BLE using ESP 32 - c++

Question

I am trying to program a BLE client using an ESP32. I have used the attached code (which is the example code from the example section). My problem right now is, how do I get it to show the MAC address of the scanned device only, and how do I change this MAC address into a JSON format for a LoRa chip to transmit? Thank you so much for your time to read this post.
/*
Based on Neil Kolban example for IDF: https://github.com/nkolban/esp32-snippets/blob/master/cpp_utils/tests/BLE%20Tests/SampleScan.cpp
Ported to Arduino ESP32 by Evandro Copercini
*/
#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>
int scanTime = 5; //In seconds
BLEScan* pBLEScan;
class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {
void onResult(BLEAdvertisedDevice advertisedDevice) {
Serial.printf("Advertised Device: %s \n", advertisedDevice.toString().c_str());
}
};
void setup() {
Serial.begin(115200);
Serial.println("Scanning...");
BLEDevice::init("");
pBLEScan = BLEDevice::getScan(); //create new scan
pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());
pBLEScan->setActiveScan(true); //active scan uses more power, but get results faster
pBLEScan->setInterval(100);
pBLEScan->setWindow(99); // less or equal setInterval value
}
void loop() {
// put your main code here, to run repeatedly:
BLEScanResults foundDevices = pBLEScan->start(scanTime, false);
Serial.print("Devices found: ");
Serial.println(foundDevices.getCount());
Serial.println("Scan done!");
pBLEScan->clearResults(); // delete results fromBLEScan buffer to release memory
delay(2000);
}

Answer 1

The result of your scan is foundDevices, which contains a list of all found devices. We can iterate through it to access the devices. The List contains BLEAdvertisedDevices which have a method called getAddress(). The address can be converted to a string using toString(). You can print the string or put it into your json container.
Your loop-code could look like this:
void loop() {
// put your main code here, to run repeatedly:
BLEScanResults foundDevices = pBLEScan->start(scanTime, false);
Serial.print("Devices found: ");
for (int i = 0; i < foundDevices.getCount(); ++i)
{
std::string address = foundDevices.getDevice(i).getAddress().toString();
int rssi = foundDevices.getDevice(i).getRSSI();
Serial.print(address.c_str());
Serial.print(rssi);
// TODO: Insert into JSON
}
Serial.println(foundDevices.getCount());
Serial.println("Scan done!");
pBLEScan->clearResults(); // delete results fromBLEScan buffer to release memory
delay(2000);
}