github.com/arduino-libraries/Keyboard/pull/61

Author: Cemu0

BleKeyboard.cpp

@@ -470,6 +470,11 @@ void BleKeyboard::releaseAll(void)
 	sendReport(&_keyReport);
 }
 
+bool BleKeyboard::getLedStatus(uint8_t led)
+{
+	return ((_keyboardLedsStatus & led)!=0);    
+}
+
 size_t BleKeyboard::write(uint8_t c)
 {
 	uint8_t p = press(c);  // Keydown
@@ -531,6 +536,7 @@ void BleKeyboard::onDisconnect(BLEServer* pServer) {
 void BleKeyboard::onWrite(BLECharacteristic* me) {
   uint8_t* value = (uint8_t*)(me->getValue().c_str());
   (void)value;
+  _keyboardLedsStatus = *value;
   ESP_LOGI(LOG_TAG, "special keys: %d", *value);
 }
 

BleKeyboard.h

@@ -100,6 +100,10 @@ const uint8_t KEY_NUM_PLUS = 0xDF;
 const uint8_t KEY_NUM_ENTER = 0xE0;
 const uint8_t KEY_NUM_PERIOD = 0xEB;
 
+const uint8_t LED_CAPS_LOCK = 0x02;
+const uint8_t LED_NUM_LOCK = 0x01;
+const uint8_t LED_SCROLL_LOCK = 0x04;
+
 typedef uint8_t MediaKeyReport[2];
 
 const MediaKeyReport KEY_MEDIA_NEXT_TRACK = {1, 0};
@@ -140,6 +144,7 @@ class BleKeyboard : public Print, public BLEServerCallbacks, public BLECharacter
   MediaKeyReport     _mediaKeyReport;
   std::string        deviceName;
   std::string        deviceManufacturer;
+  uint8_t _keyboardLedsStatus;
   uint8_t            batteryLevel;
   bool               connected = false;
   uint32_t           _delay_ms = 7;
@@ -163,6 +168,7 @@ class BleKeyboard : public Print, public BLEServerCallbacks, public BLECharacter
   size_t write(const MediaKeyReport c);
   size_t write(const uint8_t *buffer, size_t size);
   void releaseAll(void);
+  bool getLedStatus(uint8_t led);
   bool isConnected(void);
   void setBatteryLevel(uint8_t level);
   void setName(std::string deviceName);