print('Reverse sensor')
print('Created by: Ruzaini')
print('Date: 9/11/2024')

# Import libraries/modules
import ultrasonic_library
from machine import Pin, PWM
from utime import sleep

# Pin Declaration
trig_pin = Pin(27, Pin.OUT)  # Trigger pin
ech_pin = Pin(26, Pin.IN)    # Echo pin
led_pin = Pin(4, Pin.OUT)    # Pin for LED
buzzer_pin = Pin(2, Pin.OUT) # Pin for Buzzer

# Object declaration for ultrasonic sensor
buzzer_pwm = PWM(buzzer_pin)
buzzer_pwm.duty(0)     # Start with no sound (duty cycle = 0%)
buzzer_pwm.freq(1000)   # Set initial frequency to 1000Hz (middle tone)

# Parameter declaration for ultrasonic sensor
ultrasonic_sensor = ultrasonic_library.HCSR04(trigger_pin=trig_pin, echo_pin=ech_pin)

# Main program
blink_interval_close = 0.04   # Interval time in seconds for blinking (close distance)
blink_interval_moderate = 0.2  # Interval time in seconds for blinking (moderate distance)
blink_interval_far = 0.5     # Interval time in seconds for blinking (far distance)

while True:
    # Get the distance from the ultrasonic sensor
    distance_from_wall = ultrasonic_sensor.distance_cm()  # Get distance in cm
    print('The car is', distance_from_wall, 'cm from the wall')
    print('--------------------------------------------------')

    # Set the buzzer sound based on distance (using if-else)
    if distance_from_wall <= 30:
        buzzer_pwm.freq(2000)  # High pitch for close distance
        buzzer_pwm.duty(1023)  # Loud sound
    elif distance_from_wall <= 65:
        buzzer_pwm.freq(1500)  # Medium pitch for moderate distance
        buzzer_pwm.duty(512)   # Moderate sound
    elif distance_from_wall <= 100:
        buzzer_pwm.freq(1300)  # Low pitch for far distance
        buzzer_pwm.duty(256)   # Soft sound
    else:
        buzzer_pwm.duty(0)     # No sound when far

    # Control LED and Buzzer Blink (using if-else)
    if distance_from_wall <= 30:  # Close range
        led_pin.on()    # Turn on LED
        buzzer_pwm.duty(512)  # Set buzzer to moderate sound (50% duty cycle)
        sleep(blink_interval_close)  # Wait for blink interval
        led_pin.off()   # Turn off LED
        buzzer_pwm.duty(0)  # Turn off buzzer
        sleep(blink_interval_close)  # Wait for blink interval
    elif distance_from_wall <= 65:  # Moderate range
        led_pin.on()    # Turn on LED
        buzzer_pwm.duty(512)  # Set buzzer to moderate sound (50% duty cycle)
        sleep(blink_interval_moderate)  # Wait for blink interval
        led_pin.off()   # Turn off LED
        buzzer_pwm.duty(0)  # Turn off buzzer
        sleep(blink_interval_moderate)  # Wait for blink interval
    elif distance_from_wall <= 100:  # Far range
        led_pin.on()    # Turn on LED
        buzzer_pwm.duty(256)  # Set buzzer to low sound (25% duty cycle)
        sleep(blink_interval_far)  # Wait for blink interval
        led_pin.off()   # Turn off LED
        buzzer_pwm.duty(0)  # Turn off buzzer
        sleep(blink_interval_far)  # Wait for blink interval
    else:  # Very far
        led_pin.off()   # Turn off LED
        buzzer_pwm.duty(0)  # Turn off buzzer
        sleep(1)