ESP32 Forum

Hi, TEAM,
i'm working on project where multiple devices need to connect to server, & for my use, Server need to know exactly which devices got disconnect by any reason (power down or whatever) ,
i tried to get mac address of connected client but couldn't get it



#include <BLEDevice.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;

// See the following for generating UUIDs:
// https://www.uuidgenerator.net/

#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;
BLEDevice::startAdvertising();
};

void onDisconnect(BLEServer* pServer) {
deviceConnected = false;
}
};



void setup() {
Serial.begin(115200);

// 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);

// 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/specification ... ration.xml
// Create a BLE Descriptor
pCharacteristic->addDescriptor(new BLE2902());

// Start the service
pService->start();

// Start advertising
BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
pAdvertising->addServiceUUID(SERVICE_UUID);
pAdvertising->setScanResponse(false);
pAdvertising->setMinPreferred(0x0); // set value to 0x00 to not advertise this parameter
BLEDevice::startAdvertising();
Serial.println("Waiting a client connection to notify...");
}

void loop() {
// notify changed value
if (deviceConnected) {
pCharacteristic->setValue((uint8_t*)&value, 4);
pCharacteristic->notify();
value++;
delay(10); // 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;
}
}

Sure, you can get such info, im just not sure if this is enabled in arduino.
Thats why you have option to register custom callbacks.
Maybe on one callback you can get that info:
https://github.com/espressif/arduino-es ... #L127-L128