print("Smart Water Quality Monitoring System using IoT")
print("Created by: MUIZ SALLEH")
print("25/4/2025")
print("Mini Project")

#import libraries/modules
from machine import Pin, PWM, SoftI2C, ADC
import ULTRASONIC_LIBRARY
import oled_library
from neopixel import NeoPixel
from time import sleep
import math

#Pin declaration
# ADC Inputs
# Potentiometer for pH level (GPIO27)
ph_sensor = ADC(Pin(27))
ph_sensor.atten(ADC.ATTN_11DB)
ph_sensor.width(ADC.WIDTH_10BIT)

# LDR (AO to GPIO13)
ldr = ADC(Pin(13))
ldr.atten(ADC.ATTN_11DB)
ldr.width(ADC.WIDTH_10BIT)

# Temperature sensor (NTC on GPIO26)
ntc = ADC(Pin(26))  # NTC Thermistor
ntc.atten(ADC.ATTN_11DB)
ntc.width(ADC.WIDTH_12BIT)

# Outputs
red_led = Pin(14, Pin.OUT)     # indicator water level
green_led = Pin(12, Pin.OUT)   # normal pH LED
yellow_led = Pin(32, Pin.OUT)  # Low pH LED
blue_led = Pin(25, Pin.OUT)    # High pH LED
buzzer = PWM(Pin(33), freq=1000)
np = NeoPixel(Pin(16), 16)

#Object declaration
# OLED Setup 
i2c = SoftI2C(scl=Pin(22), sda=Pin(21))
screen = oled_library.SSD1306_I2C(width=128, height=64, i2c=i2c)

# Ultrasonic Sensor 
TRIG = Pin(5, Pin.OUT)
ECHO = Pin(17, Pin.IN)
water_sensor = ULTRASONIC_LIBRARY.HCSR04(trigger_pin=TRIG, echo_pin=ECHO, timeout_us=30000)

#parameter declaration
# Servo Setup 
servo = PWM(Pin(18), freq=50)

# Function: Move Servo to angle 
def move_servo(angle):
    duty = int(((angle / 180) * 2 + 0.5) / 20 * 1023)
    servo.duty(duty)

#Function: read temperature using the Beta formula 
def read_temperature_celsius(samples=10):
    BETA = 3950
    total = 0
    for _ in range(samples):
        analog_value = ntc.read()
        total += analog_value
        sleep(0.01)  # Short delay between samples
    avg_value = total / samples

    resistance = 4095.0 / avg_value - 1
    temp_kelvin = 1 / (math.log(resistance) / BETA + 1.0 / 298.15)
    temp_celsius = temp_kelvin - 273.15
    return round(temp_celsius, 1)

# Main Program
while True:
    # Water level 
    measure_distance = water_sensor.distance_cm()
    print("Water level =", measure_distance, "cm")

    # LDR light level 
    light_value = ldr.read()
    lux = (1023 - light_value) * (1000 / 1023)
    print("Lux:", lux)

    # Potentiometer for pH level and LED
    pot_value = ph_sensor.read()
    ph_value = round((pot_value / 1023) * 14, 1)  # Scale to pH 0–14
    print("pH value:", ph_value)

    if ph_value < 15:
        ph_status = "Low"
        yellow_led.on()  # Turn on yellow LED for low pH
        green_led.off()
        blue_led.off()
    elif 15 <= ph_value <= 35:
        ph_status = "OK"
        yellow_led.off()  # Turn off yellow LED for normal pH
        green_led.on()    # Turn on green LED for normal pH
        blue_led.off()
    else:
        ph_status = "High"
        yellow_led.off()  # Turn off yellow LED for high pH
        green_led.off()
        blue_led.on()     # Turn on blue LED for high pH

    #Read Temperature (NTC Sensor)
    temp_c = read_temperature_celsius()

    # Display on OLED
    screen.fill(0)
    screen.text("Monitor 1", 0, 0)
    screen.text("Water: " + str(measure_distance) + "cm", 0, 10)
    screen.text("Lux: " + str(int(lux)), 0, 20)
    screen.text("pH: " + str(ph_value), 0, 30)
    screen.text("pH Status: " + ph_status, 0, 40)
    screen.text("Temp: {}C".format(temp_c), 0, 50)
    screen.show()

    # Buzzer if water level too high 
    if measure_distance > 300:
        red_led.on()
        buzzer.duty(1023)
    elif measure_distance < 150:
        red_led.on()
        buzzer.duty(1023)
    else:
        red_led.off()
        buzzer.duty(0)

    # Neopixel reacts to darkness
    if lux < 500:
        for i in range(16):
            np[i] = (255, 255, 255)
        np.write()
    else:
        for i in range(16):
            np[i] = (0, 0, 0)
        np.write()

    # Servo Temperature Control
    if temp_c >= 30:
        move_servo(90)
    else:
        move_servo(0)

    sleep(0.5)