Help Subscribing to Probe Status Service by MAC Address

[flynace]

This is my first time trying to use NimBLE and an ESP32-S3.
I have a few probes and I know their MAC addresses and their Probe Status Service (UUID 00000100-CAAB-3792-3D44-97AE51C1407A) which has a single Service Characteristic (UUID 00000101-CAAB-3792-3D44-97AE51C1407A) that supports BLE notifications.

When I run the NimBLE_Client example sketch it sees a probe...
Advertised Device: Name: , Address: d2:71:05:5a:a6:69, manufacturer data: c7090116230010800300000000000000000000000dc00000, serviceUUID: 0xfe59

I tried using a Whitelist example from another discussion, but it doesn't connect based on the MAC address.

In the NimBLE_Client sketch, if I change the "DEAD" to "fe59" in the line...
pSvc = pClient->getService("fe59");
...it does connect, but the example if so complicated I cannot figure out how to complete the subscription to the notification.
I do not know what the fe59 service is, but it shows up in the advertisement of these probes.
And I want to whitelist based on a single MAC.

I previously could get it to work in the ArduinoBLE library if I roughly did...

BLE.scanForAddress("d2:71:05:5a:a6:69");
peripheral.connect();
peripheral.discoverAttributes();
BLEService service = peripheral.service("00000100-caab-3792-3d44-97ae51c1407a");
BLECharacteristic characteristic = service.characteristic("00000101-caab-3792-3d44-97ae51c1407a");
characteristic.subscribe();

...but it wasn't great, and I really want to use NimBLE on the ESP32.
Is there an easy conversion of this to NimBLE?
ArduinoBLE had to do the Discover Attributes even though they are already known, but I can't seem to find a NimBLE equivalent.

I also need to run this in the main loop so if the connection gets dropped it will just keep retrying.

Thank you in advance for any guidance.

[flynace]

Not sure why my first search didn't uncover it, but I found NimBLEClient::discoverAttributes()
Now I just need to next figure out how to use it...

[h2zero]

Take a look at some of the simpler examples. If you know the service and characteristic UUID you can just get those instead of doing a full discovery.

[flynace]

Thank you for the advice @h2zero
If I run the NimBLE_Scan_Continuous example it sees the probe and prints every time.
But when I try to add the Whitelist feature the callback never prints.
I believe if I can get the Whitelist to work I will be able to figure it out.
Can you advise why the following code is not working?

#include "NimBLEDevice.h"

NimBLEScan* pBLEScan;
NimBLEAddress a("d2:71:05:5a:a6:69");

class MyAdvertisedDeviceCallbacks : public NimBLEAdvertisedDeviceCallbacks {
  void onResult(NimBLEAdvertisedDevice* advertisedDevice) {
    Serial.println(advertisedDevice->getAddress().toString().c_str());
  }
};

void setup() {
  while (!Serial && millis() < 5000);
  Serial.begin(9600);
  Serial.println("Starting...");

  NimBLEDevice::setScanFilterMode(CONFIG_BTDM_SCAN_DUPL_TYPE_DEVICE);
  NimBLEDevice::setScanDuplicateCacheSize(200);

  NimBLEDevice::init("");
  NimBLEDevice::whiteListAdd(a);

  pBLEScan = NimBLEDevice::getScan();  //create new scan
  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks(), true);
  pBLEScan->setFilterPolicy(BLE_HCI_SCAN_FILT_USE_WL);
  pBLEScan->setActiveScan(true);  // Set active scanning, this will get more data from the advertiser.
  pBLEScan->setInterval(97);      // How often the scan occurs / switches channels; in milliseconds,
  pBLEScan->setWindow(37);        // How long to scan during the interval; in milliseconds.
  pBLEScan->setMaxResults(0);     // do not store the scan results, use callback only.
}

void loop() {
  // If an error occurs that stops the scan, it will be restarted here.
  if (pBLEScan->isScanning() == false) {
    // Start scan with: duration = 0 seconds(forever), no scan end callback, not a continuation of a previous scan.
    pBLEScan->start(0, nullptr, false);
  }

  delay(2000);
}

Thank you!

[h2zero]

You need to set the address type to the same as the device advertises with. try: NimBLEAddress a("d2:71:05:5a:a6:69", 1); As it is likely a random static address.