mirror of
https://github.com/miguel5612/MQSensorsLib.git
synced 2025-03-15 05:17:30 +03:00
93 lines
4.4 KiB
C++
93 lines
4.4 KiB
C++
// This is an example of implementation using ESP8266
|
|
// Never connect the sensor direct to the ESP8266, sensor high level is 5V
|
|
// ADC of ESP8266 high level is 3.3
|
|
// To connect use a voltage divisor, where 5V will 3v3 on the middle point like
|
|
// this {{URL}}
|
|
|
|
/*
|
|
MQUnifiedsensor Library - reading an MQSensor using ESP8266 board
|
|
|
|
For this example wi will demonstrates the use a MQ3 sensor.
|
|
Library originally added 01 may 2019
|
|
by Miguel A Califa, Yersson Carrillo, Ghiordy Contreras, Mario Rodriguez
|
|
|
|
Added ESP8266 example
|
|
29.03.2020
|
|
Wiring:
|
|
https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/static/img/MQ_ESP8266.PNG
|
|
|
|
This example code is in the public domain.
|
|
|
|
*/
|
|
|
|
//Include the library
|
|
#include <MQUnifiedsensor.h>
|
|
/************************Hardware Related Macros************************************/
|
|
#define Board ("ESP-32") // Wemos ESP-32 or other board, whatever have ESP32 core.
|
|
#define Pin (25) //IO25 for your ESP32 WeMos Board, pinout here: https://i.pinimg.com/originals/66/9a/61/669a618d9435c702f4b67e12c40a11b8.jpg
|
|
/***********************Software Related Macros************************************/
|
|
#define Type ("MQ-3") //MQ3 or other MQ Sensor, if change this verify your a and b values.
|
|
#define Voltage_Resolution (3.3) // 3V3 <- IMPORTANT. Source: https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/
|
|
#define ADC_Bit_Resolution (12) // ESP-32 bit resolution. Source: https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/
|
|
#define RatioMQ3CleanAir (60) // Ratio of your sensor, for this example an MQ-3
|
|
/*****************************Globals***********************************************/
|
|
MQUnifiedsensor MQ3(Board, Voltage_Resolution, ADC_Bit_Resolution, Pin, Type);
|
|
/*****************************Globals***********************************************/
|
|
|
|
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); // Configure the equation to to calculate 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 Init ********************************************/
|
|
//Remarks: Configure the pin of arduino as input.
|
|
/************************************************************************************/
|
|
MQ3.init();
|
|
|
|
/*
|
|
//If the RL value is different from 10K please assign your RL value with the following method:
|
|
MQ3.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 ++)
|
|
{
|
|
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 ********************************************/
|
|
MQ3.serialDebug(true);
|
|
}
|
|
|
|
void loop() {
|
|
MQ3.update(); // Update data, the arduino will read the voltage from the analog pin
|
|
MQ3.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
|
|
MQ3.serialDebug(); // Will print the table on the serial port
|
|
delay(500); //Sampling frequency
|
|
} |