#define CAYENNE_PRINT Serial  // Comment this out to disable prints and save space

// If you're not using the Ethernet W5100 shield, change this to match your connection type. See Communications examples.
#include <CayenneEthernet.h>

// Cayenne authentication token. This should be obtained from the Cayenne Dashboard.
char token[] = "xph6x521ur";

// Virtual Pin of the Smoke Sensor widget.
#define VIRTUAL_PIN V1

// Analog pin the Smoke Sensor is connected to. Do not use digital pins 0 or 1 since those conflict with the use of Serial.
const int smokeSensorPin = A0;

void setup()
{
  Serial.begin(9600);
  Cayenne.begin(token);
}

void loop()
{
  Cayenne.run();
  checkSensor();
}

int previousState = -1;
int currentState = -1;
unsigned long previousMillis = 0;

void checkSensor()
{
  unsigned long currentMillis = millis();
  // Check sensor data every 250 milliseconds
  if (currentMillis - previousMillis >= 250) {
    // Check the sensor state and send data when it changes.
    currentState = analogRead(smokeSensorPin);
    Cayenne.virtualWrite(VIRTUAL_PIN, currentState);
    previousMillis = currentMillis;
  }
}