from machine import Pin, I2C
import utime
from lcd_api import LcdApi
from pico_i2c_lcd import I2cLcd

trigger = Pin(7, Pin.OUT)
echo = Pin(6, Pin.IN)

i2c = I2C(0, sda=Pin(20), scl=Pin(21), freq=400000)
I2C_ADDR = 0x27
lcd = I2cLcd(i2c, I2C_ADDR, 2, 16)

distance = 0
def ultrasound():
    global distance
    trigger.low()
    utime.sleep_us(2)
    trigger.high()
    utime.sleep_us(5)
    trigger.low()
    while echo.value() == 0:
        signaloff = utime.ticks_us()
    while echo.value() == 1:
        signalon = utime.ticks_us()
    timepassed = signalon - signaloff
    distance = (timepassed * 0.0343) / 2

while True:
    ultrasound()
    lcd.clear()
    lcd.putstr("Distance: {:.2f} cm".format(distance))
    utime.sleep(1)