import machine
import ssd1306
import time

# Initialize the OLED display
i2c = machine.I2C(scl=machine.Pin(22), sda=machine.Pin(21))
oled = ssd1306.SSD1306_I2C(128, 64, i2c)

# Initialize the ultrasonic sensor (HC-SR04)
# Trigger pin connected to pin 4, echo pin connected to pin 5
trigger_pin = machine.Pin(4, machine.Pin.OUT)
echo_pin = machine.Pin(5, machine.Pin.IN)

# Initialize the buzzer (change pin number accordingly)
buzzer_pin = machine.Pin(18, machine.Pin.OUT)

def read_distance():
    # Send a 10us pulse to trigger the sensor
    trigger_pin.value(1)
    time.sleep_us(10)
    trigger_pin.value(0)
    
    # Measure the duration of the echo pulse
    while echo_pin.value() == 0:
        pulse_start = time.ticks_us()
    while echo_pin.value() == 1:
        pulse_end = time.ticks_us()
    
    # Calculate the pulse duration and convert it to distance (in cm)
    pulse_duration = time.ticks_diff(pulse_end, pulse_start)
    distance = pulse_duration * 0.034 / 2  # Speed of sound in air is approximately 0.034 cm/μs
    return distance

def display_distance(distance):
    oled.fill(0)
    oled.text("Distance: {:.2f} cm".format(distance), 0, 0)
    oled.show()

def activate_buzzer():
    # Activate buzzer
    buzzer_pin.on()

def deactivate_buzzer():
    # Deactivate buzzer
    buzzer_pin.off()

while True:
    distance = read_distance()
    display_distance(distance)
    
    if distance < 100:
        activate_buzzer()
    else:
        deactivate_buzzer()
    
    time.sleep(1)  # Update every second