ESP32 Arduino Smartwatch Detector with Buzzer

Abhishek Ghosh

By Abhishek Ghosh May 3, 2020 6:59 pm Updated on May 10, 2020

ESP32 Arduino Smartwatch Detector with Buzzer

The series of article Samsung Smartwatch as Proximity Switch taught our readers to learn all required the basic to make ESP32 to respond to a specific smartwatch’s BLE. The same basic was used for the IoT project Detect Smartwatch With ESP32 on IBM Watson IoT Widget. But, still today in everyday life we depend on sound clues more than the visual clues. A door bell or a smoke detector are some examples where a basic buzzer makes usable electronic stuff. We can make ESP32 to make beeping sounds in the presence of a particular smartwatch. The actual challenge of this idea was the limitation of ESP32’s Arduino library. Unlike a “real Arduino”, ESP32’s default library does not support buzzer tones. So, we need to install the library named “EasyBuzzer” :

https://github.com/evert-arias/EasyBuzzer

1	https://github.com/evert-arias/EasyBuzzer

You can install the above library from Arduino IDE by searching with the keyword “EasyBuzzer”. I prefer using pin 13 for the buzzer. So, I modified the value of DEFAULT_PIN in Config.h file from Pin 4 to Pin 13 to get the GND Pin just beside. The file was at :

C:\Users\abhishekghosh\Documents\Arduino\libraries\EasyBuzzer\src

1	C:\Users\abhishekghosh\Documents\Arduino\libraries\EasyBuzzer\src

on my Windows 10 laptop.

ESP32 Arduino Smartwatch Detector with Buzzer

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You can add the buzzer’s positive pin to the Pin 13 (if you modify the pin number, else it will be Pin 4) and negative pin to GND pin of ESP32. Then test the basic examples. This sketch :

#include "EasyBuzzer.h"

unsigned int frequency = 1000;  
unsigned int onDuration = 50;
unsigned int offDuration = 100;
unsigned int beeps = 2;
unsigned int pauseDuration = 500;
unsigned int cycles = 10;

void setup() {
    EasyBuzzer.beep(frequency, onDuration, offDuration, beeps, pauseDuration, cycles);
  }

void loop() {
	EasyBuzzer.update();
}

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#include "EasyBuzzer.h"

unsigned int frequency = 1000;

unsigned int onDuration = 50;

unsigned int offDuration = 100;

unsigned int beeps = 2;

unsigned int pauseDuration = 500;

unsigned int cycles = 10;

void setup() {

EasyBuzzer.beep(frequency, onDuration, offDuration, beeps, pauseDuration, cycles);

}

void loop() {

EasyBuzzer.update();

}

Makes a “beep beep” sound. This is the video I have uploaded on YouTube.

Modifying our old code shared in the part of the previous guide, we can re-write the code to make the ESP32’s buzzer to beep in presence of our smartwatch :

#include "BLEDevice.h"
#include "EasyBuzzer.h"

unsigned int frequency = 1000;  
unsigned int onDuration = 50;
unsigned int offDuration = 100;
unsigned int beeps = 2;
unsigned int pauseDuration = 500;
unsigned int cycles = 10;

int LED = 2; // on-board LED at pin 2
int BUTTON = 0;
static BLEAddress *pServerAddress;
BLEScan* pBLEScan;
BLEClient*  pClient;
bool deviceFound = false;
bool LEDoff = false;
bool BotonOff = false;
String knownAddresses[] = { "e0:a1:07:b7:0b:95"}; // change the MAC
unsigned long entry;

static void notifyCallback(
  BLERemoteCharacteristic* pBLERemoteCharacteristic,
  uint8_t* pData,
  size_t length,
  bool isNotify) {
  Serial.print("Notify callback for characteristic ");
  Serial.print(pBLERemoteCharacteristic->getUUID().toString().c_str());
  Serial.print(" of data length ");
  Serial.println(length);
}

class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {
    void onResult(BLEAdvertisedDevice Device){
      // show the MAC of other BLE devices
      //Serial.print("BLE Advertised Device found: ");
      //Serial.println(Device.toString().c_str());
      pServerAddress = new BLEAddress(Device.getAddress()); 
      bool known = false;
      bool Master = false;
      for (int i = 0; i < (sizeof(knownAddresses) / sizeof(knownAddresses[0])); i++) {
        if (strcmp(pServerAddress->toString().c_str(), knownAddresses[i].c_str()) == 0) 
          known = true;
      }
      if (known) {
        Serial.print("Our device found!");
        Serial.print("Device distance:");
        Serial.println(Device.getRSSI());
        // adjust the value. -85 is medium distance
        // -60 is closer than -85
        if (Device.getRSSI() > -85) {
          deviceFound = true;
        }
        else {
          deviceFound = false;
        }
        Device.getScan()->stop();
        delay(100);
      }
    }
};
void setup() {
  Serial.begin(115200);
  pinMode(LED,OUTPUT);
  digitalWrite(LED,LOW);
  BLEDevice::init("");
  pClient  = BLEDevice::createClient();
  pBLEScan = BLEDevice::getScan();
  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());
  pBLEScan->setActiveScan(true);
  Serial.println("Done");
}
void Bluetooth() {
  Serial.println();
  Serial.println("BLE Scan restarted.....");
  deviceFound = false;
  BLEScanResults scanResults = pBLEScan->start(5);
  if (deviceFound) {
    Serial.println("LED is ON now");
    LEDoff = true;
    digitalWrite(LED,HIGH);
    EasyBuzzer.beep(frequency, onDuration, offDuration, beeps, pauseDuration, cycles);
    BUTTON = 0;
    delay(1000);
  }
  else{
    EasyBuzzer.stopBeep();
    digitalWrite(LED,LOW);
    delay(1000);
  }
}
void loop() { 
  Bluetooth();
  EasyBuzzer.update();
}

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#include "BLEDevice.h"

#include "EasyBuzzer.h"

unsigned int frequency = 1000;

unsigned int onDuration = 50;

unsigned int offDuration = 100;

unsigned int beeps = 2;

unsigned int pauseDuration = 500;

unsigned int cycles = 10;

int LED = 2; // on-board LED at pin 2

int BUTTON = 0;

static BLEAddress *pServerAddress;

BLEScan* pBLEScan;

BLEClient* pClient;

bool deviceFound = false;

bool LEDoff = false;

bool BotonOff = false;

String knownAddresses[] = { "e0:a1:07:b7:0b:95"}; // change the MAC

unsigned long entry;

static void notifyCallback(

BLERemoteCharacteristic* pBLERemoteCharacteristic,

uint8_t* pData,

size_t length,

bool isNotify) {

Serial.print("Notify callback for characteristic ");

Serial.print(pBLERemoteCharacteristic->getUUID().toString().c_str());

Serial.print(" of data length ");

Serial.println(length);

}

class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {

void onResult(BLEAdvertisedDevice Device){

// show the MAC of other BLE devices

//Serial.print("BLE Advertised Device found: ");

//Serial.println(Device.toString().c_str());

pServerAddress = new BLEAddress(Device.getAddress());

bool known = false;

bool Master = false;

for (int i = 0; i < (sizeof(knownAddresses) / sizeof(knownAddresses[0])); i++) {

if (strcmp(pServerAddress->toString().c_str(), knownAddresses[i].c_str()) == 0)

known = true;

}

if (known) {

Serial.print("Our device found!");

Serial.print("Device distance:");

Serial.println(Device.getRSSI());

// adjust the value. -85 is medium distance

// -60 is closer than -85

if (Device.getRSSI() > -85) {

deviceFound = true;

}

else {

deviceFound = false;

}

Device.getScan()->stop();

delay(100);

}

};

void setup() {

Serial.begin(115200);

pinMode(LED,OUTPUT);

digitalWrite(LED,LOW);

BLEDevice::init("");

pClient = BLEDevice::createClient();

pBLEScan = BLEDevice::getScan();

pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());

pBLEScan->setActiveScan(true);

Serial.println("Done");

}

void Bluetooth() {

Serial.println();

Serial.println("BLE Scan restarted.....");

deviceFound = false;

BLEScanResults scanResults = pBLEScan->start(5);

if (deviceFound) {

Serial.println("LED is ON now");

LEDoff = true;

digitalWrite(LED,HIGH);

EasyBuzzer.beep(frequency, onDuration, offDuration, beeps, pauseDuration, cycles);

BUTTON = 0;

delay(1000);

}

else{

EasyBuzzer.stopBeep();

digitalWrite(LED,LOW);

delay(1000);

}

void loop() {

Bluetooth();

EasyBuzzer.update();

}

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ESP32 Arduino Smartwatch Detector with Buzzer

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