port oxullo library Arduino
Diff: MAX30100_SpO2Calculator.cpp
- Revision:
- 0:010b908e2187
--- /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