import machine
import time
import dht
from machine import Pin, PWM

#DHT22 Setup
#Connect the DHT22 sensor's VCC to 3.3V, GND to GND, and Data pin to GP2
dht_sensor = dht.DHT22(machine.Pin(2))
#Ultrasonic Sensor Setup (HC-SR04)
#Connect the ultrasonic sensor's VCC to 3.3V, GND to GND, Trigger pin to GP28 and Echo pin to GP27
trigger = Pin(28, Pin.OUT)
echo = Pin(27, Pin.IN)

#Servo Motor Setup (SG90)
#Connect the servo's VCC to 3.3V, GND to GND and Signal pin to GP16
#PWM operating frequency
servo = PWM(Pin(16))
servo.freq(50)  

#Function to control the servo motor the opeining and closing 
#Connect Servo motor signal to GP16
def set_servo_angle(angle):
    #Calculate the duty cycle for the servo motor 
    #Convert angle to duty cycle for PWM signal
    #Set the 16-bit duty cycle
    duty = 1000 + (angle / 180) * 1000  
    servo.duty_u16(int(duty * 65535 / 20000))  

#Function to calculate distance from the ultrasonic sensor (HC-SR04)
def measure_distance():
    #Send a 10 microsecond pulse to trigger the ultrasonic sensor
    trigger.low()  #Ensure the trigger pin is low
    time.sleep_us(2)  #Wait for 2 microseconds
    trigger.high()  #Set the trigger pin high
    time.sleep_us(10)  #Hold the trigger high for 10 microseconds
    trigger.low()  #Set the trigger pin low again

    #Measure the time it takes for the echo to return
    while echo.value() == 0:
        pulse_start = time.ticks_us()  #Record the time when the pulse was sent

    while echo.value() == 1:
        pulse_end = time.ticks_us()  #Record the time when the pulse returned

    #Calculate the duration of the pulse and convert to distance in cm
    pulse_duration = pulse_end - pulse_start
    distance = (pulse_duration * 0.0343) / 2  #Convert time to distance using the speed of sound

    return distance

#Main loop
while True:
    #Measure distance using the ultrasonic sensor
    distance = measure_distance()
    print(f"Distance: {distance} cm")  # Print the distance in centimeters

    #If the distance is less than 50 cm, open the garage door
    if distance < 50:  #If object is within 50 cm, open the door
        print("Garage door open")
        set_servo_angle(90)  #Rotate the servo motor to 90 degrees (open door)
    else:
        print("Garage door closed")
        set_servo_angle(0)  # Rotate the servo motor back to 0 degrees (close door)

    # Read temperature and humidity from the DHT22 sensor
    try:
        dht_sensor.measure()  # Take a reading from the DHT22 sensor
        temperature = dht_sensor.temperature()  #Get temperature reading in Celsius
        humidity = dht_sensor.humidity()  #Get humidity reading in percentage
        print(f"Temperature: {temperature}C, Humidity: {humidity}%")  # Print the readings
    except OSError as e:
        print("Failed to read sensor data.")  #Error handling in case of failure to read from the sensor

    time.sleep(2)  # Wait for 2 seconds before taking the next reading