Added unit tests! to validate library calculations

2025-07-27 22:51:03 +03:00 · 2022-03-21 14:32:37 -05:00
parent 6a035cc5d0
commit e3f5e2ec0c
5 changed files with 301 additions and 8 deletions
--- a/examples/MQ-303A/MQ-303A.ino
+++ b/examples/MQ-303A/MQ-303A.ino
@ -0,0 +1,92 @@
+/*
+  MQUnifiedsensor Library - reading an MQ303
+
+  Demonstrates the use a MQ303 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-303" //MQ303
+#define ADC_Bit_Resolution 10 // For arduino UNO/MEGA/NANO
+#define RatioMQ303CleanAir 1  //RS / R0 = 1 ppm    
+//#define calibration_button 13 //Pin to calibrate your sensor
+
+//Declare Sensor
+MQUnifiedsensor MQ303(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
+  MQ303.setRegressionMethod(1); //_PPM =  a*ratio^b
+  MQ303.setA(6.2144); MQ303.setB(-2.894); // Configure the equation to to calculate Isobutano concentration
+
+  /*
+    Exponential regression:
+  GAS        | a      | b
+  Iso_butano | 6.2144 | -2.894
+  Hydrogen   | 4.1487 | -2.716
+  Ethanol    | 3.4916 | -2.432
+  */
+
+  /*****************************  MQ Init ********************************************/ 
+  //Remarks: Configure the pin of arduino as input.
+  /************************************************************************************/ 
+  MQ303.init(); 
+  /* 
+    //If the RL value is different from 10K please assign your RL value with the following method:
+    MQ303.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 ++)
+  {
+    MQ303.update(); // Update data, the arduino will read the voltage from the analog pin
+    calcR0 += MQ303.calibrate(RatioMQ303CleanAir);
+    Serial.print(".");
+  }
+  MQ303.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 ********************************************/ 
+  MQ303.serialDebug(true);
+}
+
+void loop() {
+  MQ303.update(); // Update data, the arduino will read the voltage from the analog pin
+  MQ303.readSensor(true); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  MQ303.serialDebug(); // Will print the table on the serial port
+  delay(500); //Sampling frequency
+}