/*
AM312 IR sensor with latching to hold the motion detected a bit longer(5000 0r 5 sec).
Simulation is included but for demonstration only and should be removed that part for real world.
*/
const int sensorLedPin = 12;  // Indicates sensor state ON: motion detected, OFF: motion stopped
const int triggerPin = 2;     // Pin connected to the AM312 PIR sensor
const int latchPin = 3;       // Pin to be latched HIGH for 5 seconds
const int sensorPowerPin = 4; // Pin to control the power to the sensor (optional)

bool latchState = false;      // Tracks if the latch is active
unsigned long latchStartTime = 0;   // Records the time when latch started
unsigned long latchDuration = 5000; // Duration for which the pin should stay HIGH (5 sec)

// for simulation only ------------
unsigned long startSimulation = 0;
unsigned long endSimulation = 5500;
// ------------------------------

void setup() {
  pinMode(sensorLedPin, OUTPUT);    // ON: motion detected, OFF: motion stopped
  pinMode(latchPin, OUTPUT);
  pinMode(triggerPin, INPUT);
  pinMode(sensorPowerPin, OUTPUT);  // Control pin for the sensor
  digitalWrite(latchPin, LOW);      // Initialize the latch pin to LOW
  digitalWrite(sensorPowerPin, HIGH); // Ensure the sensor is powered on initially

  Serial.begin(9600);

  // for simulation only ----
  startSimulation = millis();
  //-------------------------
}

void loop() {

  // WOKWi Simulation ONLY ---------------------------------------------------
  if (millis() - startSimulation >= endSimulation){
    digitalWrite(triggerPin, HIGH); // Simulate sensor trigger
    activateSensor();
    // Reset the simulation timer after activating the sensor
    startSimulation = millis();
  } else {
    digitalWrite(triggerPin, LOW); // Ensure the trigger pin goes LOW otherwise
  }
  // --------------------------------------------------------------------------
  
}

void activateSensor(){

  // Check the sensor input (only if latch is not active)
  if (!latchState && digitalRead(triggerPin) == HIGH) {
    digitalWrite(sensorLedPin, HIGH); 
    Serial.println("Motion detected!");
    Serial.println("Start latching time...");
    latchState = true;  // Activate latch state
    latchStartTime = millis();  // Record the time latch started
    digitalWrite(latchPin, HIGH);  // Set the latch pin HIGH
    digitalWrite(sensorPowerPin, LOW); // Disable the sensor (optional)
    
    delay(1000); // Allow the sensor to power down
  }

  // Check if the latch is active and if the duration has passed
  if (latchState && (millis() - latchStartTime >= latchDuration)) {
    latchState = false;  // Deactivate latch state
    digitalWrite(latchPin, LOW);  // Set the latch pin LOW after 5 sec
    digitalWrite(sensorPowerPin, HIGH); // Re-enable the sensor (optional)
    digitalWrite(sensorLedPin, LOW); // Turn off the sensor LED explicitly
    Serial.println("Motion stopped after latch time.");    
  }
}