Once removing the for(;;); it solves the crash issue but bpm is not getting any values. Bpm = 0. Funny enough, the sample code works with the pulse sensor with Arduino Mega; i’m getting bpm values while with the ESP8266, it doesn’t get values.
Upon further researching, the PulseSensorPlayground Library that is used in the code uses interrupt in it’s code which doesn’t work well with esp8266? Currently, still finding other alternative to work around the interrupt problem 
/* Getting_BPM_to_Monitor prints the BPM to the Serial Monitor, using the least lines of code and PulseSensor Library.
* Tutorial Webpage: https://pulsesensor.com/pages/getting-advanced
*
--------Use This Sketch To------------------------------------------
1) Displays user's live and changing BPM, Beats Per Minute, in Arduino's native Serial Monitor.
2) Print: "♥ A HeartBeat Happened !" when a beat is detected, live.
2) Learn about using a PulseSensor Library "Object".
4) Blinks LED on PIN 13 with user's Heartbeat.
--------------------------------------------------------------------*/
#define USE_ARDUINO_INTERRUPTS false // Set-up low-level interrupts for most acurate BPM math.
#include <PulseSensorPlayground.h> // Includes the PulseSensorPlayground Library.
// Variables
const int PulseWire = 0; // PulseSensor PURPLE WIRE connected to ANALOG PIN 0
const int LED13 = 13; // The on-board Arduino LED, close to PIN 13.
int Threshold = 550; // Determine which Signal to "count as a beat" and which to ignore.
// Use the "Gettting Started Project" to fine-tune Threshold Value beyond default setting.
// Otherwise leave the default "550" value.
PulseSensorPlayground pulseSensor; // Creates an instance of the PulseSensorPlayground object called "pulseSensor"
void setup() {
Serial.begin(9600); // For Serial Monitor
// Configure the PulseSensor object, by assigning our variables to it.
pulseSensor.analogInput(PulseWire);
pulseSensor.blinkOnPulse(LED13); //auto-magically blink Arduino's LED with heartbeat.
pulseSensor.setThreshold(Threshold);
// Double-check the "pulseSensor" object was created and "began" seeing a signal.
if (pulseSensor.begin()) {
Serial.println("We created a pulseSensor Object !"); //This prints one time at Arduino power-up, or on Arduino reset.
}
}
void loop() {
if (pulseSensor.sawNewSample()) {
int myBPM = pulseSensor.getBeatsPerMinute(); // Calls function on our pulseSensor object that returns BPM as an "int".
if (pulseSensor.sawStartOfBeat()) { // Constantly test to see if "a beat happened".
Serial.println("♥ A HeartBeat Happened ! "); // If test is "true", print a message "a heartbeat happened".
Serial.print("BPM: "); // Print phrase "BPM: "
Serial.println(myBPM); // Print the value inside of myBPM.
}
}
}
Just tested out and found out that the above code works on the ESP8266 and I am able to get bpm values. This is because it is an alternative code for device that has problem with interrupt, provided in the library. Right now, I have trouble putting in Blynk code. Any help?
#define USE_ARDUINO_INTERRUPTS false // Set-up low-level interrupts for most acurate BPM math.
#include <PulseSensorPlayground.h> // Includes the PulseSensorPlayground Library.
#include <SPI.h>
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
// Pulse Variables
const int PulseWire = 0; // PulseSensor PURPLE WIRE connected to ANALOG PIN 0
const int LED13 = 13; // The on-board Arduino LED, close to PIN 13.
int Threshold = 550; // Determine which Signal to "count as a beat" and which to ignore.
// Use the "Gettting Started Project" to fine-tune Threshold Value beyond default setting.
// Otherwise leave the default "550" value.
PulseSensorPlayground pulseSensor; // Creates an instance of the PulseSensorPlayground object called "pulseSensor"
BlynkTimer timer;
char auth[] = "********"; //Enter the Auth code which was send by Blink
// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "******"; //Enter your WIFI Name
char pass[] = "****"; //Enter your WIFI Password
void setup() {
Serial.begin(9600); // For Serial Monitor
Blynk.begin(auth, ssid, pass);
// Setup a function to be called every second
timer.setInterval(1000L, sensorDataSend);
// Configure the PulseSensor object, by assigning our variables to it.
pulseSensor.analogInput(PulseWire);
pulseSensor.blinkOnPulse(LED13); //auto-magically blink Arduino's LED with heartbeat.
pulseSensor.setThreshold(Threshold);
// Double-check the "pulseSensor" object was created and "began" seeing a signal.
if (pulseSensor.begin()) {
Serial.println("We created a pulseSensor Object !"); //This prints one time at Arduino power-up, or on Arduino reset.
}
}
void sensorDataSend() {
if (pulseSensor.sawNewSample()) {
int myBPM = pulseSensor.getBeatsPerMinute(); // Calls function on our pulseSensor object that returns BPM as an "int".
if (pulseSensor.sawStartOfBeat()) { // Constantly test to see if "a beat happened".
Serial.println("♥ A HeartBeat Happened ! "); // If test is "true", print a message "a heartbeat happened".
Serial.print("BPM: "); // Print phrase "BPM: "
Serial.println(myBPM); // Print the value inside of myBPM.
Blynk.virtualWrite(V1, myBPM);
}
}
}
void loop() {
// put your main code here, to run repeatedly:;
Blynk.run(); // Initiates Blynk
timer.run(); // Initiates SimpleTimer
}
This is the working pulse sensor code with the blynk added but unfortunately, it causes it not to run; serial monitor is not showing anything. Where could have gone wrong?
