add 2 exemples for communication between to esp32

examples/client_receive_send_from_to_server/client_receive_send_from_to_server.ino

@@ -0,0 +1,135 @@
+#include <BLEDevice.h>
+
+std::string rxValue;
+String rxValueArduino ="";
+static BLEUUID SERVICE_UUID("6E400001-B5A3-F393-E0A9-E50E24DCCA9E");
+static BLEUUID    CHARACTERISTIC_UUID_RX("6E400003-B5A3-F393-E0A9-E50E24DCCA9E");
+static BLEUUID    CHARACTERISTIC_UUID_TX("6E400002-B5A3-F393-E0A9-E50E24DCCA9E");
+static BLEAddress *pServerAddress;
+static boolean doConnect = false;
+static boolean deviceConnected = false;
+static BLERemoteCharacteristic* pRemoteCharacteristic;
+
+BLERemoteService* pRemoteService;
+//static void notifyCallback(
+//BLERemoteCharacteristic* pBLERemoteCharacteristic,
+//uint8_t* pData,
+//size_t length,
+//bool isNotify) {
+//Serial.print("Notify callback for characteristic ");
+//Serial.print(pBLERemoteCharacteristic->getUUID().toString().c_str());
+//}
+
+bool connectToServer(BLEAddress pAddress) {
+  Serial.print("Forming a connection to ");
+  Serial.println(pAddress.toString().c_str());
+  BLEClient*  pClient  = BLEDevice::createClient();
+  pClient->connect(pAddress);
+  Serial.println(" - Connected to server");
+  pRemoteService = pClient->getService(SERVICE_UUID);
+  if (pRemoteService == nullptr) {
+    Serial.print("Failed to find our service UUID: ");
+    Serial.println(SERVICE_UUID.toString().c_str());
+    return false;
+  }
+
+  Serial.println(" - Found our service");
+
+  // Obtain a reference to the characteristic in the service of the remote BLE server.
+  //pRemoteCharacteristic = pRemoteService->getCharacteristic(CHARACTERISTIC_UUID_RX);
+  //if (pRemoteCharacteristic == nullptr) {
+  //Serial.print("Failed to find our characteristic UUID: ");
+  //Serial.println(CHARACTERISTIC_UUID_RX.toString().c_str());
+  //return false;
+  //}
+  //Serial.println(" - Found our characteristic");
+  // Read the value of the characteristic.
+  //pRemoteCharacteristic->registerForNotify(notifyCallback);
+}
+
+class MyAdvertisedDeviceCallbacks: 
+public BLEAdvertisedDeviceCallbacks {
+  void onResult(BLEAdvertisedDevice advertisedDevice) {
+    Serial.print("BLE Advertised Device found: ");
+    Serial.println(advertisedDevice.toString().c_str());
+    if (advertisedDevice.haveServiceUUID() && advertisedDevice.getServiceUUID().equals(SERVICE_UUID)) {
+      Serial.print("Found our device!  address: ");
+      advertisedDevice.getScan()->stop();
+      pServerAddress = new BLEAddress(advertisedDevice.getAddress());
+      doConnect = true;
+    }
+  }
+
+};
+
+String txStringArduino ="";
+String getValue(String data, char separator, int index)
+{
+  int found = 0;
+  int strIndex[] = { 
+    0, -1   };
+  int maxIndex = data.length() - 1;
+  for (int i = 0; i <= maxIndex && found <= index; i++) {
+    if (data.charAt(i) == separator || i == maxIndex) {
+      found++;
+      strIndex[0] = strIndex[1] + 1;
+      strIndex[1] = (i == maxIndex) ? i+1 : i;
+    }
+  }
+  return found > index ? data.substring(strIndex[0], strIndex[1]) : "";
+}
+
+
+void setup()
+{
+  BLEDevice::init("ESP32");
+  BLEScan* pBLEScan = BLEDevice::getScan();
+  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());
+  pBLEScan->setActiveScan(true);
+  pBLEScan->start(30);
+
+  Serial.begin(9600);
+}
+
+void loop()
+{
+  delay(20);
+  if (doConnect == true) {
+    if (connectToServer(*pServerAddress)) {
+      Serial.println("We are now connected to the BLE Server.");
+      deviceConnected = true;
+    } 
+    else {
+      Serial.println("We have failed to connect to the server; there is nothin more we will do.");
+    }
+    doConnect = false;
+  }
+  if (deviceConnected) {
+    pRemoteCharacteristic = pRemoteService->getCharacteristic(CHARACTERISTIC_UUID_RX);
+    rxValue = pRemoteCharacteristic->readValue();
+    rxValueArduino ="";
+    for (int i = 0; i < rxValue.length(); i++) {
+      rxValueArduino += rxValue[i];
+    }
+  }
+
+  txStringArduino += String(	random( 80 , 90 )) +'|';
+  txStringArduino += String(	random( 100 , 110 )) +'|';
+  txStringArduino += String(	random( 110 , 120 )) +'|';
+  txStringArduino += String(	random( 120 , 130 )) +'|';
+  if (deviceConnected) {
+    pRemoteCharacteristic = pRemoteService->getCharacteristic(CHARACTERISTIC_UUID_TX);
+    pRemoteCharacteristic->writeValue(txStringArduino.c_str() ,txStringArduino.length() );
+  }
+  txStringArduino ="";
+  Serial.print(getValue(rxValueArduino,'|', 0).toInt());
+  Serial.print(" ");
+  Serial.print(getValue(rxValueArduino,'|', 1).toInt());
+  Serial.print(" ");
+  Serial.print(getValue(rxValueArduino,'|', 2).toInt());
+  Serial.print(" ");
+  Serial.print(getValue(rxValueArduino,'|', 3).toInt());
+  Serial.print(" ");
+  Serial.println();
+}
+

examples/server_receive_send_from_to client/server_receive_send_from_to client.ino

@@ -0,0 +1,112 @@
+#include <BLEDevice.h>
+#include <BLEServer.h>
+#include <BLEUtils.h>
+#include <BLE2902.h>
+
+BLECharacteristic *pCharacteristic;
+std::string rxValue;
+String rxValueArduino ="";
+bool deviceConnected = false;
+#define SERVICE_UUID           "6E400001-B5A3-F393-E0A9-E50E24DCCA9E" // UART service UUID
+#define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"
+#define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"
+class MyServerCallbacks: 
+public BLEServerCallbacks {
+  void onConnect(BLEServer* pServer) {
+    deviceConnected = true;
+  };
+
+
+  void onDisconnect(BLEServer* pServer) {
+    deviceConnected = false;
+  }
+};
+class MyCallbacks: 
+public BLECharacteristicCallbacks {
+  void onWrite(BLECharacteristic *pCharacteristic) {
+    rxValue = pCharacteristic->getValue();
+    rxValueArduino ="";
+    for (int i = 0; i < rxValue.length(); i++) {
+      rxValueArduino += rxValue[i];
+    }
+  }
+};
+String txStringArduino ="";
+String getValue(String data, char separator, int index)
+{
+  int found = 0;
+  int strIndex[] = { 
+    0, -1   };
+  int maxIndex = data.length() - 1;
+  for (int i = 0; i <= maxIndex && found <= index; i++) {
+    if (data.charAt(i) == separator || i == maxIndex) {
+      found++;
+      strIndex[0] = strIndex[1] + 1;
+      strIndex[1] = (i == maxIndex) ? i+1 : i;
+    }
+  }
+  return found > index ? data.substring(strIndex[0], strIndex[1]) : "";
+}
+
+
+void setup()
+{
+  BLEDevice::init("ESP32");
+  // Create the BLE Server
+  BLEServer *pServer = BLEDevice::createServer();
+  pServer->setCallbacks(new MyServerCallbacks());
+
+  // Create the BLE Service
+  BLEService *pService = pServer->createService(SERVICE_UUID);
+
+  // Create a BLE Characteristic
+  pCharacteristic = pService->createCharacteristic(
+  CHARACTERISTIC_UUID_TX,
+  BLECharacteristic::PROPERTY_NOTIFY
+    );
+
+  pCharacteristic->addDescriptor(new BLE2902());
+
+  BLECharacteristic *pCharacteristic = pService->createCharacteristic(
+  CHARACTERISTIC_UUID_RX,
+  BLECharacteristic::PROPERTY_WRITE
+    );
+  pCharacteristic->setCallbacks(new MyCallbacks());
+  // Start the service
+  pService->start();
+
+  // Start advertising
+  BLEAdvertising *pAdvertising = pServer->getAdvertising();
+  pAdvertising->addServiceUUID(pService->getUUID());
+  pAdvertising->start();
+  Serial.println("Waiting a client connection to notify...");
+  Serial.begin(9600);
+}
+
+void loop()
+{
+  txStringArduino += String(	random( 0 , 10 )) +'|';
+  txStringArduino += String(	random( 20 , 30 )) +'|';
+  txStringArduino += String(	random( 40 , 50 )) +'|';
+  txStringArduino += String(	random( 60 , 70 )) +'|';
+  if (deviceConnected) {
+    uint8_t txLen = txStringArduino.length();
+    char txString[ txLen ];
+    for(uint8_t i=0; i<txLen; i++){
+      txString[i] = txStringArduino[i];
+    }
+    pCharacteristic->setValue(txString);
+    pCharacteristic->notify(); // Send the value to the app!
+  }
+  txStringArduino ="";
+  Serial.print(getValue(rxValueArduino,'|', 0).toInt());
+  Serial.print(" ");
+  Serial.print(getValue(rxValueArduino,'|', 1).toInt());
+  Serial.print(" ");
+  Serial.print(getValue(rxValueArduino,'|', 2).toInt());
+  Serial.print(" ");
+  Serial.print(getValue(rxValueArduino,'|', 3).toInt());
+  Serial.print(" ");
+  Serial.println();
+}
+