Simple IoT Auto Light with Motion Sensor and Cayenne

#define CAYENNE_PRINT Serial  // Comment this out to disable prints and save space
#include "CayenneDefines.h"
#include "CayenneWiFi.h"
#include "CayenneWiFiClient.h"
#define RELAY_PIN 5

// Cayenne authentication token. This should be obtained from the Cayenne Dashboard.
char token[] = ""; // Insert your token here
char ssid[] = ""; // Insert your SSID here
char pwd[] = ""; // Insert your SSID password here

// Virtual Pin of the Digital Motion Sensor widget.
#define VIRTUAL_PIN V12

// Digital pin the motion sensor is connected to. Do not use digital pins 0 or 1 since those conflict with the use of Serial.
const int motionSensorPin = 4;

void setup()
{
  Serial.begin(115200);
  Cayenne.begin(token, ssid, pwd);
  pinMode(RELAY_PIN, OUTPUT);

}

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 = digitalRead(motionSensorPin);
    if (currentState != previousState) {
      Cayenne.virtualWrite(VIRTUAL_PIN, currentState);
      previousState = currentState;
    }
        previousMillis = currentMillis;
  }
}

CAYENNE_IN(V21)
{
  // get value sent from dashboard
  int currentValue = getValue.asInt(); // 0 to 1

  // assuming you wire your relay as normally open
  if (currentValue == 0) {
    digitalWrite(RELAY_PIN, HIGH);
  } else {
    digitalWrite(RELAY_PIN, LOW);
  }
}