from machine import ADC, I2C, Pin, Timer
from pico_i2c_lcd import I2cLcd
from math import log
import utime

sda = Pin(0)
scl = Pin(1)

pin = Pin(2, Pin.OUT)  
pin1 = Pin(26, Pin.OUT) 
pin2 = Pin(21, Pin.OUT) 


i2c = I2C(0, sda=sda, scl=scl, freq=400000)
device = i2c.scan()
i2caddr = device[0]


BETA = 3950


lcd = I2cLcd(i2c, i2caddr, 2, 16)


timer = Timer(-1)


overheat_time = 0 


def fn(Timer):
    global overheat_time  
    
    lcd.clear()
    A0 = ADC(Pin(28))
    val = A0.read_u16()  
    
    temp = (1 / (log(1 / (65535 / val - 1)) / BETA + (1 / 298.15))) - 273.15
    
    if temp >= 10 and temp <= 33:
        pin1.value(0)  
        pin.value(1)   
        pin2.value(0)  
        overheat_time = 0  
    else:
        pin.value(0)
        if overheat_time < 5:   
            pin1.value(1)  
        
        if temp > 33:
            overheat_time += 1  
            if overheat_time > 5: 
                pin1.value(0) 
                pin2.toggle()  
                lcd.putstr("Danger!") 
                utime.sleep(2)
            else:
                pin2.value(0)  
        else:
            overheat_time = 0 

    lcd.clear()
    lcd.putstr(f"Temp: {temp:.2f} C")

timer.init(period=500, mode=Timer.PERIODIC, callback=fn)