From 1840c75c0a8234979779e6b9e8e00aa9629be3ae Mon Sep 17 00:00:00 2001 From: miguel5612 Date: Sun, 29 Mar 2020 22:03:45 -0500 Subject: [PATCH] Added external A2_D Support --- examples/external_A2D/external_A2D.ino | 95 ++++++++++++++++++++++++++ src/MQUnifiedsensor.cpp | 7 +- src/MQUnifiedsensor.h | 1 + 3 files changed, 102 insertions(+), 1 deletion(-) create mode 100644 examples/external_A2D/external_A2D.ino diff --git a/examples/external_A2D/external_A2D.ino b/examples/external_A2D/external_A2D.ino new file mode 100644 index 0000000..c9ab1d0 --- /dev/null +++ b/examples/external_A2D/external_A2D.ino @@ -0,0 +1,95 @@ +/* + MQUnifiedsensor Library - reading an MQ3 + + Demonstrates the use a MQ3 sensor. + Library originally added 01 may 2019 + by Miguel A Califa, Yersson Carrillo, Ghiordy Contreras, Mario Rodriguez + + Added example + modified 23 May 2019 + by Miguel Califa + + Updated library usage + modified 26 March 2020 + by Miguel Califa + + Wiring: + https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/static/img/MQ_Arduino.PNG + Please take care, arduino A0 pin represent the analog input configured on #define pin + + This example code is in the public domain. + +*/ + +//Include the library +#include + +//Definitions +#define placa "Arduino UNO" +#define Voltage_Resolution 5 +#define pin A0 //Analog input 0 -> This value can have any number, we recomend use A0 +#define type "MQ-3 With A2D External connected" //MQ3 +#define ADC_Bit_Resolution 10 // Resolution of your external A2D +#define RatioMQ3CleanAir 60 //RS / R0 = 60 ppm +//#define calibration_button 13 //Pin to calibrate your sensor + +//Declare Sensor +MQUnifiedsensor MQ3(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type); + +void setup() { + //Init the serial port communication - to debug the library + Serial.begin(9600); //Init serial port + + //Set math model to calculate the PPM concentration and the value of constants + MQ3.setRegressionMethod(1); //_PPM = a*ratio^b + MQ3.setA(4.8387); MQ3.setB(-2.68); // Configurate the ecuation values to get Benzene concentration + /* + Exponential regression: + Gas | a | b + LPG | 44771 | -3.245 + CH4 | 2*10^31| 19.01 + CO | 521853 | -3.821 + Alcohol| 0.3934 | -1.504 + Benzene| 4.8387 | -2.68 + Hexane | 7585.3 | -2.849 + */ + + + /***************************** MQ CAlibration ********************************************/ + // Explanation: + // In this routine the sensor will measure the resistance of the sensor supposing before was pre-heated + // and now is on clean air (Calibration conditions), and it will setup R0 value. + // We recomend execute this routine only on setup or on the laboratory and save on the eeprom of your arduino + // This routine not need to execute to every restart, you can load your R0 if you know the value + // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor + Serial.print("Calibrating please wait."); + float calcR0 = 0; + for(int i = 1; i<=10; i ++) + { + int yourA2DValue = random(0, 1024); // 10-bit emulation + MQ3.setADC(yourA2DValue);// Update data, the arduino will be read the voltage on the analog pin + calcR0 += MQ3.calibrate(RatioMQ3CleanAir); + Serial.print("."); + } + MQ3.setR0(calcR0/10); + Serial.println(" done!."); + + if(isinf(calcR0)) {Serial.println("Warning: Conection issue founded, R0 is infite (Open circuit detected) please check your wiring and supply"); while(1);} + if(calcR0 == 0){Serial.println("Warning: Conection issue founded, R0 is zero (Analog pin with short circuit to ground) please check your wiring and supply"); while(1);} + /***************************** MQ CAlibration ********************************************/ + + /* + //If the RL value is different from 10K please assign your RL value with the following method: + MQ3.setRL(10); + */ + + MQ3.serialDebug(true); +} + +void loop() { + int yourA2DValue = random(0, 1024); // 10-bit emulation + MQ3.setADC(yourA2DValue); // Update data, the arduino will be read the voltage on the analog pin + MQ3.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted before or in the setup + MQ3.serialDebug(); // Will print the table on the serial port + delay(500); //Sampling frequency +} \ No newline at end of file diff --git a/src/MQUnifiedsensor.cpp b/src/MQUnifiedsensor.cpp index 265ec8e..fee8ff6 100644 --- a/src/MQUnifiedsensor.cpp +++ b/src/MQUnifiedsensor.cpp @@ -25,6 +25,11 @@ void MQUnifiedsensor::setR0(float R0) { void MQUnifiedsensor::setRL(float RL) { this->_RL = RL; } +void MQUnifiedsensor::setADC(int value) +{ + this-> _sensor_volt = (value) * _VOLT_RESOLUTION / (pow(2, ADC_RESOLUTION) - 1); + this-> _adc = value; +} void MQUnifiedsensor::setVoltResolution(float voltage_resolution) { _VOLT_RESOLUTION = voltage_resolution; @@ -93,7 +98,7 @@ void MQUnifiedsensor::serialDebug(bool onSetup) Serial.print("|"); Serial.print(_adc); Serial.print("| v = ADC*"); Serial.print(_VOLT_RESOLUTION); Serial.print("/"); Serial.print(pow(2, _ADC_Bit_Resolution)); Serial.print(" | "); Serial.print(_sensor_volt); Serial.print(" | RS = ((" ); Serial.print(_VOLT_RESOLUTION ); Serial.print("*RL)/Voltage) - RL| "); Serial.print(_RS_Calc); Serial.print(" | Ratio = RS/R0| "); Serial.print(_ratio); Serial.print( " | "); - if(_regressionMethod == 1) Serial.println("ratio*a + b"); + if(_regressionMethod == 1) Serial.print("ratio*a + b"); else Serial.print("pow(10, (log10(ratio)-b)/a)"); Serial.print(" | "); Serial.print(_PPM); Serial.println(" |"); } diff --git a/src/MQUnifiedsensor.h b/src/MQUnifiedsensor.h index 0bad32e..fabb20b 100644 --- a/src/MQUnifiedsensor.h +++ b/src/MQUnifiedsensor.h @@ -25,6 +25,7 @@ class MQUnifiedsensor void setRegressionMethod(int regressionMethod); void setVoltResolution(float voltage_resolution = 5); void serialDebug(bool onSetup = false); //Show on serial port information about sensor + void setADC(int value); //For external ADC Usage //user functions float calibrate(float ratioInCleanAir);