Heart Rate Monitor Using OLED Display Program Code.

https://youtu.be/eDDUX42x7nA

Program Code:-

#include <Adafruit_SSD1306.h>
	#define OLED_Address 0x3C // 0x3C device address of I2C OLED. Few other OLED has 0x3D
	Adafruit_SSD1306 oled(128, 64); // create our screen object setting resolution to 128x64
	int a=0;
	int lasta=0;
	int lastb=0;
	int LastTime=0;
	int ThisTime;
	bool BPMTiming=false;
	bool BeatComplete=false;
	int BPM=0;
	#define UpperThreshold 560
	#define LowerThreshold 530
	void setup() {
	oled.begin(SSD1306_SWITCHCAPVCC, OLED_Address);
	oled.clearDisplay();
	oled.setTextSize(2);
	}
	void loop()
	{
	if(a>127)
	{
	oled.clearDisplay();
	a=0;
	lasta=a;
	}
	ThisTime=millis();
	int value=analogRead(0);
	oled.setTextColor(WHITE);
	int b=60-(value/16);
	oled.writeLine(lasta,lastb,a,b,WHITE);
	lastb=b;
	lasta=a;
	if(value>UpperThreshold)
	{
	if(BeatComplete)
	{
	BPM=ThisTime-LastTime;
	BPM=int(60/(float(BPM)/1000));
	BPMTiming=false;
	BeatComplete=false;
	tone(8,1000,250);
	}
	if(BPMTiming==false)
	{
	LastTime=millis();
	BPMTiming=true;
	}
	}
	if((value<LowerThreshold)&(BPMTiming))
	BeatComplete=true;
	oled.writeFillRect(0,50,128,16,BLACK);
	oled.setCursor(0,50);
	oled.print("BPM:");
	oled.print(BPM);
	oled.display();
	a++;
	}