from machine import Pin, time_pulse_us
from time import sleep_us, sleep

# Define pins
pir_pin = Pin(27, Pin.IN)
trig_pin = Pin(5, Pin.OUT)
echo_pin = Pin(18, Pin.IN)

# Initialize variables
visitor_count = 0
prev_distance = 0
motion_detected = False

def measure_distance():
    """Measure distance using ultrasonic sensor"""
    trig_pin.off()
    sleep_us(2)
    trig_pin.on()
    sleep_us(10)
    trig_pin.off()
    
    duration = time_pulse_us(echo_pin, 1, 30000)  # wait for echo, timeout=30ms
    distance = (duration / 2) / 29.1  # convert to cm
    return distance

print("Visitor Counter System Started...")

while True:
    motion = pir_pin.value()
    distance = measure_distance()
    
    if motion:
        print("Motion Detected! Checking distance...")
        sleep(0.2)
        
        new_distance = measure_distance()
        
        # If distance changes significantly, assume a person passed
        if abs(new_distance - prev_distance) > 15:  # threshold in cm
            visitor_count += 1
            print("Person Detected! Total Visitors:", visitor_count)
            sleep(2)  # wait to avoid double counting
        
        prev_distance = new_distance
    
    sleep(0.5)