import time
import utime
time.sleep(0.1)
from machine import Pin

def ultra_fb(t, e, position): #for front and back
    trigger = Pin(t, Pin.OUT)
    echo = Pin(e, Pin.IN)
    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
    distance = "{:.1f}".format(distance)
    if float(distance) <= 100:
        if float(distance) >= 50:
            print("Obstacle is approaching on " + position)
        else:
            print("Obstacle is very close on " + position + ", be careful")

def ultra_s(t, e, position): #for sides
    trigger = Pin(t, Pin.OUT)
    echo = Pin(e, Pin.IN)
    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
    distance = "{:.1f}".format(distance)
    if float(distance) <= 50:
        if float(distance) >= 25:
            print("Obstacle is approaching on " + position)
        else:
            print("Obstacle is very close on " + position + ", be careful")

while True:
    ultra_fb(0, 1, "front") #front
    ultra_s(21, 20, "right") #right
    ultra_s(26, 27, "left") #left
    ultra_fb(14, 15, "back") #back