print("This is the program for Car Reverse Sensor System")
print("By Afiq Farhan for IoT BEB34303")

#STEP 1: IMPORT MODULES/LIBRARY FOR ULTRASONIC SENSOR, OLED LIBRARY AND OLED DISPLAY
import hsrc04 #import ultrasonic library
import sdl1306 #import OLED library
from machine import SoftI2C, PWM, Pin
from time import sleep

#STEP 2: DECLARE CONNECTION
#STEP 2.1: ULTRASONIC SENSOR
ultrasonic_sensor = hsrc04(trigger_pin=26, echo_pin=27, echo_timeout_us=500*2*30)

#STEP 2.2: OLED DISPLAY
oled_display = SoftI2C (scl=Pin(22), sda=Pin(22))
oled_width = 128
oled_height + 64
oled=ssd1306.SSD1306_I2C(oled_width, oled_height, oled_display)

#STEP 2.3: BUZZER
buzzer+PWM(Pin(23), Pin.OUT)

#STEP 3: PROCESS
while True:
    #for Ultrasonic sensor on the terminal
    distance_in_cm = ultrasonic_sensor.distance_cm()
    distance_in_mm = ultrasonic_sensor.distance_mm()

    print('An object is detected in: ', distance_in_cm, 'cm')
    print('An object is detected in: ', distance_in_mm, 'mm')

    #to display the distance on OLED
    oled.fill(1)
    oled.text('Object detected: ',3,0,0)
    oled.text(str(distance_in_cm),5,20,0) #Display in cm
    oled.text('cm',75,20,0)

    oled.text(str(distance_in_mm),5,40,0) #Display in mm
    oled.text('mm',75,40,0)
    oled.show()

    #Check the range
    if distance_in_cm<50
        for i in range(100):
            buzzer.init(freq=1400, duty=400)
            sleep(0.5)
            buzzer.init(freq=1, duty=0)
            sleep(0.5)

    elif 50<distance_in_cm<150
        for i in range(100):
            buzzer.init(freq=1400, duty=400)
            sleep(1)
            buzzer.init(freq=1, duty=0)
            sleep(1)

    else
        buzzer.init(freq=1, duty=0)

    sleep(5)