'''

Voltaat Learn (http://learn.voltaat.com)

Link to the full tutorial:

Tutorial: automatic_opening_gate_for_a_car_garage.

This code opens the garage gate automatically using

a servo motor when a car passes in front of the garage

and displays whether the gate is open or not on the LCD screen..

Note: You can use this sketch with any Raspberry Pi Pico.

'''

import machine

from machine import Pin, I2C

import utime

from servo import Servo

from lcd_api import LcdApi

from pico_i2c_lcd import I2cLcd

# Initialize the LCD screen

I2C_ADDR = 0x27

I2C_NUM_ROWS = 2

I2C_NUM_COLS = 16

i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)

lcd = I2cLcd(i2c, I2C_ADDR, I2C_NUM_ROWS, I2C_NUM_COLS)

# Initialize the ultrasonic sensor

trig = Pin(28, Pin.OUT)

echo = Pin(27, Pin.IN)

# Initialize the servo motor using the Servo library

my_servo = Servo(pin_id=16)   # Use GP16 pin for the servo motor

# Function to calculate the distance

def get_distance():

   trig.low()

   utime.sleep_us(2)

   trig.high()

   utime.sleep_us(10)

   trig.low()

   start = 0

   end = 0

   while echo.value() == 0:

       start = utime.ticks_us()

   while echo.value() == 1:

       end = utime.ticks_us()

   duration = utime.ticks_diff(end, start)

   distance = (duration * 0.0343) / 2  # cm

   return distance

# Main function

def main():

   lcd.clear()

   lcd.putstr("  System Ready")

   my_servo.write(90)   # Close the gate initially

   utime.sleep(2)

   lcd.clear()

   while True:

       dist = get_distance()

       lcd.move_to(0, 0)

       if dist <= 25:  # If an object (e.g., a car) is detected nearby

           lcd.putstr(" Gate is opened")

           my_servo.write(180)   # Open the gate

           utime.sleep(3)

       else:

           lcd.putstr(" Gate is closed")

           my_servo.write(90)    # Close the gate

       utime.sleep(0.5)

       lcd.clear()

# Run the program

main()

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