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

#define RL 10 // 10K ohm
#define Ro 0
#define Volt 5.0
#define ADC 1023.0 // maximum adc resolution on Arduino and ESP8266 development boards
#define x 0
#define x1 0
#define x2 0
#define y 0
#define y1 0
#define y2 0

void setup() {
  Serial.begin(9600); // default baudrate for the Arduino and ESP8266 development boards
  mq2.begin(); // initiate mq2 sensor

  // set calibration
  mq2.setCalibration(RL, Ro, Volt, ADC, x, x1, x2, y, y1, y2);
}

void loop() {  
  mq2.viewCalibrationData(); // print to serial monitor: data calibration
  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. An example is seen below :

#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 ~