import machine
import time

# 1. Pin Configuration
trig = machine.Pin(5, machine.Pin.OUT)
echo = machine.Pin(18, machine.Pin.IN)

# Setup a clean hardware PWM channel on Pin 13
servo_pin = machine.Pin(13)
servo = machine.PWM(servo_pin)
servo.freq(50)  # Standard frequency for SG90 servo

def get_distance():
    trig.off()
    time.sleep_us(2)
    trig.on()
    time.sleep_us(10)
    trig.off()
    
    duration = machine.time_pulse_us(echo, 1, 30000)
    if duration < 0: 
        return 999
    return (duration * 0.034) / 2

def set_angle(angle):
    # Precise duty cycle mapping (40 = 0 degrees, 115 = 90 degrees)
    duty_value = int(((angle / 180) * 150) + 40)
    servo.duty(duty_value)

# System Initialization Reset
set_angle(0)
time.sleep(0.5)

print("✨ Hardware Loop Reset Complete! ✨")
print("Drag the green ultrasonic sensor slider back and forth to test.")

while True:
    dist = get_distance()
    print("Live Distance Reading:", round(dist, 1), "cm")
    
    if 0 < dist < 20:
        print("🔓 Object Detected! Lifting Gate Arm Up (90°)...")
        set_angle(90)
    else:
        print("🔒 Way Cleared. Lowering Gate Arm Down (0°)...")
        set_angle(0)
        
    time.sleep(0.2)