56 lines
1.4 KiB
C++
Executable File
56 lines
1.4 KiB
C++
Executable File
/**************************************************************************/
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/*!
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@file MQ135.h
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@author G.Krocker (Mad Frog Labs)
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@license GNU GPLv3
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First version of an Arduino Library for the MQ135 gas sensor
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TODO: Review the correction factor calculation. This currently relies on
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the datasheet but the information there seems to be wrong.
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@section HISTORY
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v1.0 - First release
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*/
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/**************************************************************************/
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#ifndef MQ135_H
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#define MQ135_H
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#if ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include "WProgram.h"
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#endif
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/// The load resistance on the board
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#define RLOAD 10.0
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/// Calibration resistance at atmospheric CO2 level
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#define RZERO 76.63
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/// Parameters for calculating ppm of CO2 from sensor resistance
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#define PARA 116.6020682
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#define PARB 2.769034857
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/// Parameters to model temperature and humidity dependence
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#define CORA 0.00035
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#define CORB 0.02718
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#define CORC 1.39538
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#define CORD 0.0018
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/// Atmospheric CO2 level for calibration purposes
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#define ATMOCO2 397.13
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class MQ135 {
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private:
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uint8_t _pin;
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public:
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MQ135(uint8_t pin);
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float getCorrectionFactor(float t, float h);
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float getResistance();
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float getCorrectedResistance(float t, float h);
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float getPPM();
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float getCorrectedPPM(float t, float h);
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float getRZero();
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float getCorrectedRZero(float t, float h);
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};
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#endif
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