ESP32 how to read bluetooth rssi

Projects Programming
1

I'm trying to make a bluetooth scanner that could read the rssi value off from a beacon, I'm currently using the beacon_scanner example from the arduino BLE library but I can't figure out how to add the get rssi function.

2

Is this the code you are running?

libraries/BLE/examples/Beacon_Scanner/Beacon_Scanner.ino

It looks like is should be reporting rssi for iBeacon and Eddystone Beacon. For what Beacon are you trying to detect the rssi?

What is the Serial output from the code you are running?

/*
   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
   Changed to a beacon scanner to report iBeacon, EddystoneURL and EddystoneTLM beacons by beegee-tokyo
   Upgraded Eddystone part by Tomas Pilny on Feb 20, 2023
*/

#include <Arduino.h>

#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>
#include <BLEEddystoneURL.h>
#include <BLEEddystoneTLM.h>
#include <BLEBeacon.h>

int scanTime = 5;  //In seconds
BLEScan *pBLEScan;

class MyAdvertisedDeviceCallbacks : public BLEAdvertisedDeviceCallbacks {
  void onResult(BLEAdvertisedDevice advertisedDevice) {
    if (advertisedDevice.haveName()) {
      Serial.print("Device name: ");
      Serial.println(advertisedDevice.getName().c_str());
      Serial.println("");
    }

    if (advertisedDevice.haveServiceUUID()) {
      BLEUUID devUUID = advertisedDevice.getServiceUUID();
      Serial.print("Found ServiceUUID: ");
      Serial.println(devUUID.toString().c_str());
      Serial.println("");
    }

    if (advertisedDevice.haveManufacturerData() == true) {
      String strManufacturerData = advertisedDevice.getManufacturerData();

      // Buffer to store manufacturer data (BLE max is 255 bytes)
      uint8_t cManufacturerData[255];
      size_t dataLength = strManufacturerData.length();

      // Bounds checking to prevent buffer overflow
      if (dataLength <= sizeof(cManufacturerData)) {
        memcpy(cManufacturerData, strManufacturerData.c_str(), dataLength);

        if (dataLength == 25 && cManufacturerData[0] == 0x4C && cManufacturerData[1] == 0x00) {
          Serial.println("Found an iBeacon!");
          BLEBeacon oBeacon = BLEBeacon();
          oBeacon.setData(strManufacturerData);
          Serial.printf("iBeacon Frame\n");
          Serial.printf(
            "ID: %04X Major: %d Minor: %d UUID: %s Power: %d\n", oBeacon.getManufacturerId(), ENDIAN_CHANGE_U16(oBeacon.getMajor()),
            ENDIAN_CHANGE_U16(oBeacon.getMinor()), oBeacon.getProximityUUID().toString().c_str(), oBeacon.getSignalPower()
          );
        } else {
          Serial.println("Found another manufacturers beacon!");
          Serial.printf("strManufacturerData: %d ", dataLength);
          for (int i = 0; i < dataLength; i++) {
            Serial.printf("[%X]", cManufacturerData[i]);
          }
          Serial.printf("\n");
        }
      } else {
        Serial.printf("Manufacturer data too large (%d bytes), skipping\n", dataLength);
      }
    }

    if (advertisedDevice.getFrameType() == BLE_EDDYSTONE_URL_FRAME) {
      Serial.println("Found an EddystoneURL beacon!");
      BLEEddystoneURL EddystoneURL = BLEEddystoneURL(&advertisedDevice);
      Serial.printf("URL bytes: 0x");
      String url = EddystoneURL.getURL();
      for (auto byte : url) {
        Serial.printf("%02X", byte);
      }
      Serial.printf("\n");
      Serial.printf("Decoded URL: %s\n", EddystoneURL.getDecodedURL().c_str());
      Serial.printf("EddystoneURL.getDecodedURL(): %s\n", EddystoneURL.getDecodedURL().c_str());
      Serial.printf("TX power %d (Raw 0x%02X)\n", EddystoneURL.getPower(), EddystoneURL.getPower());
      Serial.println("\n");
    }

    if (advertisedDevice.getFrameType() == BLE_EDDYSTONE_TLM_FRAME) {
      Serial.println("Found an EddystoneTLM beacon!");
      BLEEddystoneTLM EddystoneTLM(&advertisedDevice);
      Serial.printf("Reported battery voltage: %dmV\n", EddystoneTLM.getVolt());
      Serial.printf("Reported temperature: %.2f°C (raw data=0x%04X)\n", EddystoneTLM.getTemp(), EddystoneTLM.getRawTemp());
      Serial.printf("Reported advertise count: %lu\n", EddystoneTLM.getCount());
      Serial.printf("Reported time since last reboot: %lus\n", EddystoneTLM.getTime());
      Serial.println("\n");
      Serial.print(EddystoneTLM.toString().c_str());
      Serial.println("\n");
    }
  }
};

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);
}