some changes

lib/sensor/sensor.cpp

@@ -0,0 +1,27 @@
+#include "sensor.hpp"
+#include <Arduino.h>
+
+Sensor::Sensor()
+{}
+
+void Sensor::init(const uint8_t pin)
+{
+    _pin = pin;
+    pinMode(_pin, INPUT);
+    digitalWrite(_pin, HIGH);
+}
+
+float Sensor::get_value()
+{
+    /*
+    float sensor_volt;
+    float RS_gas; // Get value of RS in a GAS
+    float ratio; // Get ratio RS_GAS/RS_air
+    int sensorValue = analogRead(A0);
+    sensor_volt=(float)sensorValue/1024*5.0;
+    RS_gas = (5.0-sensor_volt)/sensor_volt; // omit *RL
+    //-Replace the name "R0" with the value of R0 in the demo of First Test 
+    ratio = RS_gas/R0;  // ratio = RS/R0
+    */
+    return ((analogRead(_pin))/1024*5.0);
+}

lib/sensor/sensor.hpp

@@ -0,0 +1,17 @@
+#ifndef HEADER_SENSOR
+#define HEADER_SENSOR
+
+#include <Arduino.h>
+
+constexpr uint8_t SENSOR_PIN = 36;
+
+class Sensor {
+public:
+    Sensor();
+    void init(const uint8_t pin);
+    float get_value();
+private:
+    uint8_t _pin;
+};
+
+#endif // HEADER_SENSOR

src/main.cpp

@@ -4,6 +4,8 @@
 #include <Adafruit_GFX.h>
 #include <Adafruit_SSD1306.h>
 
+#include "sensor.hpp"
+
 #define SCREEN_WIDTH 128
 #define SCREEN_HEIGHT 64
 
@@ -13,6 +15,8 @@ Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
 // RN2483Serial using RX2 and TX2
 HardwareSerial RN2483Serial(2);
 
+Sensor gaz_sensor;
+
 void printSSD1306(String text) {
   display.clearDisplay();
   display.setCursor(0, 0);
@@ -92,6 +96,7 @@ void setup() {
 
   // Initialize RN2483A Serial communication
   RN2483Serial.begin(57600);
+  Serial.begin(115200);
 
   // Initialize SSD1306
   Init_SSD1306();
@@ -99,6 +104,8 @@ void setup() {
 
 void loop() {
   test_RN2483A();
+  Serial.print("Value from sensor: ");
+  Serial.println(gaz_sensor.get_value());
   delay(1000);
 
   // Test communication to gateway