print("this program will integrate ESP32 with ultrasonic sensor")
#import necessary modules/libraries
import hcsr04 #ultrasonic library
import ssd1306 #oled library
from utime import sleep
from machine import SoftI2C, Pin, PWM
#Create an object called ultrasonic_sensor using OOP (object oreinted programming)
#OOP format is --> library name.class(......)
ultrasonic_sensor = hcsr04.HCSR04(trigger_pin=13, echo_pin=27, echo_timeout_us=500*2*30)

#declare pin on OLED display
i2c_oled = SoftI2C(scl=Pin(22), sda=Pin(21))
oled_width = 128 #based on spec
oled_height = 64 #based on spec

#create an object called "oled"
#remark : object format "library name & class name"
oled = ssd1306.SSD1306_I2C(oled_width, oled_height, i2c_oled)

#Declare buzzer connection
buzzer = PWM(Pin(23, Pin.OUT))

while True:

    #Let's test our ultrasonic sensor
    jarak_in_cm = ultrasonic_sensor.distance_cm() #use when you need decimal point
    jarak_in_mm = ultrasonic_sensor.distance_mm() #use when you want whole number

    #Display the distance values on serial monitor 
    print('An object is detected in :', jarak_in_cm, 'cm')
    print('An object is detected in :', jarak_in_mm, 'mm')
    print('------------------------------------------------')
    print('\n')

    #Display distance value on OLED screen 
    oled.fill(1)
    oled.text('Distance ditected:', 3, 0, 0)
    oled.text(str(jarak_in_cm), 5, 20, 0)
    oled.text('cm', 75, 20, 0)
    oled.text(str(jarak_in_mm), 5, 40, 0)
    oled.text('mm', 75, 40, 0)
    
    oled.show()

    if jarak_in_cm < 50:
        for i in range (10):
            buzzer.init(freq=1700, duty=400)
            sleep(0.5)
            buzzer.init(freq=1, duty=0)
            sleep(0.5)
        buzzer.init(freq=1000, duty=512)
    elif 50<= jarak_in_cm < 150:
        for i in range (10):
            buzzer.init(freq=1700, duty=400)
            sleep(1)
            buzzer.init(freq=1, duty=0)
            sleep(1)
    else:
        buzzer.init(freq=1, duty=0)


    sleep(5)