#import libraries
import machine
import time
import dht
from machine import Pin

#Set up DHT22 sensor (Temperature and Humidity)
#Data pin connected to GP6 
dht_sensor = dht.DHT22(Pin(6))

#Set up PIR Motion Sensor
#OUT pin connected to GP28 
pir_sensor = Pin(28, Pin.IN)

# Set up Relay Module
# IN pin connected to GP18 
# The relay controls the conveyor belt motor (ON/OFF)
relay = Pin(18, Pin.OUT)
relay.value(0)  # Initially, the conveyor belt is running (relay OFF)

# Variables for counting and sensor readings
product_count = 0  #Keeps track of the number of products detected by PIR
pir_state = 0  #Stores the previous PIR state to avoid multiple counts
temp_low = 15.0  # Lower limit for temperature (in degrees Celsius)
temp_high = 30.0  # Upper limit for temperature (in degrees Celsius)
humidity_low = 40.0  # Lower limit for humidity (in percentage)
humidity_high = 60.0  # Upper limit for humidity (in percentage)

# Function to stop the conveyor belt by activating the relay
def stop_belt():
    relay.value(1)  # Activate relay to stop the belt
    print("Belt stopped due to abnormal conditions!") 

# Function to start the conveyor belt by deactivating the relay
def start_belt():
    relay.value(0)  # Deactivate relay to run the belt
    print("Belt operating normally.") 

# Main loop to continuously monitor the sensors and control the belt
while True:
    # Read PIR Sensor to detect product motion
    current_pir_state = pir_sensor.value()
    
    # If motion is detected (PIR value = 1), and it wasn't detected previously
    if current_pir_state == 1 and pir_state == 0:
        product_count += 1  # Increment product count
        print(f"Product Count: {product_count}")  # Display the count
        pir_state = 1  # Update PIR state to avoid double counting
        time.sleep(0.5)  # Small delay to debounce PIR sensor
    elif current_pir_state == 0:
        pir_state = 0  # Reset PIR state if no motion is detected

    # Read Temperature and Humidity from DHT22 sensor
    try:
        dht_sensor.measure()  # Measure temperature and humidity
        temperature = dht_sensor.temperature()  # Get temperature reading
        humidity = dht_sensor.humidity()  # Get humidity reading
        print(f"Temperature: {temperature:.1f}C, Humidity: {humidity:.1f}%")  # Display readings
    except OSError as e:
        print("Failed to read DHT22 sensor.")  # Handle sensor reading error
        temperature = None  # Set temperature to None if error occurs
        humidity = None  # Set humidity to None if error occurs

    # Check environmental conditions and control the conveyor belt
    if temperature is not None and humidity is not None:
        # If temperature or humidity is out of the defined range, stop the belt
        if (temperature < temp_low or temperature > temp_high or
            humidity < humidity_low or humidity > humidity_high):
            stop_belt()
        else:
            start_belt()  # If conditions are normal, keep the belt running

    time.sleep(2)  # Wait 2 seconds before the next loop iteration