from machine import Pin, ADC
from utime import sleep
import uasyncio as asyncio
from lcd1602 import LCD
from hcsr04 import HCSR04

lcd = LCD()

pot_pin = ADC(Pin(28))  
button_pin = Pin(16, Pin.IN, Pin.PULL_UP)  
green_led = Pin(13, Pin.OUT)  
red_led = Pin(12, Pin.OUT)    

ultrasonic_sensor = HCSR04(trigger_pin=2, echo_pin=3)  

DIST_MIN = 10
DIST_MAX = 100
LCD_MESSAGE_DELAY = 2 

threshold_distance = 50  

def get_pot_value():
    return int((pot_pin.read_u16() / 65535) * (DIST_MAX - DIST_MIN) + DIST_MIN)

async def get_distance():
    try:
        distance = ultrasonic_sensor.distance_cm()
        return distance
    except OSError:
        return None

async def display_startup_message():
    lcd.clear()
    lcd.write(0, 0, "Distance Counter")
    await asyncio.sleep(LCD_MESSAGE_DELAY)

async def blink_green_led():
    await asyncio.sleep(LCD_MESSAGE_DELAY)
    while True:
        green_led.value(1)
        await asyncio.sleep(0.1)
        green_led.value(0)
        await asyncio.sleep(0.1)

async def standby_mode():
    global threshold_distance

    while True:
        pot_value = get_pot_value()
        lcd.clear()
        lcd.write(0, 0, "User Input")
        lcd.write(0, 1, f"Dist: {pot_value} cm")
        await asyncio.sleep(0.5)  

        if not button_pin.value():  
            await asyncio.sleep(0.2)  

            if not button_pin.value():  
                return pot_value

async def scan_mode(threshold):
    while True:
        distance = await get_distance()

        if distance is not None:
            lcd.clear()
            lcd.write(0, 0, f"Distance: {int(distance)} cm")
            object_present = "Yes" if distance < threshold else "No"
            lcd.write(0, 1, f"Object: {object_present}")

            if distance < threshold:
                red_led.value(1)
            else:
                red_led.value(0)
        else:
            lcd.clear()
            lcd.write(0, 0, "Error")
            lcd.write(0, 1, "Out of range")

        await asyncio.sleep(0.5) 

        if not button_pin.value():  
            await asyncio.sleep(0.2)  
            
            if not button_pin.value():  
                red_led.value(0)
                return  

async def main():
    await display_startup_message()  

    while True:
        threshold = await standby_mode()  
        await scan_mode(threshold)  

loop = asyncio.get_event_loop()
loop.create_task(blink_green_led()) 
loop.create_task(main())  
loop.run_forever()