+#define BLEDevice                  NimBLEDevice
+#define BLEServerCallbacks         NimBLEServerCallbacks
+#define BLECharacteristicCallbacks NimBLECharacteristicCallbacks
+#define BLEHIDDevice               NimBLEHIDDevice
+#define BLECharacteristic          NimBLECharacteristic
+#define BLEAdvertising             NimBLEAdvertising
+#define BLEServer                  NimBLEServer
+
+#else
+
 #include "BLEHIDDevice.h"
 #include "BLECharacteristic.h"
+
+#endif // USE_NIMBLE
+
 #include "Print.h"
 
 
@@ -86,19 +103,25 @@ typedef struct
   uint8_t keys[6];
 } KeyReport;
 
-class BleKeyboard : public Print
+class BleKeyboard : public Print, public BLEServerCallbacks, public BLECharacteristicCallbacks
 {
 private:
-  BleConnectionStatus* connectionStatus;
   BLEHIDDevice* hid;
   BLECharacteristic* inputKeyboard;
   BLECharacteristic* outputKeyboard;
   BLECharacteristic* inputMediaKeys;
-  KeyReport _keyReport;
-  MediaKeyReport _mediaKeyReport;
-  static void taskServer(void* pvParameter);
+  BLEAdvertising*    advertising;
+  KeyReport          _keyReport;
+  MediaKeyReport     _mediaKeyReport;
+  std::string        deviceName;
+  std::string        deviceManufacturer;
+  uint8_t            batteryLevel;
+  bool               connected = false;
+  uint32_t           _delay_ms = 7;
+  void delay_ms(uint64_t ms);
+
 public:
-  BleKeyboard(std::string deviceName = "ESP32 BLE Keyboard", std::string deviceManufacturer = "Espressif", uint8_t batteryLevel = 100);
+  BleKeyboard(std::string deviceName = "ESP32 Keyboard", std::string deviceManufacturer = "Espressif", uint8_t batteryLevel = 100);
   void begin(void);
   void end(void);
   void sendReport(KeyReport* keys);
@@ -114,11 +137,13 @@ public:
   bool isConnected(void);
   void setBatteryLevel(uint8_t level);
   void setName(std::string deviceName);  
-  uint8_t batteryLevel;
-  std::string deviceManufacturer;
-  std::string deviceName;
+  void setDelay(uint32_t ms);
 protected:
   virtual void onStarted(BLEServer *pServer) { };
+  virtual void onConnect(BLEServer* pServer) override;
+  virtual void onDisconnect(BLEServer* pServer) override;
+  virtual void onWrite(BLECharacteristic* me) override;
+
 };
 
 #endif // CONFIG_BT_ENABLED
diff --git a/KeyboardOutputCallbacks.cpp b/KeyboardOutputCallbacks.cpp
deleted file mode 100644
index 286ce41..0000000
--- a/KeyboardOutputCallbacks.cpp
+++ /dev/null
@@ -1,18 +0,0 @@
-#include "KeyboardOutputCallbacks.h"
-
-#if defined(CONFIG_ARDUHAL_ESP_LOG)
-  #include "esp32-hal-log.h"
-  #define LOG_TAG ""
-#else
-  #include "esp_log.h"
-  static const char* LOG_TAG = "BLEDevice";
-#endif
-
-KeyboardOutputCallbacks::KeyboardOutputCallbacks(void) {
-}
-
-void KeyboardOutputCallbacks::onWrite(BLECharacteristic* me) {
-  uint8_t* value = (uint8_t*)(me->getValue().c_str());
-  ESP_LOGI(LOG_TAG, "special keys: %d", *value);
-}
-
diff --git a/KeyboardOutputCallbacks.h b/KeyboardOutputCallbacks.h
deleted file mode 100644
index bce158e..0000000
--- a/KeyboardOutputCallbacks.h
+++ /dev/null
@@ -1,18 +0,0 @@
-#ifndef ESP32_BLE_KEYBOARD_OUTPUT_CALLBACKS_H
-#define ESP32_BLE_KEYBOARD_OUTPUT_CALLBACKS_H
-#include "sdkconfig.h"
-#if defined(CONFIG_BT_ENABLED)
-
-#include <BLEServer.h>
-#include "BLE2902.h"
-#include "BLECharacteristic.h"
-
-class KeyboardOutputCallbacks : public BLECharacteristicCallbacks
-{
-public:
-  KeyboardOutputCallbacks(void);
-  void onWrite(BLECharacteristic* me);
-};
-
-#endif // CONFIG_BT_ENABLED
-#endif // ESP32_BLE_KEYBOARD_OUTPUT_CALLBACKS_H
diff --git a/README.md b/README.md
index 44429e8..eb7ab98 100644
--- a/README.md
+++ b/README.md
@@ -105,6 +105,48 @@ Instead of `BleKeyboard bleKeyboard;` you can do `BleKeyboard bleKeyboard("Bluet
 The third parameter is the initial battery level of your device. To adjust the battery level later on you can simply call e.g.  `bleKeyboard.setBatteryLevel(50)` (set battery level to 50%).
 By default the battery level will be set to 100%, the device name will be `ESP32 Bluetooth Keyboard` and the manufacturer will be `Espressif`.
 
+## NimBLE-Mode
+The NimBLE mode enables a significant saving of RAM and FLASH memory.
+
+### Comparison (SendKeyStrokes.ino at compile-time)
+
+**Standard**
+```
+RAM:   [=         ]   9.3% (used 30548 bytes from 327680 bytes)
+Flash: [========  ]  75.8% (used 994120 bytes from 1310720 bytes)
+```
+
+**NimBLE mode**
+```
+RAM:   [=         ]   8.3% (used 27180 bytes from 327680 bytes)
+Flash: [====      ]  44.2% (used 579158 bytes from 1310720 bytes)
+```
+
+### Comparison (SendKeyStrokes.ino at run-time)
+
+|   | Standard | NimBLE mode | difference
+|---|--:|--:|--:|
+| `ESP.getHeapSize()`   | 296.804 | 321.252 | **+ 24.448**  |
+| `ESP.getFreeHeap()`   | 143.572 | 260.764 | **+ 117.192** |
+| `ESP.getSketchSize()` | 994.224 | 579.264 | **- 414.960** |
+
+### How to activate NimBLE mode?
+
+ArduinoIDE: Before including the library, insert the line `#define USE_NIMBLE`
+```C++
+#define USE_NIMBLE
+#include <BleKeyboard.h>
+```
+
+PlatformIO: Change your `platformio.ini` to the following settings
+```ini
+lib_deps = 
+  NimBLE-Arduino
+
+build-flags = 
+  -D USE_NIMBLE
+```
+
 ## Credits
 
 Credits to [chegewara](https://github.com/chegewara) and [the authors of the USB keyboard library](https://github.com/arduino-libraries/Keyboard/) as this project is heavily based on their work! Also, credits to [duke2421](https://github.com/T-vK/ESP32-BLE-Keyboard/issues/1) who helped a lot with testing, debugging and fixing the device descriptor!