mirror of
https://github.com/miguel5612/MQSensorsLib.git
synced 2025-03-25 10:10:01 +03:00
115 lines
4.3 KiB
C++
115 lines
4.3 KiB
C++
/*
|
|
MQUnifiedsensor Library - reading an MQ309
|
|
|
|
Demonstrates the use a MQ309 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 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>
|
|
|
|
//Definitions
|
|
#define placa "Arduino UNO"
|
|
#define Voltage_Resolution 5
|
|
#define pin A0 //Analog input 0 of your arduino
|
|
#define type "MQ-309" //MQ309
|
|
#define ADC_Bit_Resolution 10 // For arduino UNO/MEGA/NANO
|
|
#define RatioMQ309CleanAir 11 //RS / R0 = 11 ppm
|
|
#define PWMPin 5 // Pin connected to mosfet
|
|
|
|
//Declare Sensor
|
|
MQUnifiedsensor MQ309(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type);
|
|
unsigned long oldTime = 0;
|
|
|
|
void setup() {
|
|
//Init the serial port communication - to debug the library
|
|
Serial.begin(9600); //Init serial port
|
|
pinMode(PWMPin, OUTPUT);
|
|
|
|
//Set math model to calculate the PPM concentration and the value of constants
|
|
MQ309.setRegressionMethod(1); //_PPM = a*ratio^b
|
|
MQ309.setA(1000000); MQ309.setB(-4.01); // Configure the equation to calculate CO concentration value
|
|
|
|
/*
|
|
Exponential regression:
|
|
GAS | a | b
|
|
H2 | 1532.9 | -1.951
|
|
CH4 | 980.24 | -1.68
|
|
CO | 1000000 | -4.01
|
|
ALCOHOL | 473622 | -3.647
|
|
*/
|
|
|
|
/***************************** MQ Init ********************************************/
|
|
//Remarks: Configure the pin of arduino as input.
|
|
/************************************************************************************/
|
|
MQ309.init();
|
|
/*
|
|
//If the RL value is different from 10K please assign your RL value with the following method:
|
|
MQ309.setRL(10);
|
|
*/
|
|
/***************************** 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 ++)
|
|
{
|
|
MQ309.update(); // Update data, the arduino will read the voltage from the analog pin
|
|
calcR0 += MQ309.calibrate(RatioMQ309CleanAir);
|
|
Serial.print(".");
|
|
}
|
|
MQ309.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 ********************************************/
|
|
MQ309.serialDebug(true);
|
|
}
|
|
|
|
void loop() {
|
|
// 60s cycle
|
|
oldTime = millis();
|
|
while(millis() - oldTime <= (30*1000))
|
|
{
|
|
// VH 0.9 Volts
|
|
analogWrite(5, 2); // 255 is 100%, 2.295 is aprox 0.9% of Duty cycle for 60s
|
|
MQ309.update(); // Update data, the arduino will read the voltage from the analog pin
|
|
MQ309.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
|
|
MQ309.serialDebug(); // Will print the table on the serial port
|
|
delay(500); //Sampling frequency
|
|
}
|
|
|
|
// 90s cycle
|
|
oldTime = millis();
|
|
while(millis() - oldTime <= (120*1000))
|
|
{
|
|
// VL 0.2 Volts
|
|
analogWrite(5, 1); // 255 is 100%, 0.51 is aprox 0.2% of Duty cycle for 120s
|
|
MQ309.update(); // Update data, the arduino will read the voltage from the analog pin
|
|
MQ309.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
|
|
MQ309.serialDebug(); // Will print the table on the serial port
|
|
delay(500); //Sampling frequency
|
|
}
|
|
// Total: 30 + 120s = 2.5 minutes.
|
|
} |