from machine import Pin, Timer, I2C
from hcsr04 import HCSR04
from ssd1306 import SSD1306_I2C
i2c = I2C(sda = Pin(21), scl = Pin(22))
oled = SSD1306_I2C(128, 32, i2c)

sensor = HCSR04(trigger_pin = 2, echo_pin = 15, echo_timeout_us = 1000000)

def hcsr04_isr(event):
  distance = sensor.distance_cm()
  print (distance)
  print(round(distance,2))
  oled.text('Distance (cm.)', 0, 0)
  oled.text(str(round(distance, 2)) , 5, 20)
  oled.show()

blink_timer = Timer(1)
blink_timer.init(period = 5000, mode = Timer .PERIODIC, callback = hcsr04_isr)