How-To-Calibration.md

Finding Ro (Reverse Osmosis) Value

#include "MQ2_LPG.h" // library declaration
#define MQ2PIN A0 // mq2 pin declaration

MQ2Sensor mq2(MQ2PIN); // create a new object with the name mq2 to hold the MQ2Sensor class

void setup() {
  Serial.begin(9600); // default baudrate for the Arduino board
  mq2.begin(); // initiate mq2 sensor
}

// gas calibration data
#define RL_Value 10 // 10K ohm
#define x1_Value 0
#define x2_Value 0
#define y1_Value 0
#define y2_Value 0
#define x_Value 0
#define y_Value 0
#define Voltage_Value 5.0
#define bitADC_Value 1023.0 // development board adc resolution

void calibration(){
  mq2.RL(RL_Value); // resistance load setting
  mq2.Volt(Voltage_Value); // voltage sensor setting
  mq2.BitADC(bitADC_Value); // development board adc resolution setting
  mq2.mCurve(x1_Value, x2_Value, y1_Value, y2_Value); // mCurve setting
  mq2.bCurve(x_Value, y_Value); // bCurve setting
  mq2.getCalibrationData(); // get data calibration
  mq2.viewCalibrationData(); // print to serial monitor: data calibration
}

void loop() {
  calibration(); // calls calibration method
  delay(3000); // delay for 3 seconds
}

After the Ro data is obtained, the next step is to enter the Ro data into the #define section.

#define Ro_Value 6.31

Finding the Right Coordinate Point

Open the following link: WebPlotDigitizer , then click Launch Now!. Then click Load Image. You can find out more about this below.

Upload the image according to the link provided: Click here.

Then choose a plot type: 2D (X-Y) Plot. Then click Align Axes → Proceed.

Next, you must provide a value limit, starting from X1 → X2 → Y1 → Y2. Then click Complete! to set the X-Axis and Y-Axis. Don't forget to tick the Log Scale → OK section.

In the next step, click Add Point (A), then select the desired curve (in this case using only LPG and Propane). Don't forget to look for coordinate points that overlap each other as shown in the following image.

Then, click View Data to find out the value of the coordinate point that was selected earlier. For example, as shown in the image below.

In the final step, the coordinate data above is then entered into the code in the #define section of the Arduino IDE.

#define x1_Value 199.150007852152
#define x2_Value 797.3322752256328
#define y1_Value 1.664988323698715
#define y2_Value 0.8990240080541785
#define x_Value 497.4177875376839
#define y_Value 1.0876679972710004

Then upload the program.   ~ DONE... , GOOD LUCK ~