Beacon

#include <bluefruit.h>

// https://www.bluetooth.com/specifications/assigned-numbers/company-identifiers
// 0x004C is Apple (for example)
#define MANUFACTURER_ID   0x004c

// AirLocate UUID: E2C56DB5-DFFB-48D2-B060-D0F5A71096E0
uint8_t beaconUuid[16] =
{
  0xE2, 0xC5, 0x6D, 0xB5, 0xDF, 0xFB, 0x48, 0xD2,
  0xB0, 0x60, 0xD0, 0xF5, 0xA7, 0x10, 0x96, 0xE0,
};

int txpowers[14] = {-40, -20, -16, -12, -8, -4, 0, 2, 3, 4, 5, 6, 7, 8};

void setup()
{
  Serial.begin(115200);
  while ( !Serial ) delay(10);   // for nrf52840 with native usb

  Serial.println("Bluefruit52 Beacon Example");
  Serial.println("--------------------------\n");

  Bluefruit.begin();

  Bluefruit.autoConnLed(false);
  Bluefruit.setName("Bluefruit_tristan");

  size_t txlen = sizeof(txpowers)/sizeof(txpowers[0]);
  for(int i = 0; i < (int) txlen; i++){
    BLEBeacon beacon(beaconUuid, 0x0000, 0x0000, txpowers[i]); // UUID, Major, Minor, RSSI @ 1M
    beacon.setManufacturer(MANUFACTURER_ID);                   // Manufacturer ID is required for Manufacturer Specific Data
    Bluefruit.setTxPower(txpowers[i]);                         // Check bluefruit.h for supported values
    startAdv(beacon);
  }

  Serial.println("Broadcasting beacon, open your beacon app to test");

  // Suspend Loop() to save power, since we didn't have any code there
  // suspendLoop();
}

void startAdv(BLEBeacon beacon)
{
  Bluefruit.Advertising.setBeacon(beacon);

  // Attempt to put sequence number in manufacturing data
  //Bluefruit.Advertising.addData(0x88, "Hi", 0x02);
  //Bluefruit.Advertising.addManufacturerData(data, 4);

  // Secondary Scan Response packet (optional)
  // Since there is no room for 'Name' in Advertising packet
  Bluefruit.ScanResponse.addName();


  // Consider making beacon non-scannable to reduce overhead
  Bluefruit.Advertising.setType(BLE_GAP_ADV_TYPE_NONCONNECTABLE_SCANNABLE_UNDIRECTED);
  Bluefruit.Advertising.restartOnDisconnect(true);
  Bluefruit.Advertising.setInterval(35, 35);    // in unit of 0.625 ms
  Bluefruit.Advertising.setFastTimeout(1);      // number of seconds in fast mode
  Bluefruit.Advertising.start(1);                 // 0 = Don't stop advertising after n seconds
  delay(1000);
  Bluefruit.Advertising.stop();
}

void loop()
{
  // loop is already suspended, CPU will not run loop() at all
}