Finished with prototyping pCharacteristic communication

src/lightingFirmware/SimpleBleDevice/SimpleBleDevice.ino

@@ -1,6 +1,14 @@
 #include <BLEDevice.h>
-#include <BLEUtils.h>
 #include <BLEServer.h>
+#include <BLEUtils.h>
+#include <BLE2902.h>
+ 
+BLEServer* pServer = NULL;
+BLECharacteristic* pCharacteristic = NULL;
+bool deviceConnected = false;
+bool oldDeviceConnected = false;
+uint32_t value = 0;
+String btmessage;
  
 // See the following for generating UUIDs:
 // https://www.uuidgenerator.net/
@@ -8,32 +16,74 @@
 #define SERVICE_UUID        "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
 #define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"
  
+ 
+class MyServerCallbacks: public BLEServerCallbacks {
+    void onConnect(BLEServer* pServer) {
+      deviceConnected = true;
+    };
+ 
+    void onDisconnect(BLEServer* pServer) {
+      deviceConnected = false;
+    }
+};
+ 
+ 
+ 
 void setup() {
   Serial.begin(115200);
-  Serial.println("Starting BLE work!");
  
-  BLEDevice::init("Long name works now");
-  BLEServer *pServer = BLEDevice::createServer();
+  // Create the BLE Device
+  BLEDevice::init("ESP32");
+ 
+  // Create the BLE Server
+  pServer = BLEDevice::createServer();
+  pServer->setCallbacks(new MyServerCallbacks());
+ 
+  // Create the BLE Service
   BLEService *pService = pServer->createService(SERVICE_UUID);
-  BLECharacteristic *pCharacteristic = pService->createCharacteristic(
-                                         CHARACTERISTIC_UUID,
-                                         BLECharacteristic::PROPERTY_READ |
-                                         BLECharacteristic::PROPERTY_WRITE
-                                       );
  
-  pCharacteristic->setValue("Hello World says Neil");
+  // Create a BLE Characteristic
+  pCharacteristic = pService->createCharacteristic(
+                      CHARACTERISTIC_UUID,
+                      BLECharacteristic::PROPERTY_READ   |
+                      BLECharacteristic::PROPERTY_WRITE  |
+                      BLECharacteristic::PROPERTY_NOTIFY |
+                      BLECharacteristic::PROPERTY_INDICATE
+                    );
+ 
+  // https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.descriptor.gatt.client_characteristic_configuration.xml
+  // Create a BLE Descriptor
+  pCharacteristic->addDescriptor(new BLE2902());
+ 
+  // Start the service
   pService->start();
-  // BLEAdvertising *pAdvertising = pServer->getAdvertising();  // this still is working for backward compatibility
+ 
+  // Start advertising
   BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
   pAdvertising->addServiceUUID(SERVICE_UUID);
-  pAdvertising->setScanResponse(true);
-  pAdvertising->setMinPreferred(0x06);  // functions that help with iPhone connections issue
-  pAdvertising->setMinPreferred(0x12);
+  pAdvertising->setScanResponse(false);
+  pAdvertising->setMinPreferred(0x0);  // set value to 0x00 to not advertise this parameter
   BLEDevice::startAdvertising();
-  Serial.println("Characteristic defined! Now you can read it in your phone!");
+  Serial.println("Waiting a client connection to notify...");
 }
 
 void loop() {
-  // put your main code here, to run repeatedly:
-  delay(2000);
+    // notify changed value
+    if (deviceConnected) {
+        btmessage = pCharacteristic->getValue().c_str();
+        Serial.print(btmessage);
+        delay(1000); // bluetooth stack will go into congestion, if too many packets are sent, in 6 hours test i was able to go as low as 3ms
+    }
+    // disconnecting
+    if (!deviceConnected && oldDeviceConnected) {
+        delay(500); // give the bluetooth stack the chance to get things ready
+        pServer->startAdvertising(); // restart advertising
+        Serial.println("Start advertising");
+        oldDeviceConnected = deviceConnected;
+    }
+    // connecting
+    if (deviceConnected && !oldDeviceConnected) {
+        // do stuff here on connecting
+        oldDeviceConnected = deviceConnected;
+    }
 }

src/lightingFirmware/esp32_test0/esp32_test0.ino

@@ -35,7 +35,7 @@ struct Panel {
   int led0;
   int led1;
   int led2;
-  int led3;
+  int led3 = 0;
 };
 
 
@@ -262,27 +262,28 @@ void setup() {
 	pinMode(INTERRUPT_PIN, INPUT_PULLUP);
 	attachInterrupt(digitalPinToInterrupt(INTERRUPT_PIN), isr, RISING);
   delay(2000);
-  Serial.println("If you receive this message, ESP32 module has finished setting up Serial Interface for communication.");
+  Serial.print("\nIf you receive this message, ESP32 module has finished setting up Serial Interface for communication.");
   dmxSetup();
   const dmx_port_t dmx_num = DMX_NUM_1;
 }
 
 void loop() {
   // Send the DMX packet.
+  int modeOld = mode;
+  serialRead();
   dmx_send(DMX_NUM_1);
   // Preparing next packet
   if (button1.pressed){  
     if (mode < modeAmount - 1){mode++;} else {mode = 0;};
-    Serial.printf("\nChanging to mode %d", mode);  // Increment the value of each slot, excluding the start code.
+    // Increment the value of each slot, excluding the start code.
     button1.pressed = false; // Reset button status to FALSE
   };
+  if (modeOld != mode){
+    Serial.printf("\nChanging Lighting Preset to Preset %d", mode);
+  }
   // Wait until the packet is finished being sent before proceeding.
   dmx_wait_sent(DMX_NUM_1, DMX_TIMEOUT_TICK);
   // Now write the packet synchronously!
   dmx_write(DMX_NUM_1, dataSeq[mode], 100);
   serialRead();
-  if (SerialBT.available()) {
-   btmessage=SerialBT.read();
-   Serial.print(btmessage);
-  };
 }