heartRate.h

/*
 Optical Heart Rate Detection (PBA Algorithm)
 By: Phirat Passi
 
 Given a series of IR samples from the MAX30105 we discern when a heart beat is occurring
 Let's have a brief chat about what this code does. We're going to try to detect
 heart-rate optically. This is tricky and prone to give false readings. We really don't
 want to get anyone hurt so use this code only as an example of how to process optical
 data. Build fun stuff with our MAX30105 breakout board but don't use it for actual
 medical diagnosis.
 Excellent background on optical heart rate detection:
 http://www.ti.com/lit/an/slaa655/slaa655.pdf
 Good reading:
 http://www.techforfuture.nl/fjc_documents/mitrabaratchi-measuringheartratewithopticalsensor.pdf
 https://fruct.org/publications/fruct13/files/Lau.pdf
 This is an implementation of Maxim's PBA (Penpheral Beat Amplitude) algorithm. It's been 
 converted to work within the Arduino framework.
*/

/* Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
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#if (ARDUINO >= 100)
 #include "Arduino.h"
#else
 #include "WProgram.h"
#endif

bool checkForBeat(int32_t sample);
int16_t averageDCEstimator(int32_t *p, uint16_t x);
int16_t lowPassFIRFilter(int16_t din);
int32_t mul16(int16_t x, int16_t y);