from machine import Pin, ADC, Timer
import time
import math


button = Pin(14, Pin.IN, Pin.PULL_UP)  
led = Pin(15, Pin.OUT)                 
thermistor = ADC(26)                   

debounce_time = 200  
last_interrupt_time = 0

# Constants for NTC Thermistor
BETA = 3950            # Beta parameter
T0 = 298.15            # Reference temperature (25°C in Kelvin)
R0 = 10000             # Reference resistance at T0 (10k ohms)
R_DIVIDER = 10000      # Known resistor in the voltage divider (10k ohms)
VCC = 3.3              # Supply voltage

def read_temperature():
    # Read the ADC value from the thermistor
    adc_value = thermistor.read_u16()
    # Calculate the voltage across the thermistor
    voltage = adc_value * (VCC / 65535)
    # Calculate the resistance of the thermistor
    R_thermistor = R_DIVIDER * (VCC / voltage - 1)
    # Calculate the temperature in Kelvin using the Beta parameter equation
    temperature_k = 1 / (1/T0 + math.log(R_thermistor/R0) / BETA)
    # Convert temperature to Celsius
    temperature_c = temperature_k - 273.15
    return temperature_c

def button_isr(pin):
    global last_interrupt_time
    current_time = time.ticks_ms()
    if time.ticks_diff(current_time, last_interrupt_time) > debounce_time:
        temperature = read_temperature()
        print("Temperature: {:.2f} °C".format(temperature))
        last_interrupt_time = current_time

# Setup button interrupt
button.irq(trigger=Pin.IRQ_FALLING, handler=button_isr)

# Timer callback for blinking LED
def blink_led(timer):
    led.toggle()

# Setup timer to blink LED every second
timer = Timer()
timer.init(period=1000, mode=Timer.PERIODIC, callback=blink_led)

# Main loop (empty, as we rely on interrupts and timer)
while True:
    pass