from machine import Pin, PWM, time_pulse_us
import time

# =========================
# LCD PINS
# =========================

rs = Pin(16, Pin.OUT)
en = Pin(17, Pin.OUT)

d4 = Pin(18, Pin.OUT)
d5 = Pin(19, Pin.OUT)
d6 = Pin(20, Pin.OUT)
d7 = Pin(21, Pin.OUT)

# =========================
# OUTPUTS
# =========================

led = Pin(14, Pin.OUT)
buzzer = Pin(5, Pin.OUT)

# =========================
# SERVO
# =========================

servo = PWM(Pin(4))
servo.freq(50)

def set_angle(angle):

    min_us = 500
    max_us = 2500

    pulse = min_us + (max_us - min_us) * angle / 180

    duty = int(pulse * 65535 / 20000)

    servo.duty_u16(duty)

# =========================
# INPUTS
# =========================

switch = Pin(15, Pin.IN, Pin.PULL_DOWN)

dips = [
    Pin(6, Pin.IN, Pin.PULL_UP),
    Pin(7, Pin.IN, Pin.PULL_UP),
    Pin(8, Pin.IN, Pin.PULL_UP),
    Pin(9, Pin.IN, Pin.PULL_UP),
    Pin(10, Pin.IN, Pin.PULL_UP),
    Pin(11, Pin.IN, Pin.PULL_UP),
    Pin(12, Pin.IN, Pin.PULL_UP),
    Pin(13, Pin.IN, Pin.PULL_UP)
]

# =========================
# HC-SR04
# =========================

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

# =========================
# LCD FUNCTIONS
# =========================

def pulse():
    en.value(1)
    time.sleep_us(40)
    en.value(0)
    time.sleep_us(40)

def send4(value):

    d4.value((value >> 0) & 1)
    d5.value((value >> 1) & 1)
    d6.value((value >> 2) & 1)
    d7.value((value >> 3) & 1)

    pulse()

def send(value, mode):

    rs.value(mode)

    send4(value >> 4)
    send4(value & 0x0F)

def cmd(c):

    send(c, 0)
    time.sleep_ms(2)

def write(text):

    for ch in text:
        send(ord(ch), 1)

def clear():

    cmd(0x01)

def lcd_init():

    time.sleep_ms(50)

    send4(0x03)
    time.sleep_ms(5)

    send4(0x03)
    time.sleep_ms(5)

    send4(0x03)
    time.sleep_ms(5)

    send4(0x02)

    cmd(0x28)
    cmd(0x0C)
    cmd(0x06)
    cmd(0x01)

# =========================
# DISTANCE FUNCTION
# =========================

def get_distance():

    trig.low()
    time.sleep_us(2)

    trig.high()
    time.sleep_us(10)
    trig.low()

    duration = time_pulse_us(echo, 1, 30000)

    if duration < 0:
        return 999

    distance = duration / 58

    return distance

# =========================
# DIP SWITCH FUNCTION
# =========================

def read_dip():

    value = ""

    for d in dips:
        value += str(1 - d.value())

    return value

# =========================
# START LCD
# =========================

lcd_init()

set_angle(0)

# =========================
# MAIN LOOP
# =========================

while True:

    if switch.value() == 0:

        led.off()
        buzzer.off()

        set_angle(0)

        clear()
        write("SYSTEM OFF")

        time.sleep(1)

        continue

    if read_dip() != "10000000":

        led.off()
        buzzer.off()

        set_angle(0)

        clear()
        write("SET MODE")

        time.sleep(1)

        continue

    dist = get_distance()

    clear()

    if dist < 30:

        led.on()

        buzzer.on()

        set_angle(90)

        write("ROOM OCCUPIED")

        cmd(0xC0)

        write("LIGHT ON")

    else:

        led.off()

        buzzer.off()

        set_angle(0)

        write("ROOM EMPTY")

        cmd(0xC0)

        write("LIGHT OFF")

    print("Distance:", dist)

    time.sleep(1)