/******************************
  Author: Hay Chhuy
  AM312 Sensor Code
  Version: 1.0
  Date: 29/08/2024
  Last Update: Initial Version
******************************/

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)

void setup() {
  pinMode(sensorLedPin, OUTPUT); // ON: motion detected, OFF: motion stopped
  
  /***** for simulation where we enforce the AM312 sensor pin2 to HIGH
  to do it, we need to alter the pin2 as OUTPUT not INPUT! ***********/
  
  //pinMode(triggerPin, INPUT);
  pinMode(latchPin, OUTPUT); // **** to be commented out when release
  pinMode(triggerPin, OUTPUT); // **** to be commented out when release

  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);

}

void loop() {

  digitalWrite(triggerPin,HIGH);

  // Check the sensor input (only if latch is not active)
  if (!latchState) {
    if (digitalRead(triggerPin) == HIGH) {
      digitalWrite(sensorLedPin, HIGH); 
      Serial.println("Motion detected!");
      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
    } else {
      digitalWrite(sensorLedPin, LOW); 
      // Uncomment the next line if you want to see "Motion stopped!" when no motion is detected
      Serial.println("Motion stopped!");
    }
  }

  //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)
    Serial.println("Motion stopped after latch time.");
  }
}