Python • Re: Button to restart Pi, button to restart program

Code:

#!/home/brewmaster/projects/autoferment/venv/bin/python3"""The purpose of this program is to take temperature readings from a DS18B20 temperaturesensor (function), write to a file in CSV format (for export to excel), and print what is going into thefile on an LCD screen"""import datetimefrom dataclasses import dataclassimport subprocessimport timefrom gpiozero import Button, OutputDevicefrom RPLCD.i2c import CharLCDfrom temperature import read_temperatureRELAY_PIN = 17MIN_TEMP = 24MAX_TEMP = 26STOP_BUTTON = 27@dataclassclass Heater:    """    https://en.wikipedia.org/wiki/Bang%E2%80%93bang_control    """    min_temp: float    max_temp: float    relay: OutputDevice    last: bool | None = None    def set_state(self, degree_celsius) -> tuple[bool, bool]:        """        If the heater is off, then the temperature must be lower than min_temp to switch the heater on        If the heater is on, then the temperature must be higher than max_temp to switch the heater off        """        # getting the first time the current state of the output        if self.last is None:            # if active_high is False, then the signal is inverted            self.last = bool(self.relay.value ^ self.relay.active_high)        _last = self.last        if self.last and degree_celsius > self.max_temp:            self.last = False        elif not self.last and degree_celsius < self.min_temp:            self.last = True        changed = _last != self.last        if changed:            if self.last:                # the method on and off does the right thing,                # even if active_high is False                self.relay.on()            else:                self.relay.off()        return changed, self.lastdef temp_display(heater: Heater, lcd: CharLCD):    celsius, fahrenheit = read_temperature()    if celsius is None:        return    with open("Ferment Log.txt", "a+") as fd:        fd.write(            f"{datetime.datetime.now():%m/%d/%Y,%H:%M:%S},Temperatures:{celsius},{fahrenheit}"        )        fd.write("\n")    lcd.clear()    lcd.write_string(f"Temp: {celsius:.2f}°C")    # the method heater.set_state also activates/deactivates the relay    state_changed, new_state = heater.set_state(celsius)    if state_changed:        if new_state:            print("Power on", celsius)        else:            print("Power off", celsius)def main(heater, lcd):    while True:        temp_display(heater, lcd)        time.sleep(1)def shutdown():    subprocess.run(["shutdown", "-h", "now"])stopButton = Button(STOP_BUTTON)stopButton.when_activated = shutdownrelay = OutputDevice(RELAY_PIN, active_high=False, initial_value=True)lcd = CharLCD(i2c_expander="PCF8574", address=0x27, port=1, cols=16, rows=2, dotsize=8)heater = Heater(min_temp=MIN_TEMP, max_temp=MAX_TEMP, relay=relay)try:    main(heater, lcd)except KeyboardInterrupt:    lcd.clear()    lcd.write_string("Cancelled by\n\rUser")

Code:

"""The purpose of this script is to take temperature readings from a DS18B20 temperaturesensor, then have the function return the temperature in F and Celcius"""import reimport subprocessfrom pathlib import PathDEVICE = "28-3ce1e3809a4e"MODULES = ("w1-gpio", "w1-therm")for module in MODULES:    subprocess.run(["modprobe", module])def read_temperature(device: str | None = None) -> tuple[float | None, float | None]:    """        24 01 4b 46 7f ff 0c 10 48 : crc=48 YES        24 01 4b 46 7f ff 0c 10 48 t=18250    18.25 °C    """    device = device or DEVICE    sensor_data = Path("/sys/bus/w1/devices/").joinpath(DEVICE, "w1_slave").read_text()    if not re.search(r"crc=\d+ YES", sensor_data):        return None, None    if match := re.search(r"t=(\d+)", sensor_data):        celsius = int(match.group(1)) / 1_000        fahrenheit = celsius * 9 / 5 + 32        return celsius, fahrenheit    return None, None