# Imports
import onewire, ds18x20, time
from machine import Pin, PWM

# Set up the LED pins
red = Pin(18, Pin.OUT)
amber = Pin(19, Pin.OUT)
green = Pin(20, Pin.OUT)

# Set up the Buzzer pin as PWM
buzzer = PWM(Pin(13))

# Start PWM duty to 0% at program start
buzzer.duty_u16(0)
 
# Set the data pin for the sensor
SensorPin = Pin(26, Pin.IN)
 
# Tell MicroPython that we're using a DS18B20 sensor, and which pin it's on
sensor = ds18x20.DS18X20(onewire.OneWire(SensorPin))

# Look for DS18B20 sensors (each contains a unique rom code)
roms = sensor.scan()

def alarm(): # Our alarm function
    
    buzzer.duty_u16(10000) # Buzzer duty (volume) up

    for i in range(5): # Run this 5 times
        
        buzzer.freq(5000) # Higher pitch
        
        # LEDs ON
        red.value(1)
        amber.value(1)
        green.value(1)
        
        time.sleep(0.2) # wait 1 second
        
        buzzer.freq(1000) # Lower pitch
        
        # LEDs OFF
        red.value(0)
        amber.value(0)
        green.value(0)        
        
        time.sleep(0.2) # wait 1 second

    buzzer.duty_u16(0) # Buzzer duty (volume) off 

while True: # Run forever
  
    time.sleep(5) # Wait 5 seconds between readings
  
    for rom in roms: # For each sensor found (just 1 in our case)
    
        sensor.convert_temp() # Convert the sensor units to centigrade
        time.sleep(1) # Always wait 1 second after converting
    
        reading = sensor.read_temp(rom) # Take a temperature reading
    
        print(reading) # Print the reading

        if reading < 25: # If reading is less than or equal to 18
         
            alarm() # Call our alarm function