MQSensorsLib/examples/Alcoholimeter/Alcoholimeter.ino
2022-03-20 12:53:36 -05:00

95 lines
3.9 KiB
C++

/*
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 29 March 2020
by Miguel Califa
Wiring:
https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/static/img/MQ_Arduino.PNG
Please make sure arduino A0 pin represents the analog input configured on #define pin
This example code is in the public domain.
*/
//Include the library
#include <MQUnifiedsensor.h>
/************************Hardware Related Macros************************************/
#define Board ("Arduino UNO")
#define Pin (A3) //Analog input 3 of your arduino
/***********************Software Related Macros************************************/
#define Type ("MQ-3") //MQ3
#define Voltage_Resolution (5)
#define ADC_Bit_Resolution (10) // For arduino UNO/MEGA/NANO
/*****************************Globals***********************************************/
double alcoholPPM = (0);
/**************************Object_Sensor********************************************/
MQUnifiedsensor MQ3(Board, 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(0.3934); MQ3.setB(-1.504); //Configure the equation to calculate Alcohol concentration value
/*
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
*/
/*
//If the RL value is different from 10K please assign your RL value with the following method:
MQ3.setRL(10);
*/
/***************************** MQ Init ********************************************/
//Remarks: Configure the pin of arduino as input.
/************************************************************************************/
MQ3.init();
/***************************** MQ CAlibration ********************************************/
// Explanation:
// In this routine the sensor will measure the resistance of the sensor supposedly before being pre-heated
// and on clean air (Calibration conditions), setting up R0 value.
// We recomend executing this routine only on setup in laboratory conditions.
// This routine does not need to be executed on each restart, you can load your R0 value from eeprom.
// Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
Serial.print("Calibrating please wait.");
float calcR0 = 0;
for(int i = 1; i<=10; i ++)
{
MQ3.update(); // Update data, the arduino will read the voltage from the analog pin
calcR0 += MQ3.calibrate(RatioMQ3CleanAir);
Serial.print(".");
}
MQ3.setR0(calcR0/10);
Serial.println(" done!.");
if(isinf(calcR0)) {Serial.println("Warning: Conection issue, R0 is infinite (Open circuit detected) please check your wiring and supply"); while(1);}
if(calcR0 == 0){Serial.println("Warning: Conection issue found, R0 is zero (Analog pin shorts to ground) please check your wiring and supply"); while(1);}
/***************************** MQ CAlibration ********************************************/
}
void loop() {
MQ3.update(); // Update data, the arduino will read the voltage from the analog pin
alcoholPPM = MQ3.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
Serial.print("Alcohol now (PPM): ");
Serial.println(alcoholPPM);
delay(500); //Sampling frequency
}