/* Optical Heart Rate Detection (PBA Algorithm) using the MAX30105 Breakout By: Nathan Seidle @ SparkFun Electronics Date: October 2nd, 2016 https://github.com/sparkfun/MAX30105_Breakout This is a demo to show the reading of heart rate or beats per minute (BPM) using a Penpheral Beat Amplitude (PBA) algorithm. It is best to attach the sensor to your finger using a rubber band or other tightening device. Humans are generally bad at applying constant pressure to a thing. When you press your finger against the sensor it varies enough to cause the blood in your finger to flow differently which causes the sensor readings to go wonky. Hardware Connections (Breakoutboard to Arduino): -5V = 5V (3.3V is allowed) -GND = GND -SDA = A4 (or SDA) -SCL = A5 (or SCL) -INT = Not connected The MAX30105 Breakout can handle 5V or 3.3V I2C logic. We recommend powering the board with 5V but it will also run at 3.3V.*/#include <Wire.h>#include "MAX30105.h"#include "heartRate.h"
MAX30105 particleSensor;
const byte RATE_SIZE = 4; //Increase this for more averaging. 4 is good.
byte rates[RATE_SIZE]; //Array of heart rates
byte rateSpot = 0;
long lastBeat = 0; //Time at which the last beat occurredfloat beatsPerMinute;
int beatAvg;
void setup()
{
Serial.begin(115200);
Serial.println("Initializing...");
// Initialize sensorif (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
{
Serial.println("MAX30105 was not found. Please check wiring/power. ");
while (1);
}
Serial.println("Place your index finger on the sensor with steady pressure.");
particleSensor.setup(); //Configure sensor with default settings
particleSensor.setPulseAmplitudeRed(0x0A); //Turn Red LED to low to indicate sensor is running
particleSensor.setPulseAmplitudeGreen(0); //Turn off Green LED
}
void loop()
{
long irValue = particleSensor.getIR();
if (checkForBeat(irValue) == true)
{
//We sensed a beat!long delta = millis() - lastBeat;
lastBeat = millis();
beatsPerMinute = 60 / (delta / 1000.0);
if (beatsPerMinute < 255 && beatsPerMinute > 20)
{
rates[rateSpot++] = (byte)beatsPerMinute; //Store this reading in the array
rateSpot %= RATE_SIZE; //Wrap variable//Take average of readings
beatAvg = 0;
for (byte x = 0 ; x < RATE_SIZE ; x++)
beatAvg += rates[x];
beatAvg /= RATE_SIZE;
}
}
Serial.print("IR=");
Serial.print(irValue);
Serial.print(", BPM=");
Serial.print(beatsPerMinute);
Serial.print(", Avg BPM=");
Serial.print(beatAvg);
if (irValue < 50000)
Serial.print(" No finger?");
Serial.println();
}