from machine import Pin, I2C
from ssd1306 import SSD1306_I2C
import utime

trigger1 = Pin(26, Pin.OUT)
echo1 = Pin(27, Pin.IN)
trigger2 = Pin(21, Pin.OUT)
echo2 = Pin(20, Pin.IN)
trigger3 = Pin(19, Pin.OUT)
echo3 = Pin(18, Pin.IN)

i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)
oled = SSD1306_I2C(128, 64, i2c, addr=0x3C) 
def ultra(trigger, echo):
    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
    return distance

def display_status(distance):
    if distance > 200:
        status = "Free"
    else:
        status = "In Use"
    return status

while True:
    distance1 = ultra(trigger1, echo1)
    distance2 = ultra(trigger2, echo2)
    distance3 = ultra(trigger3, echo3)

    status1 = display_status(distance1)
    status2 = display_status(distance2)
    status3 = display_status(distance3)

    oled.fill(0) 
    oled.text("Slot 1: " + status1, 0, 10)
    oled.text("Slot 2: " + status2, 0, 30)
    oled.text("Slot 3: " + status3, 0, 50)


    oled.show()