from machine import Pin, I2C
import ssd1306
import time

trigger = Pin(5, Pin.OUT)
echo = Pin(18, Pin.IN)

i2c = I2C(0, scl=Pin(22), sda=Pin(21))
oled = ssd1306.SSD1306_I2C(128, 64, i2c)

def distance():
    trigger.off()
    time.sleep_us(2)

    trigger.on()
    time.sleep_us(10)
    trigger.off()

    while echo.value() == 0:
        pass

    start = time.ticks_us()

    while echo.value() == 1:
        pass

    end = time.ticks_us()

    duration = end - start
    dist = (duration * 0.0343) / 2

    return dist

while True:
    d = distance()

    oled.fill(0)
    oled.text("Distance:", 0, 10)
    oled.text(str(d) + " cm", 0, 30)
    oled.show()

    time.sleep(1)