from machine import Pin, time_pulse_us
import time
from lcd1602 import LCD

lcd=LCD()

# LEDs
led1 = Pin(13, Pin.OUT)
led2 = Pin(14, Pin.OUT)
led3 = Pin(15, Pin.OUT)

# Buzzer
buzzer = Pin(16, Pin.OUT)

# Ultrasonic pins
trig = Pin(3, Pin.OUT)
echo = Pin(2, Pin.IN)

def get_distance():
    # Send trigger pulse
    trig.low()
    time.sleep_us(2)
    trig.high()
    time.sleep_us(10)
    trig.low()

    # Measure echo pulse width
    duration = time_pulse_us(echo, 1, 30000)  # timeout 30ms

    if duration < 0:
        return None  # no reading

    # Convert to distance (cm)
    distance = (duration * 0.0343) / 2
    return distance

while True:
    dist = get_distance()

    if dist is None:
        print("No reading")
        led1.off(); led2.off(); led3.off()
        buzzer.off()
        time.sleep(2.5)
        continue

    print("Distance:", dist, "cm")

    # LED logic
    if dist < 10:
        led1.toggle(); led2.on(); led3.on()
        buzzer.toggle()
        lcd.write(0,0,'DANGER:Step away')
        lcd.write(0,1,'from the device!')
    elif dist < 20:
        led1.off(); led2.on(); led3.on()
        buzzer.off()
        lcd.write(0,0,'You are           ')
        lcd.write(0,1,'too close!        ')
    elif dist < 30:
        led1.off(); led2.off(); led3.on()
        buzzer.off()
        lcd.write(0,0,'You have entered' )
        lcd.write(0,1,'a restricted zone.')
    else:
        led1.off(); led2.off(); led3.off()
        buzzer.off()
        lcd.write(0,0,'                 ')
        lcd.write(0,1,'                 ')
    time.sleep(0.1)