ESP32 BLE multiple servers one client

Hello! I have been working on connecting one BLE client ESP32 to two ESP32 servers connected to BNO055 9DOF sensors. So far, I have been able to do a one to one connection and received the orientation and acceleration data. I'm not exactly sure how to adjust my code to account for another server connection. Would there be a way to only stop scanning once both servers are connected? Or is there a way to manually control connections and disconnections? Any tips or advice is appreciated

OCClient.ino (6.4 KB)
OCServer.ino (6.4 KB)

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Hello !
Same project as you, I need to connect one client BLE ESP32 to 5 devices (BLE server) simultaneously (with notification activated)
I found a post https://esp32.com/viewtopic.php?t=11745 but it doesn't work
If someone could share his method, it will be great !
Regards

I manage to connect 3 BLE servers to 1 Client but no more...
No effet after changing the CONFIG_BTDM_CONTROLLER_BLE_MAX_CONN and CONFIG_BTDM_CONTROLLER_BLE_MAX_CONN_EFF from 5 to 3 in sdkconfig.h
at C:\Users\MyName\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.4\tools\sdk\include\config.


#include "BLEDevice.h"

// #define DEBUG

int MaxDevice = 3;
int CountDevice = 0;

String ConnectedDevices[5];
String ScannedBLEAddress[5];
static BLEAddress *ServerBLEAddress[5];
static BLEAdvertisedDevice *ServerBLE[5];

// Struct definition.
struct Array3 {
    int array[3];
};

#define SERVICE_UUID           "6E400001-B5A3-F393-E0A9-E50E24DCCA9E" // UART service UUID
#define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E" // RX Characteristic
#define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E" // TX Characteristic
static BLEUUID serviceUUID(SERVICE_UUID);
static BLEUUID charUUID_RX(CHARACTERISTIC_UUID_RX);   
static BLEUUID charUUID_TX(CHARACTERISTIC_UUID_TX);  

static boolean doConnect = false;
static boolean connected = false;
static boolean doScan = false;
static BLERemoteCharacteristic* pTXCharacteristic;
static BLERemoteCharacteristic* pRXCharacteristic;
static BLEAdvertisedDevice* myDevice;

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());
    Serial.print(" of data length ");
    Serial.println(length);
    Serial.print("data: ");
    Serial.println((char*)pData);
    */
    
    #ifdef DEBUG
    Serial.print((char*)pData);
    Serial.println("");
    Serial.print("HEX: ");
    printHex(pData, sizeof(pData));
    Serial.println("");
    Serial.print("DEC: ");
    printDec(pData, sizeof(pData));
    Serial.println("");
    #endif
    ParseMessage(pData);
}

class MyClientCallback : public BLEClientCallbacks {
  void onConnect(BLEClient* pclient) {
    //CountDevice +=1;
    //ConnectedDevices[CountDevice]= myDevice->getAddress().toString().c_str();
    Serial.printf("CountConnectedDevice = %i\n", CountDevice);

  }

  void onDisconnect(BLEClient* pclient) {
    connected = false;
    Serial.println("onDisconnect");
    //CountDevice -=1;
  }
};

bool connectToServer() {
    Serial.print("Forming a connection to ");
    //Serial.println(myDevice->getAddress().toString().c_str());
    Serial.println(ServerBLE[CountDevice]->getAddress().toString().c_str());
    BLEClient*  pClient  = BLEDevice::createClient();
    Serial.println(" - Created client");

    pClient->setClientCallbacks(new MyClientCallback());

    // Connect to the remove BLE Server.
    //pClient->connect(myDevice);  
     pClient->connect(ServerBLE[CountDevice]);
    // if you pass BLEAdvertisedDevice instead of address, 
    // it will be recognized type of peer device address (public or private)
    Serial.println(" - Connected to server");

    // Obtain a reference to the service we are after in the remote BLE server.
    BLERemoteService* pRemoteService = pClient->getService(serviceUUID);
    if (pRemoteService == nullptr) {
      Serial.print("Failed to find our service UUID: ");
      Serial.println(serviceUUID.toString().c_str());
      pClient->disconnect();
      return false;
    }
    Serial.println(" - Found our service");

    // ======================================================
    // Obtain a reference to the characteristic in the service of the remote BLE server.
    // charUUID_TX
    pTXCharacteristic = pRemoteService->getCharacteristic(charUUID_TX);
    if (pTXCharacteristic == nullptr) {
      Serial.print("Failed to find our characteristic UUID: ");
      Serial.println(charUUID_TX.toString().c_str());
      pClient->disconnect();
      return false;
    }
    Serial.println(" - Found charUUID_TX characteristic");

    // Read the value of the characteristic.
    if(pTXCharacteristic->canRead()) {
      std::string value = pTXCharacteristic->readValue();
      Serial.print("The characteristic value was: ");
      Serial.println(value.c_str());
    }

    if(pTXCharacteristic->canNotify())
      pTXCharacteristic->registerForNotify(notifyCallback);

    // ======================================================
    // Obtain a reference to the characteristic in the service of the remote BLE server.
    // charUUID_RX
    pRXCharacteristic = pRemoteService->getCharacteristic(charUUID_RX);
    if (pRXCharacteristic == nullptr) {
      Serial.print("Failed to find our characteristic UUID: ");
      Serial.println(charUUID_RX.toString().c_str());
      pClient->disconnect();
      return false;
    }
    Serial.println(" - Found charUUID_RX characteristic");

    //String helloValue = "Hello Remote Server";
    //pRXCharacteristic->writeValue(helloValue.c_str(), helloValue.length());

    // ======================================================
    connected = true;
    return true;
}

/**
 * Scan for BLE servers and find the first one that 
 * advertises the service we are looking for.
 */
class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {
 /**
   * Called for each advertising BLE server.
   */
  void onResult(BLEAdvertisedDevice advertisedDevice) {
    Serial.print("BLE Advertised Device found: ");
    Serial.println(advertisedDevice.toString().c_str());

    // We have found a device, 
    // let us now see if it contains the service we are looking for.

   // if (strcmp(advertisedDevice.getAddress().toString().c_str(), "e8:57:57:05:a5:bd")==0) // ConnectedDevices[CountDevice]
   // if (strcmp(advertisedDevice.getAddress().toString().c_str(), ConnectedDevices[CountDevice].c_str())==0) // ConnectedDevices[CountDevice]    
   // {
    if (advertisedDevice.haveServiceUUID() && 
      advertisedDevice.isAdvertisingService(serviceUUID)) {

      //BLEDevice::getScan()->stop();
      myDevice = new BLEAdvertisedDevice(advertisedDevice);
      ServerBLE[CountDevice] = myDevice;
      /*
      ServerBLEAddress[CountDevice] =  new BLEAddress(advertisedDevice.getAddress());
      ScannedBLEAddress[CountDevice] = ServerBLEAddress->toString().c_str();
      */
      doConnect = true;
      doScan = true;
      CountDevice +=1;
    } // Found our server
   // } // Found our address
  } // onResult
}; // MyAdvertisedDeviceCallbacks


void setup() {
  Serial.begin(115200);
  Serial.println("Starting Arduino BLE Client application...");
  BLEDevice::init("");

  // Retrieve a Scanner and set the callback we want to use to be informed when we
  // have detected a new device.  Specify that we want active scanning and start the
  // scan to run for 5 seconds.
  BLEScan* pBLEScan = BLEDevice::getScan();
  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());
  pBLEScan->setInterval(100); //1349
  pBLEScan->setWindow(99); //499
  pBLEScan->setActiveScan(true);
  BLEScanResults foundDevices =pBLEScan->start(3, false); // 5,false
    Serial.printf("foundDevices.getCount()= %i \n",foundDevices.getCount());
    for(int i=0;i<foundDevices.getCount();i++) {
    BLEAdvertisedDevice res = foundDevices.getDevice(i);
    Serial.print(res.getName().c_str());
    Serial.print(" @ ");
    Serial.println(res.getAddress().toString().c_str());
    ConnectedDevices[i]= res.getAddress().toString().c_str();
    /*
    MyClient* pMyClient = new MyClient();
    pMyClient->setStackSize(5000);
    pMyClient->start(new BLEAddress(*res.getAddress().getNative()));
    vTaskDelay(100);
    */
  }
      CountDevice=0;

} // End of setup.


// This is the Arduino main loop function.
void loop() {

  // If the flag "doConnect" is true then we have scanned for and found the desired
  // BLE Server with which we wish to connect.  Now we connect to it.  Once we are 
  // connected we set the connected flag to be true.
  if (doConnect == true) {
     //Serial.println(ConnectedDevices[CountDevice].getAddress().toString().c_str());
     Serial.printf("CountDevice = %i\n",  CountDevice);
     Serial.println(ServerBLE[CountDevice]->getAddress().toString().c_str());
     Serial.println(ServerBLE[CountDevice]->getName().c_str());
    //  if (connectToServerByMAC(*ServerBLE)) { //ConnectedDevices[CountDevice].getAddress()
      if (connectToServer()) {
        Serial.println("We are now connected to the BLE Server.");
        CountDevice +=1;  
      } else {
        Serial.println("We have failed to connect to the server; there is nothin more we will do.");
         CountDevice +=1;  
      }
      if (CountDevice >= MaxDevice)
      {
        doConnect = false;
      }
     
//     } //ENDIF ScannedBLEAddress
  } //ENDif doConnect

  // If we are connected to a peer BLE Server, 
  // update the characteristic each time we are reached
  // with the current time since boot.
  if (connected) {
    //String newValue = "Time since boot: " + String(millis()/1000 + "\n");
    //Serial.println("Setting new characteristic value to \"" + newValue + "\"");

/*
    String newValue = " " + String(millis()/1000);
    // Set the characteristic's value to be the array of bytes that is actually a string.
    pRXCharacteristic->writeValue(newValue.c_str(), newValue.length());
*/

/*
     //uint8_t SET_LED_i[] = {8,255,255,255};
     uint8_t SET_LED_i[] = {8,0,0,0};
     pRXCharacteristic->writeValue(SET_LED_i, sizeof(SET_LED_i)); //SET_LED 8

      uint8_t BATTERY_LEVEL_i = 3;
      pRXCharacteristic->writeValue(BATTERY_LEVEL_i, sizeof(BATTERY_LEVEL_i)); //BATTERY_LEVEL 3
  */
    
  }else if(doScan){
    BLEDevice::getScan()->start(0);  //start(0)
    // this is just example to start scan after disconnect, 
    // most likely there is better way to do it in arduino
  }
  
  delay(1000); // Delay a second between loops.
} // End of loop

void printHex(byte *buffer, byte bufferSize) {
 for (byte i = 0; i < bufferSize; i++) {
   Serial.print(buffer[i] < 0x10 ? " 0" : " ");
   Serial.print(buffer[i], HEX);
 }
}
/**
   Helper routine to dump a byte array as dec values to Serial.
*/
void printDec(byte *buffer, byte bufferSize) {
 for (byte i = 0; i < bufferSize; i++) {
   Serial.print(buffer[i] < 0x10 ? " 0" : " ");
   Serial.print(buffer[i], DEC);
 }
}

void ParseMessage(byte *data)
{
// Get a message and fire the matchig event 
}

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