Revision 0:010b908e2187, committed 2016-11-25

Comitter:

AVELARDEV

Date:

Fri Nov 25 00:52:54 2016 +0000

Commit message:

max30100 example

Changed in this revision

diff -r 000000000000 -r 010b908e2187 MAX30100.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100.cpp	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,199 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "MAX30100.h"
+
+I2C Wire(I2C_SDA , I2C_SCL );
+
+MAX30100::MAX30100()
+{
+
+}
+
+bool MAX30100::begin()
+{
+//    Wire.begin();
+//    Wire.setClock(I2C_BUS_SPEED);
+
+    Wire.frequency(I2C_BUS_SPEED);
+
+    if(!setMode(DEFAULT_MODE))
+        return false;
+    if(!setLedsPulseWidth(DEFAULT_PULSE_WIDTH))
+        return false;
+    if(!setSamplingRate(DEFAULT_SAMPLING_RATE))
+        return false;
+    if(!setLedsCurrent(DEFAULT_IR_LED_CURRENT, DEFAULT_RED_LED_CURRENT))
+        return false;
+    if(!setHighresModeEnabled(true))
+        return false;
+    
+    return true;
+}
+
+bool MAX30100::setMode(Mode mode)
+{
+    if(!writeRegister(MAX30100_REG_MODE_CONFIGURATION, mode))
+        return false;
+    else
+        return true;
+}
+
+bool MAX30100::setLedsPulseWidth(LEDPulseWidth ledPulseWidth)
+{
+    uint8_t previous;
+    if(readRegister(MAX30100_REG_SPO2_CONFIGURATION, &previous))
+        if(!writeRegister(MAX30100_REG_SPO2_CONFIGURATION, (previous & 0xfc) | ledPulseWidth))
+            return false;
+        else
+            return true; 
+    else
+        return false;       
+}
+
+bool MAX30100::setSamplingRate(SamplingRate samplingRate)
+{
+    uint8_t previous;
+    if(readRegister(MAX30100_REG_SPO2_CONFIGURATION, &previous))
+        if(!writeRegister(MAX30100_REG_SPO2_CONFIGURATION, (previous & 0xe3) | (samplingRate << 2)))
+            return false;
+        else
+            return true; 
+    else
+        return false;  
+}
+
+bool MAX30100::setLedsCurrent(LEDCurrent irLedCurrent, LEDCurrent redLedCurrent)
+{
+    if(!writeRegister(MAX30100_REG_LED_CONFIGURATION, redLedCurrent << 4 | irLedCurrent))
+        return false;
+    else
+        return true;     
+}
+
+bool MAX30100::setHighresModeEnabled(bool enabled)
+{
+    uint8_t previous;
+    if(readRegister(MAX30100_REG_SPO2_CONFIGURATION, &previous))
+        if (enabled) {
+            if(!writeRegister(MAX30100_REG_SPO2_CONFIGURATION, previous | MAX30100_SPC_SPO2_HI_RES_EN))
+                return false;
+            else
+                return true; 
+        } else {
+            if(!writeRegister(MAX30100_REG_SPO2_CONFIGURATION, previous & ~MAX30100_SPC_SPO2_HI_RES_EN))
+                return false;
+            else
+                return true;         
+        }
+    else
+        return false;
+}
+
+
+bool MAX30100::update()
+{
+    if(!readFifoData())
+        return false;
+    else
+        return true;
+}
+
+
+/*
+uint8_t MAX30100::readRegister(uint8_t address)
+{
+    Wire.beginTransmission(MAX30100_I2C_ADDRESS);
+    Wire.write(address);
+    Wire.endTransmission(false);
+    Wire.requestFrom(MAX30100_I2C_ADDRESS, 1);
+
+    return Wire.read();
+}
+*/
+
+bool MAX30100::readRegister(uint8_t uch_addr, uint8_t *puch_data)
+/**
+* \brief        Read a MAX30102 register
+* \par          Details
+*               This function reads a MAX30102 register
+*
+* \param[in]    uch_addr    - register address
+* \param[out]   puch_data    - pointer that stores the register data
+*
+* \retval       true on success
+*/
+{
+  char ch_i2c_data;
+  ch_i2c_data=uch_addr;
+  if(Wire.write(I2C_WRITE_ADDR, &ch_i2c_data, 1, true)!=0)
+    return false;
+  if(Wire.read(I2C_READ_ADDR, &ch_i2c_data, 1, false)==0)
+  {
+    *puch_data=(uint8_t) ch_i2c_data;
+    return true;
+  }
+  else
+    return false;   
+}
+
+/*
+void MAX30100::writeRegister(uint8_t address, uint8_t data)
+{
+    Wire.beginTransmission(MAX30100_I2C_ADDRESS);
+    Wire.write(address);
+    Wire.write(data);
+    Wire.endTransmission();
+}
+*/
+
+bool MAX30100::writeRegister(uint8_t uch_addr, uint8_t uch_data)
+/**
+* \brief        Write a value to a MAX30102 register
+* \par          Details
+*               This function writes a value to a MAX30102 register
+*
+* \param[in]    uch_addr    - register address
+* \param[in]    uch_data    - register data
+*
+* \retval       true on success
+*/
+{
+  char ach_i2c_data[2];
+  ach_i2c_data[0]=uch_addr;
+  ach_i2c_data[1]=uch_data;
+  
+  if(Wire.write(I2C_WRITE_ADDR, ach_i2c_data, 2, false)==0)
+    return true;
+  else
+    return false;    
+}
+
+bool MAX30100::readFifoData()
+{
+    char ach_i2c_data[4];
+
+    ach_i2c_data[0]=MAX30100_REG_FIFO_DATA;
+    if(Wire.write(I2C_WRITE_ADDR, ach_i2c_data, 1, true)!=0)
+        return false;
+    if(Wire.read(I2C_READ_ADDR, ach_i2c_data, 4, false)!=0)
+        return false;
+
+    // Warning: the values are always left-aligned
+    rawIRValue = (ach_i2c_data[0] << 8) | ach_i2c_data[1];
+    rawRedValue = (ach_i2c_data[2] << 8) | ach_i2c_data[3];
+    
+    return true;
+}

diff -r 000000000000 -r 010b908e2187 MAX30100.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100.h	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,58 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef MAX30100_H
+#define MAX30100_H
+
+#include <stdint.h>
+#include "mbed.h"
+#include "MAX30100_Registers.h"
+
+#define DEFAULT_MODE                MAX30100_MODE_HRONLY
+#define DEFAULT_SAMPLING_RATE       MAX30100_SAMPRATE_100HZ
+#define DEFAULT_PULSE_WIDTH         MAX30100_SPC_PW_1600US_16BITS
+#define DEFAULT_RED_LED_CURRENT     MAX30100_LED_CURR_50MA
+#define DEFAULT_IR_LED_CURRENT      MAX30100_LED_CURR_50MA
+
+#define I2C_BUS_SPEED               400000UL
+
+class MAX30100 {
+public:
+    MAX30100();
+    bool begin();
+    bool setMode(Mode mode);
+    bool setLedsPulseWidth(LEDPulseWidth ledPulseWidth);
+    bool setSamplingRate(SamplingRate samplingRate);
+    bool setLedsCurrent(LEDCurrent irLedCurrent, LEDCurrent redLedCurrent);
+    bool setHighresModeEnabled(bool enabled);
+    bool update();
+
+    uint16_t rawIRValue;
+    uint16_t rawRedValue;
+
+private:
+    /*
+    uint8_t readRegister(uint8_t address);
+    void writeRegister(uint8_t address, uint8_t data);
+    void burstRead(uint8_t baseAddress, uint8_t *buffer, uint8_t length);
+    void readFifoData();
+    */
+    
+    bool writeRegister(uint8_t uch_addr, uint8_t uch_data);
+    bool readRegister(uint8_t uch_addr, uint8_t *puch_data);
+    bool readFifoData();
+};
+
+#endif
\ No newline at end of file

diff -r 000000000000 -r 010b908e2187 MAX30100_BeatDetector.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_BeatDetector.cpp	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,124 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "MAX30100_BeatDetector.h"
+
+BeatDetector::BeatDetector() :
+    state(BEATDETECTOR_STATE_INIT),
+    threshold(BEATDETECTOR_MIN_THRESHOLD),
+    beatPeriod(0),
+    lastMaxValue(0),
+    tsLastBeat(0)
+{
+    t.start();
+}
+
+bool BeatDetector::addSample(float sample)
+{
+    return checkForBeat(sample);
+}
+
+float BeatDetector::getRate()
+{
+    if (beatPeriod != 0) {
+        return 1 / beatPeriod * 1000 * 60;
+    } else {
+        return 0;
+    }
+}
+
+float BeatDetector::getCurrentThreshold()
+{
+    return threshold;
+}
+
+bool BeatDetector::checkForBeat(float sample)
+{
+    bool beatDetected = false;
+
+    switch (state) {
+        case BEATDETECTOR_STATE_INIT:
+            if (t.read_ms() > BEATDETECTOR_INIT_HOLDOFF) {
+                state = BEATDETECTOR_STATE_WAITING;
+            }
+            break;
+
+        case BEATDETECTOR_STATE_WAITING:
+            if (sample > threshold) {
+                threshold = std::min((uint32_t)sample, (uint32_t)BEATDETECTOR_MAX_THRESHOLD);
+                state = BEATDETECTOR_STATE_FOLLOWING_SLOPE;
+            }
+
+            // Tracking lost, resetting
+            if (t.read_ms() > BEATDETECTOR_INVALID_READOUT_DELAY) {
+                beatPeriod = 0;
+                lastMaxValue = 0;
+            }
+
+            decreaseThreshold();
+            break;
+
+        case BEATDETECTOR_STATE_FOLLOWING_SLOPE:
+            if (sample < threshold) {
+                state = BEATDETECTOR_STATE_MAYBE_DETECTED;
+            } else {
+                threshold = std::min((uint32_t)sample, (uint32_t)BEATDETECTOR_MAX_THRESHOLD);
+            }
+            break;
+
+        case BEATDETECTOR_STATE_MAYBE_DETECTED:
+            if (sample + BEATDETECTOR_STEP_RESILIENCY < threshold) {
+                // Found a beat
+                beatDetected = true;
+                lastMaxValue = sample;
+                state = BEATDETECTOR_STATE_MASKING;
+                float delta = t.read_ms();
+                if (delta) {
+                    beatPeriod = BEATDETECTOR_BPFILTER_ALPHA * delta +
+                            (1 - BEATDETECTOR_BPFILTER_ALPHA) * beatPeriod;
+                }
+
+                t.reset();
+            } else {
+                state = BEATDETECTOR_STATE_FOLLOWING_SLOPE;
+            }
+            break;
+
+        case BEATDETECTOR_STATE_MASKING:
+            if (t.read_ms() > BEATDETECTOR_MASKING_HOLDOFF) {
+                state = BEATDETECTOR_STATE_WAITING;
+            }
+            decreaseThreshold();
+            break;
+    }
+
+    return beatDetected;
+}
+
+void BeatDetector::decreaseThreshold()
+{
+    // When a valid beat rate readout is present, target the
+    if (lastMaxValue > 0 && beatPeriod > 0) {
+        threshold -= lastMaxValue * (1 - BEATDETECTOR_THRESHOLD_FALLOFF_TARGET) /
+                (beatPeriod / BEATDETECTOR_SAMPLES_PERIOD);
+    } else {
+        // Asymptotic decay
+        threshold *= BEATDETECTOR_THRESHOLD_DECAY_FACTOR;
+    }
+
+    if (threshold < BEATDETECTOR_MIN_THRESHOLD) {
+        threshold = BEATDETECTOR_MIN_THRESHOLD;
+    }
+}
\ No newline at end of file

diff -r 000000000000 -r 010b908e2187 MAX30100_BeatDetector.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_BeatDetector.h	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,64 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef MAX30100_BEATDETECTOR_H
+#define MAX30100_BEATDETECTOR_H
+
+#include "mbed.h"
+#include <stdint.h>
+#include <algorithm>
+
+#define BEATDETECTOR_INIT_HOLDOFF                2000    // in ms, how long to wait before counting
+#define BEATDETECTOR_MASKING_HOLDOFF             200     // in ms, non-retriggerable window after beat detection
+#define BEATDETECTOR_BPFILTER_ALPHA              0.6     // EMA factor for the beat period value
+#define BEATDETECTOR_MIN_THRESHOLD               20      // minimum threshold (filtered) value
+#define BEATDETECTOR_MAX_THRESHOLD               800     // maximum threshold (filtered) value
+#define BEATDETECTOR_STEP_RESILIENCY             30      // maximum negative jump that triggers the beat edge
+#define BEATDETECTOR_THRESHOLD_FALLOFF_TARGET    0.3     // thr chasing factor of the max value when beat
+#define BEATDETECTOR_THRESHOLD_DECAY_FACTOR      0.99    // thr chasing factor when no beat
+#define BEATDETECTOR_INVALID_READOUT_DELAY       2000    // in ms, no-beat time to cause a reset
+#define BEATDETECTOR_SAMPLES_PERIOD              10      // in ms, 1/Fs
+
+
+typedef enum BeatDetectorState {
+    BEATDETECTOR_STATE_INIT,
+    BEATDETECTOR_STATE_WAITING,
+    BEATDETECTOR_STATE_FOLLOWING_SLOPE,
+    BEATDETECTOR_STATE_MAYBE_DETECTED,
+    BEATDETECTOR_STATE_MASKING
+} BeatDetectorState;
+
+
+class BeatDetector
+{
+public:
+    BeatDetector();
+    bool addSample(float sample);
+    float getRate();
+    float getCurrentThreshold();
+
+private:
+    bool checkForBeat(float value);
+    void decreaseThreshold();
+
+    BeatDetectorState state;
+    float threshold;
+    float beatPeriod;
+    float lastMaxValue;
+    uint32_t tsLastBeat;
+    Timer t;
+};
+
+#endif
\ No newline at end of file

diff -r 000000000000 -r 010b908e2187 MAX30100_Filters.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_Filters.h	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,71 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef MAX30100_FILTERS_H
+#define MAX30100_FILTERS_H
+
+// http://www.schwietering.com/jayduino/filtuino/
+// Low pass butterworth filter order=1 alpha1=0.1
+// Fs=100Hz, Fc=6Hz
+class  FilterBuLp1
+{
+    public:
+        FilterBuLp1()
+        {
+            v[0]=0.0;
+        }
+    private:
+        float v[2];
+    public:
+        float step(float x) //class II
+        {
+            v[0] = v[1];
+            v[1] = (2.452372752527856026e-1 * x)
+                 + (0.50952544949442879485 * v[0]);
+            return
+                 (v[0] + v[1]);
+        }
+};
+
+// http://sam-koblenski.blogspot.de/2015/11/everyday-dsp-for-programmers-dc-and.html
+class DCRemover
+{
+public:
+    DCRemover() : alpha(0), dcw(0)
+    {
+    }
+    DCRemover(float alpha_) : alpha(alpha_), dcw(0)
+    {
+    }
+
+    float step(float x)
+    {
+        float olddcw = dcw;
+        dcw = (float)x + alpha * dcw;
+
+        return dcw - olddcw;
+    }
+
+    float getDCW()
+    {
+        return dcw;
+    }
+
+private:
+    float alpha;
+    float dcw;
+};
+
+#endif
\ No newline at end of file

diff -r 000000000000 -r 010b908e2187 MAX30100_PulseOximeter.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_PulseOximeter.cpp	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,154 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <mbed.h>
+#include "MAX30100_PulseOximeter.h"
+
+
+PulseOximeter::PulseOximeter() :
+    state(PULSEOXIMETER_STATE_INIT),
+//    tsFirstBeatDetected(0),
+//    tsLastBeatDetected(0),
+//    tsLastSample(0),
+//    tsLastBiasCheck(0),
+//    tsLastCurrentAdjustment(0),
+    redLedPower((uint8_t)RED_LED_CURRENT_START),
+    onBeatDetected(NULL)
+{
+}
+
+bool PulseOximeter::begin(PulseOximeterDebuggingMode debuggingMode_)
+{
+    debuggingMode = debuggingMode_;
+
+    if(!hrm.begin())
+        return false;
+    if(!hrm.setMode(MAX30100_MODE_SPO2_HR))
+        return false;
+    if(!hrm.setLedsCurrent(IR_LED_CURRENT, RED_LED_CURRENT_START))
+        return false;
+
+    irDCRemover = DCRemover(DC_REMOVER_ALPHA);
+    redDCRemover = DCRemover(DC_REMOVER_ALPHA);
+
+    state = PULSEOXIMETER_STATE_IDLE;
+    return true;
+}
+
+
+void PulseOximeter::update()
+{
+    checkSample();
+    checkCurrentBias();   
+}
+
+float PulseOximeter::getHeartRate()
+{
+    return beatDetector.getRate();
+}
+
+uint8_t PulseOximeter::getSpO2()
+{
+    return spO2calculator.getSpO2();
+}
+
+uint8_t PulseOximeter::getRedLedCurrentBias()
+{
+    return redLedPower;
+}
+
+void PulseOximeter::setOnBeatDetectedCallback(void (*cb)())
+{
+    onBeatDetected = cb;
+    t_Sample.start();
+    t_CurrentBias.start();
+}
+
+void PulseOximeter::checkSample()
+{
+    if (t_Sample.read_ms() > 1.0 / SAMPLING_FREQUENCY * 1000.0) {
+        t_Sample.reset();
+        if(hrm.update()){
+            
+            float irACValue = irDCRemover.step(hrm.rawIRValue);
+            float redACValue = redDCRemover.step(hrm.rawRedValue);
+    
+            // The signal fed to the beat detector is mirrored since the cleanest monotonic spike is below zero
+            float filteredPulseValue = lpf.step(-irACValue);
+            bool beatDetected = beatDetector.addSample(filteredPulseValue);
+    
+            if (beatDetector.getRate() > 0) {
+                state = PULSEOXIMETER_STATE_DETECTING;
+                spO2calculator.update(irACValue, redACValue, beatDetected);
+            } else if (state == PULSEOXIMETER_STATE_DETECTING) {
+                state = PULSEOXIMETER_STATE_IDLE;
+                spO2calculator.reset();
+            }
+            /*
+            switch (debuggingMode) {
+                case PULSEOXIMETER_DEBUGGINGMODE_RAW_VALUES:
+                    Serial.print("R:");
+                    Serial.print(hrm.rawIRValue);
+                    Serial.print(",");
+                    Serial.println(hrm.rawRedValue);
+                    break;
+    
+                case PULSEOXIMETER_DEBUGGINGMODE_AC_VALUES:
+                    Serial.print("R:");
+                    Serial.print(irACValue);
+                    Serial.print(",");
+                    Serial.println(redACValue);
+                    break;
+    
+                case PULSEOXIMETER_DEBUGGINGMODE_PULSEDETECT:
+                    Serial.print("R:");
+                    Serial.print(filteredPulseValue);
+                    Serial.print(",");
+                    Serial.println(beatDetector->getCurrentThreshold());
+                    break;
+    
+                default:
+                    break;
+            }
+            */
+            if (beatDetected && onBeatDetected) {
+                onBeatDetected();
+            }
+        }
+    }
+}
+
+void PulseOximeter::checkCurrentBias()
+{
+    // Follower that adjusts the red led current in order to have comparable DC baselines between
+    // red and IR leds. The numbers are really magic: the less possible to avoid oscillations
+    if (t_CurrentBias.read_ms() > CURRENT_ADJUSTMENT_PERIOD_MS) {
+        bool changed = false;
+        if (irDCRemover.getDCW() - redDCRemover.getDCW() > 70000 && redLedPower < MAX30100_LED_CURR_50MA) {
+            ++redLedPower;
+            changed = true;
+        } else if (redDCRemover.getDCW() - irDCRemover.getDCW() > 70000 && redLedPower > 0) {
+            --redLedPower;
+            changed = true;
+        }
+
+        if (changed) {
+            hrm.setLedsCurrent(IR_LED_CURRENT, (LEDCurrent)redLedPower);
+            //tsLastCurrentAdjustment = millis();
+        }
+
+        t_CurrentBias.reset();
+    }
+}

diff -r 000000000000 -r 010b908e2187 MAX30100_PulseOximeter.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_PulseOximeter.h	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,83 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef MAX30100_PULSEOXIMETER_H
+#define MAX30100_PULSEOXIMETER_H
+
+#define SAMPLING_FREQUENCY                  100
+#define CURRENT_ADJUSTMENT_PERIOD_MS        500
+#define IR_LED_CURRENT                      MAX30100_LED_CURR_50MA
+#define RED_LED_CURRENT_START               MAX30100_LED_CURR_27_1MA
+#define DC_REMOVER_ALPHA                    0.95
+
+#include <stdint.h>
+#include <vector>
+
+
+#include "MAX30100.h"
+#include "MAX30100_BeatDetector.h"
+#include "MAX30100_Filters.h"
+#include "MAX30100_SpO2Calculator.h"
+
+typedef enum PulseOximeterState {
+    PULSEOXIMETER_STATE_INIT,
+    PULSEOXIMETER_STATE_IDLE,
+    PULSEOXIMETER_STATE_DETECTING
+} PulseOximeterState;
+
+typedef enum PulseOximeterDebuggingMode {
+    PULSEOXIMETER_DEBUGGINGMODE_NONE,
+    PULSEOXIMETER_DEBUGGINGMODE_RAW_VALUES,
+    PULSEOXIMETER_DEBUGGINGMODE_AC_VALUES,
+    PULSEOXIMETER_DEBUGGINGMODE_PULSEDETECT
+} PulseOximeterDebuggingMode;
+
+
+class PulseOximeter {
+public:
+    PulseOximeter();
+
+    bool begin(PulseOximeterDebuggingMode debuggingMode_=PULSEOXIMETER_DEBUGGINGMODE_NONE);
+    void update();
+    float getHeartRate();
+    uint8_t getSpO2();
+    uint8_t getRedLedCurrentBias();
+    void setOnBeatDetectedCallback(void (*cb)());
+
+private:
+    void checkSample();
+    void checkCurrentBias();
+
+    PulseOximeterState state;
+    PulseOximeterDebuggingMode debuggingMode;
+//    uint32_t tsFirstBeatDetected;
+//    uint32_t tsLastBeatDetected;
+//    uint32_t tsLastSample;
+//    uint32_t tsLastBiasCheck;
+//    uint32_t tsLastCurrentAdjustment;
+    BeatDetector beatDetector;
+    DCRemover irDCRemover;
+    DCRemover redDCRemover;
+    FilterBuLp1 lpf;
+    uint8_t redLedPower;
+    SpO2Calculator spO2calculator;
+    
+    MAX30100 hrm;
+
+    void (*onBeatDetected)();
+    Timer t_Sample;
+    Timer t_CurrentBias;
+};
+#endif
\ No newline at end of file

diff -r 000000000000 -r 010b908e2187 MAX30100_Registers.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_Registers.h	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,108 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef MAX30100_REGISTERS_H
+#define MAX30100_REGISTERS_H
+
+//#define MAX30100_I2C_ADDRESS                    0x57
+#define I2C_WRITE_ADDR 0xAE
+#define I2C_READ_ADDR 0xAF
+
+// Interrupt status register (RO)
+#define MAX30100_REG_INTERRUPT_STATUS           0x00
+#define MAX30100_IS_PWR_RDY                     (1 << 0)
+#define MAX30100_IS_SPO2_RDY                    (1 << 4)
+#define MAX30100_IS_HR_RDY                      (1 << 5)
+#define MAX30100_IS_TEMP_RDY                    (1 << 6)
+#define MAX30100_IS_A_FULL                      (1 << 7)
+
+// Interrupt enable register
+#define MAX30100_REG_INTERRUPT_ENABLE           0x01
+#define MAX30100_IE_ENB_SPO2_RDY                (1 << 4)
+#define MAX30100_IE_ENB_HR_RDY                  (1 << 5)
+#define MAX30100_IE_ENB_TEMP_RDY                (1 << 6)
+#define MAX30100_IE_ENB_A_FULL                  (1 << 7)
+
+// FIFO control and data registers
+#define MAX30100_REG_FIFO_WRITE_POINTER         0x02
+#define MAX30100_REG_FIFO_OVERFLOW_COUNTER      0x03
+#define MAX30100_REG_FIFO_READ_POINTER          0x04
+#define MAX30100_REG_FIFO_DATA                  0x05  // Burst read does not autoincrement addr
+
+// Mode Configuration register
+#define MAX30100_REG_MODE_CONFIGURATION         0x06
+#define MAX30100_MC_TEMP_EN                     (1 << 3)
+#define MAX30100_MC_RESET                       (1 << 6)
+#define MAX30100_MC_SHDN                        (1 << 7)
+typedef enum Mode {
+    MAX30100_MODE_HRONLY    = 0x02,
+    MAX30100_MODE_SPO2_HR   = 0x03
+} Mode;
+
+// SpO2 Configuration register
+// Check tables 8 and 9, p19 of the MAX30100 datasheet to see the permissible
+// combinations of sampling rates and pulse widths
+#define MAX30100_REG_SPO2_CONFIGURATION         0x07
+#define MAX30100_SPC_SPO2_HI_RES_EN             (1 << 6)
+typedef enum SamplingRate {
+    MAX30100_SAMPRATE_50HZ      = 0x00,
+    MAX30100_SAMPRATE_100HZ     = 0x01,
+    MAX30100_SAMPRATE_167HZ     = 0x02,
+    MAX30100_SAMPRATE_200HZ     = 0x03,
+    MAX30100_SAMPRATE_400HZ     = 0x04,
+    MAX30100_SAMPRATE_600HZ     = 0x05,
+    MAX30100_SAMPRATE_800HZ     = 0x06,
+    MAX30100_SAMPRATE_1000HZ    = 0x07
+} SamplingRate;
+
+typedef enum LEDPulseWidth {
+    MAX30100_SPC_PW_200US_13BITS    = 0x00,
+    MAX30100_SPC_PW_400US_14BITS    = 0x01,
+    MAX30100_SPC_PW_800US_15BITS    = 0x02,
+    MAX30100_SPC_PW_1600US_16BITS   = 0x03
+} LEDPulseWidth;
+
+// LED Configuration register
+#define MAX30100_REG_LED_CONFIGURATION          0x09
+typedef enum LEDCurrent {
+    MAX30100_LED_CURR_0MA      = 0x00,
+    MAX30100_LED_CURR_4_4MA    = 0x01,
+    MAX30100_LED_CURR_7_6MA    = 0x02,
+    MAX30100_LED_CURR_11MA     = 0x03,
+    MAX30100_LED_CURR_14_2MA   = 0x04,
+    MAX30100_LED_CURR_17_4MA   = 0x05,
+    MAX30100_LED_CURR_20_8MA   = 0x06,
+    MAX30100_LED_CURR_24MA     = 0x07,
+    MAX30100_LED_CURR_27_1MA   = 0x08,
+    MAX30100_LED_CURR_30_6MA   = 0x09,
+    MAX30100_LED_CURR_33_8MA   = 0x0a,
+    MAX30100_LED_CURR_37MA     = 0x0b,
+    MAX30100_LED_CURR_40_2MA   = 0x0c,
+    MAX30100_LED_CURR_43_6MA   = 0x0d,
+    MAX30100_LED_CURR_46_8MA   = 0x0e,
+    MAX30100_LED_CURR_50MA     = 0x0f
+} LEDCurrent;
+
+// Temperature integer part register
+#define MAX30100_REG_TEMPERATURE_DATA_INT       0x16
+// Temperature fractional part register
+#define MAX30100_REG_TEMPERATURE_DATA_FRAC      0x17
+
+// Revision ID register (RO)
+#define MAX30100_REG_REVISION_ID                0xfe
+// Part ID register
+#define MAX30100_REG_PART_ID                    0xff
+
+#endif
\ No newline at end of file

diff -r 000000000000 -r 010b908e2187 MAX30100_SpO2Calculator.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_SpO2Calculator.cpp	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,71 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <math.h>
+
+#include "MAX30100_SpO2Calculator.h"
+
+// SaO2 Look-up Table
+// http://www.ti.com/lit/an/slaa274b/slaa274b.pdf
+const uint8_t SpO2Calculator::spO2LUT[43] = {100,100,100,100,99,99,99,99,99,99,98,98,98,98,
+                                             98,97,97,97,97,97,97,96,96,96,96,96,96,95,95,
+                                             95,95,95,95,94,94,94,94,94,93,93,93,93,93};
+
+SpO2Calculator::SpO2Calculator() :
+    irACValueSqSum(0),
+    redACValueSqSum(0),
+    beatsDetectedNum(0),
+    samplesRecorded(0),
+    spO2(0)
+{
+}
+
+void SpO2Calculator::update(float irACValue, float redACValue, bool beatDetected)
+{
+    irACValueSqSum += irACValue * irACValue;
+    redACValueSqSum += redACValue * redACValue;
+    ++samplesRecorded;
+
+    if (beatDetected) {
+        ++beatsDetectedNum;
+        if (beatsDetectedNum == CALCULATE_EVERY_N_BEATS) {
+            float acSqRatio = 100.0 * log(redACValueSqSum/samplesRecorded) / log(irACValueSqSum/samplesRecorded);
+            uint8_t index = 0;
+
+            if (acSqRatio > 66) {
+                index = (uint8_t)acSqRatio - 66;
+            } else if (acSqRatio > 50) {
+                index = (uint8_t)acSqRatio - 50;
+            }
+            reset();
+
+            spO2 = spO2LUT[index];
+        }
+    }
+}
+
+void SpO2Calculator::reset()
+{
+    samplesRecorded = 0;
+    redACValueSqSum = 0;
+    irACValueSqSum = 0;
+    beatsDetectedNum = 0;
+    spO2 = 0;
+}
+
+uint8_t SpO2Calculator::getSpO2()
+{
+    return spO2;
+}
\ No newline at end of file

diff -r 000000000000 -r 010b908e2187 MAX30100_SpO2Calculator.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_SpO2Calculator.h	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,41 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef MAX30100_SPO2CALCULATOR_H
+#define MAX30100_SPO2CALCULATOR_H
+
+#include <stdint.h>
+
+#define CALCULATE_EVERY_N_BEATS         3
+
+class SpO2Calculator {
+public:
+    SpO2Calculator();
+
+    void update(float irACValue, float redACValue, bool beatDetected);
+    void reset();
+    uint8_t getSpO2();
+
+private:
+    static const uint8_t spO2LUT[43];
+
+    float irACValueSqSum;
+    float redACValueSqSum;
+    uint8_t beatsDetectedNum;
+    uint32_t samplesRecorded;
+    uint8_t spO2;
+};
+
+#endif
\ No newline at end of file