mirror of
https://github.com/miguel5612/MQSensorsLib.git
synced 2025-03-14 21:07:36 +03:00
137 lines
5.2 KiB
C++
137 lines
5.2 KiB
C++
/*
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* This sketch fixes the MQ2 measuring issue when using Wifi.h
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* Wifi.h deactivates pin 25 analogical input on esp32.ino default sketch.
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* This is because Wifi.h works only with ADC1 for analogical measurement
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* Please check the esp32-wroom-32d.jpg image on ESP32 folder
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*
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* ADC1 GPIO
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* ADC1_CH0 (GPIO 36) // only tested on this and it works as expected :)
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* ADC1_CH1 (GPIO 37)
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* ADC1_CH2 (GPIO 38)
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* ADC1_CH3 (GPIO 39)
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* ADC1_CH4 (GPIO 32)
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* ADC1_CH5 (GPIO 33)
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* ADC1_CH6 (GPIO 34)
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* ADC1_CH7 (GPIO 35)
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*
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* ADC2 GPIO
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* ADC2_CH0 (GPIO 4)
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* ADC2_CH1 (GPIO 0)
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* ADC2_CH2 (GPIO 2)
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* ADC2_CH3 (GPIO 15)
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* ADC2_CH4 (GPIO 13)
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* ADC2_CH5 (GPIO 12)
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* ADC2_CH6 (GPIO 14)
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* ADC2_CH7 (GPIO 27)
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* ADC2_CH8 (GPIO 25)
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* ADC2_CH9 (GPIO 26)
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*
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*/
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#include <WiFi.h>
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//Include the library
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#include <MQUnifiedsensor.h>
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/************************Hardware Related Macros************************************/
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#define Board ("ESP-32") // Wemos ESP-32 or other board, whatever have ESP32 core.
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//https://www.amazon.com/HiLetgo-ESP-WROOM-32-Development-Microcontroller-Integrated/dp/B0718T232Z (Although Amazon shows ESP-WROOM-32 ESP32 ESP-32S, the board is the ESP-WROOM-32D)
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#define Pin (36) //check the esp32-wroom-32d.jpg image on ESP32 folder
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/***********************Software Related Macros************************************/
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#define Type ("MQ-2") //MQ2 or other MQ Sensor, if change this verify your a and b values.
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#define Voltage_Resolution (3.3) // 3V3 <- IMPORTANT. Source: https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/
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#define ADC_Bit_Resolution (12) // ESP-32 bit resolution. Source: https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/
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#define RatioMQ2CleanAir (9.83) //RS / R0 = 9.83 ppm
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/*****************************Globals***********************************************/
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MQUnifiedsensor MQ2(Board, Voltage_Resolution, ADC_Bit_Resolution, Pin, Type);
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/*****************************Globals***********************************************/
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const char* ssid = "your-ssid";
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const char* password = "your-password";
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void setup()
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{
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//Init the serial port communication - to debug the library
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Serial.begin(115200); //Init serial port
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delay(10);
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//Set math model to calculate the PPM concentration and the value of constants
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MQ2.setRegressionMethod(1); //_PPM = a*ratio^b
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MQ2.setA(987.99); MQ2.setB(-2.162); // Configure the equation to to calculate H2 concentration
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/*
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Exponential regression:
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Gas | a | b
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H2 | 987.99 | -2.162
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LPG | 574.25 | -2.222
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CO | 36974 | -3.109
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Alcohol| 3616.1 | -2.675
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Propane| 658.71 | -2.168
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*/
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/***************************** MQ Init ********************************************/
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//Remarks: Configure the pin of arduino as input.
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/************************************************************************************/
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MQ2.init();
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/*
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//If the RL value is different from 10K please assign your RL value with the following method:
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MQ2.setRL(10);
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*/
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/***************************** MQ CAlibration ********************************************/
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// Explanation:
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// In this routine the sensor will measure the resistance of the sensor supposedly before being pre-heated
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// and on clean air (Calibration conditions), setting up R0 value.
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// We recomend executing this routine only on setup in laboratory conditions.
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// This routine does not need to be executed on each restart, you can load your R0 value from eeprom.
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// Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
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Serial.print("Calibrating please wait.");
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float calcR0 = 0;
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for(int i = 1; i<=10; i ++)
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{
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MQ2.update(); // Update data, the arduino will read the voltage from the analog pin
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calcR0 += MQ2.calibrate(RatioMQ2CleanAir);
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Serial.print(".");
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}
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MQ2.setR0(calcR0/10);
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Serial.println(" done!.");
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if(isinf(calcR0)) {Serial.println("Warning: Conection issue, R0 is infinite (Open circuit detected) please check your wiring and supply"); while(1);}
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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);}
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/***************************** MQ CAlibration ********************************************/
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//MQ2.serialDebug(true); uncomment if you want to print the table on the serial port
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// We start by connecting to a WiFi network
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Serial.println();
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Serial.println();
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Serial.print("Connecting to ");
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Serial.println(ssid);
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WiFi.begin(ssid, password);
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while (WiFi.status() != WL_CONNECTED) {
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delay(500);
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Serial.print(".");
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}
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Serial.println("");
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Serial.println("WiFi connected");
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Serial.println("IP address: ");
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Serial.println(WiFi.localIP());
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}
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void loop()
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{
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MQ2.update(); // Update data, the arduino will read the voltage from the analog pin
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//MQ2.serialDebug(); // Will print the table on the serial port
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Serial.print(MQ2.readSensor()); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
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Serial.println(" PPM");
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delay(500); //Sampling frequency
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}
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