import _thread
import time
from dht22_oled import DHT22_OLED
from servo_control import ServoControl  # Asegúrate de que esta clase esté correctamente definida

# Define los pines GPIO
SERVO_PIN = 4
BUTTON_PIN = 34
NEOPIXEL_PIN = 16
NUM_NEOPIXELS = 16
TRIGGER_PIN = 33
ECHO_PIN = 32
POTENTIOMETER_PIN = 35  # Define el pin del potenciómetro

DHT22_PIN = 18       # Pin GPIO al que está conectado el sensor DHT22
I2C_SDA_PIN = 21     # Pin SDA del I2C
I2C_SCL_PIN = 22     # Pin SCL del I2C
OLED_WIDTH = 128     # Ancho de la pantalla OLED
OLED_HEIGHT = 64     # Alto de la pantalla OLED
SERVO_PIN_OLED = 23  # Pin GPIO para el servo controlado por la temperatura

# Configuración para elegir qué clase ejecutar
RUN_SERVO_CONTROL = True  # Cambia a True para ejecutar ServoControl
RUN_DHT22_OLED = True     # Cambia a True para ejecutar DHT22_OLED

# Crear instancia de las clases
sensor_display = DHT22_OLED(DHT22_PIN, I2C_SDA_PIN, I2C_SCL_PIN, OLED_WIDTH, OLED_HEIGHT, SERVO_PIN_OLED)
servo_control = ServoControl(SERVO_PIN, BUTTON_PIN, NEOPIXEL_PIN, NUM_NEOPIXELS, TRIGGER_PIN, ECHO_PIN, POTENTIOMETER_PIN)

def run_dht22():
    if RUN_DHT22_OLED:
        sensor_display.run(interval=1)

def run_servo_control():
    if RUN_SERVO_CONTROL:
        servo_control.run()

# Ejecutar las funciones en hilos separados
if RUN_SERVO_CONTROL:
    _thread.start_new_thread(run_servo_control, ())

if RUN_DHT22_OLED:
    _thread.start_new_thread(run_dht22, ())

# Mantener el programa principal en ejecución
try:
    while True:
        time.sleep(1)  # Mantener el hilo principal activo
except KeyboardInterrupt:
    print("Programa terminado")


main.py

diagram.json

from machine import PWM
import math

# originally by Radomir Dopieralski http://sheep.art.pl
# from https://bitbucket.org/thesheep/micropython-servo

class Servo:
    """
    A simple class for controlling hobby servos.

    Args:
        pin (machine.Pin): The pin where servo is connected. Must support PWM.
        freq (int): The frequency of the signal, in hertz.
        min_us (int): The minimum signal length supported by the servo.
        max_us (int): The maximum signal length supported by the servo.
        angle (int): The angle between the minimum and maximum positions.

    """
    def __init__(self, pin, freq=50, min_us=600, max_us=2400, angle=180):
        self.min_us = min_us
        self.max_us = max_us
        self.us = 0
        self.freq = freq
        self.angle = angle
        self.pwm = PWM(pin, freq=freq, duty=0)

    def write_us(self, us):
        """Set the signal to be ``us`` microseconds long. Zero disables it."""
        if us == 0:
            self.pwm.duty(0)
            return
        us = min(self.max_us, max(self.min_us, us))
        duty = us * 1024 * self.freq // 1000000
        self.pwm.duty(duty)

    def write_angle(self, degrees=None, radians=None):
        """Move to the specified angle in ``degrees`` or ``radians``."""
        if degrees is None:
            degrees = math.degrees(radians)
        degrees = degrees % 360
        total_range = self.max_us - self.min_us
        us = self.min_us + total_range * degrees // self.angle
        self.write_us(us)

servo.py

from machine import Pin, time_pulse_us
from utime import sleep_us

__version__ = '0.2.1'
__author__ = 'Roberto Sánchez'
__license__ = "Apache License 2.0. https://www.apache.org/licenses/LICENSE-2.0"

class HCSR04:
    """
    Driver to use the untrasonic sensor HC-SR04.
    The sensor range is between 2cm and 4m.

    The timeouts received listening to echo pin are converted to OSError('Out of range')

    """
    # echo_timeout_us is based in chip range limit (400cm)
    def __init__(self, trigger_pin, echo_pin, echo_timeout_us=500*2*30):
        """
        trigger_pin: Output pin to send pulses
        echo_pin: Readonly pin to measure the distance. The pin should be protected with 1k resistor
        echo_timeout_us: Timeout in microseconds to listen to echo pin. 
        By default is based in sensor limit range (4m)
        """
        self.echo_timeout_us = echo_timeout_us
        # Init trigger pin (out)
        self.trigger = Pin(trigger_pin, mode=Pin.OUT, pull=None)
        self.trigger.value(0)

        # Init echo pin (in)
        self.echo = Pin(echo_pin, mode=Pin.IN, pull=None)

    def _send_pulse_and_wait(self):
        """
        Send the pulse to trigger and listen on echo pin.
        We use the method `machine.time_pulse_us()` to get the microseconds until the echo is received.
        """
        self.trigger.value(0) # Stabilize the sensor
        sleep_us(5)
        self.trigger.value(1)
        # Send a 10us pulse.
        sleep_us(10)
        self.trigger.value(0)
        try:
            pulse_time = time_pulse_us(self.echo, 1, self.echo_timeout_us)
            # time_pulse_us returns -2 if there was timeout waiting for condition; and -1 if there was timeout during the main measurement. It DOES NOT raise an exception
            # ...as of MicroPython 1.17: http://docs.micropython.org/en/v1.17/library/machine.html#machine.time_pulse_us
            if pulse_time < 0:
                MAX_RANGE_IN_CM = const(500) # it's really ~400 but I've read people say they see it working up to ~460
                pulse_time = int(MAX_RANGE_IN_CM * 29.1) # 1cm each 29.1us
            return pulse_time
        except OSError as ex:
            if ex.args[0] == 110: # 110 = ETIMEDOUT
                raise OSError('Out of range')
            raise ex

    def distance_mm(self):
        """
        Get the distance in milimeters without floating point operations.
        """
        pulse_time = self._send_pulse_and_wait()

        # To calculate the distance we get the pulse_time and divide it by 2 
        # (the pulse walk the distance twice) and by 29.1 becasue
        # the sound speed on air (343.2 m/s), that It's equivalent to
        # 0.34320 mm/us that is 1mm each 2.91us
        # pulse_time // 2 // 2.91 -> pulse_time // 5.82 -> pulse_time * 100 // 582 
        mm = pulse_time * 100 // 582
        return mm

    def distance_cm(self):
        """
        Get the distance in centimeters with floating point operations.
        It returns a float
        """
        pulse_time = self._send_pulse_and_wait()

        # To calculate the distance we get the pulse_time and divide it by 2 
        # (the pulse walk the distance twice) and by 29.1 becasue
        # the sound speed on air (343.2 m/s), that It's equivalent to
        # 0.034320 cm/us that is 1cm each 29.1us
        cms = (pulse_time / 2) / 29.1
        return cms

hcsr04.py

from machine import Pin, ADC, Timer
import neopixel
import time
from servo import Servo
from hcsr04 import HCSR04

class ServoControl:
    def __init__(self, servo_pin, button_pin, neopixel_pin, num_neopixels, trigger_pin, echo_pin, potentiometer_pin):
        self.servo = Servo(Pin(servo_pin))
        self.button = Pin(button_pin, Pin.IN, Pin.PULL_UP)
        self.neopixels = neopixel.NeoPixel(Pin(neopixel_pin), num_neopixels)
        self.sensor = HCSR04(trigger_pin=trigger_pin, echo_pin=echo_pin)
        self.potentiometer = ADC(Pin(potentiometer_pin))  # Potenciómetro

        self.position = 0  # 0 para cerrado, 90 para abierto
        self.last_button_state = True  # El botón no está presionado inicialmente
        self.button_pressed = False  # Bandera para rastrear si se presionó el botón
        self.sensor_active = True  # Bandera para rastrear si el sensor debe estar activo
        
        # Inicializa el servo en la posición cerrada
        self.set_servo_angle(self.position)
        self.update_neopixels()
        
        # Timer para verificar la distancia periódicamente
        self.timer = Timer(0)
        self.timer.init(period=500, mode=Timer.PERIODIC, callback=self.check_distance)

    def set_servo_angle(self, angle):
        self.servo.write_angle(degrees=angle)

    def update_neopixels(self):
        brightness = self.read_potentiometer()  # Obtiene el valor del potenciómetro
        if self.position == 0:
            color = (255, 0, 0)  # Rojo
        else:
            color = (0, 255, 0)  # Verde
        
        # Ajusta el brillo
        r = int(color[0] * brightness / 255)
        g = int(color[1] * brightness / 255)
        b = int(color[2] * brightness / 255)
        
        for i in range(len(self.neopixels)):
            self.neopixels[i] = (r, g, b)
        self.neopixels.write()

    def read_potentiometer(self):
        # Lee el valor del ADC y lo convierte al rango de 0-255
        adc_value = self.potentiometer.read()
        return int(adc_value * 255 / 4095)  # Ajustado para el rango del ADC del ESP32

    def check_button(self):
        current_button_state = self.button.value()
        
        # Verifica si el botón ha sido presionado (transición de alto a bajo)
        if not current_button_state and self.last_button_state:
            time.sleep_ms(200)  # Retraso por rebote
            if not self.button.value():  # El botón sigue presionado
                self.button_pressed = not self.button_pressed  # Alterna el estado del botón
                if self.button_pressed:
                    self.activate_button_mode()
                else:
                    self.activate_sensor_mode()

        self.last_button_state = current_button_state

    def activate_button_mode(self):
        self.sensor_active = False
        self.toggle_servo()
        
    def activate_sensor_mode(self):
        self.sensor_active = True

    def toggle_servo(self):
        if self.position == 0:
            self.position = 90  # Posición abierta
        else:
            self.position = 0  # Posición cerrada
        self.set_servo_angle(self.position)
        self.update_neopixels()

    def check_distance(self, t):
        if self.sensor_active:
            distance = self.sensor.distance_cm()
            if distance < 101:
                if self.position != 0:
                    self.position = 0
                    self.set_servo_angle(self.position)
                    self.update_neopixels()
            elif 101 <= distance <= 400:
                if self.position != 90:
                    self.position = 90
                    self.set_servo_angle(self.position)
                    self.update_neopixels()

    def run(self):
        # Asegúrate de que el servo esté en la posición cerrada al inicio
        self.position = 0  # Establece la posición cerrada
        self.set_servo_angle(self.position)
        time.sleep_ms(1000)  # Añade un pequeño retraso para asegurar la estabilidad del servo
        
        while True:
            self.check_button()
            self.update_neopixels()  # Actualiza los Neopixels según el valor del potenciómetro
            time.sleep_ms(50)


servo_control.py

from machine import Pin, I2C, PWM
import dht
import ssd1306
import time

class DHT22_OLED:
    def __init__(self, dht_pin, i2c_sda, i2c_scl, oled_width, oled_height, servo_pin):
        # Inicializar el sensor DHT22
        self.dht_sensor = dht.DHT22(Pin(dht_pin))
        
        # Configurar el I2C para la pantalla OLED
        self.i2c = I2C(0, scl=Pin(i2c_scl), sda=Pin(i2c_sda))
        self.oled = ssd1306.SSD1306_I2C(oled_width, oled_height, self.i2c)
        
        # Configurar el servo motor
        self.servo = PWM(Pin(servo_pin), freq=50)
        self.servo.duty(0)  # Inicialmente apagar el servo
        
        # Inicializar las variables de temperatura y humedad
        self.last_temp = None
        self.last_humidity = None

    def read_and_display(self):
        # Leer datos del sensor DHT22
        self.dht_sensor.measure()
        temperature = self.dht_sensor.temperature()
        humidity = self.dht_sensor.humidity()
        
        # Verificar si ha habido cambios en la temperatura o humedad
        if (self.last_temp is None or abs(temperature - self.last_temp) > 0.1 or
            self.last_humidity is None or abs(humidity - self.last_humidity) > 0.1):
            # Limpiar la pantalla
            self.oled.fill(0)
            
            # Mostrar temperatura y humedad
            self.oled.text('Temp: {:.1f}C'.format(temperature), 0, 0)
            self.oled.text('Hum: {:.1f}%'.format(humidity), 0, 10)
            
            # Actualizar la pantalla
            self.oled.show()
            
            # Actualizar las últimas lecturas
            self.last_temp = temperature
            self.last_humidity = humidity

        # Controlar el servo motor en función de la temperatura
        self.control_servo(temperature)

    def control_servo(self, temperature):
        if temperature >= 27:
            self.barrido_servo()
        else:
            self.servo.duty(0)  # Detener el servo

    def barrido_servo(self):
        for angle in range(0, 181, 1):  # Barrido de 0º a 180º
            self.servo.duty(self.map_angle_to_duty(angle))
            time.sleep(0.01)  # Ajusta la velocidad del barrido aquí
        for angle in range(180, -1, -1):  # Barrido de 180º a 0º
            self.servo.duty(self.map_angle_to_duty(angle))
            time.sleep(0.01)  # Ajusta la velocidad del barrido aquí

    def map_angle_to_duty(self, angle):
        # Mapea el ángulo (0º-180º) a un valor de duty (0-1023)
        return int(27 + (angle / 180) * 80)  # Ajusta según el servo

    def run(self, interval=1):
        while True:
            self.read_and_display()  # Actualizar la pantalla OLED y el servo motor
            time.sleep(interval)


dht22_oled.py

# MicroPython SSD1306 OLED driver, I2C and SPI interfaces

from micropython import const
import framebuf


# register definitions
SET_CONTRAST = const(0x81)
SET_ENTIRE_ON = const(0xA4)
SET_NORM_INV = const(0xA6)
SET_DISP = const(0xAE)
SET_MEM_ADDR = const(0x20)
SET_COL_ADDR = const(0x21)
SET_PAGE_ADDR = const(0x22)
SET_DISP_START_LINE = const(0x40)
SET_SEG_REMAP = const(0xA0)
SET_MUX_RATIO = const(0xA8)
SET_COM_OUT_DIR = const(0xC0)
SET_DISP_OFFSET = const(0xD3)
SET_COM_PIN_CFG = const(0xDA)
SET_DISP_CLK_DIV = const(0xD5)
SET_PRECHARGE = const(0xD9)
SET_VCOM_DESEL = const(0xDB)
SET_CHARGE_PUMP = const(0x8D)

# Subclassing FrameBuffer provides support for graphics primitives
# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
class SSD1306(framebuf.FrameBuffer):
    def __init__(self, width, height, external_vcc):
        self.width = width
        self.height = height
        self.external_vcc = external_vcc
        self.pages = self.height // 8
        self.buffer = bytearray(self.pages * self.width)
        super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
        self.init_display()

    def init_display(self):
        for cmd in (
            SET_DISP | 0x00,  # off
            # address setting
            SET_MEM_ADDR,
            0x00,  # horizontal
            # resolution and layout
            SET_DISP_START_LINE | 0x00,
            SET_SEG_REMAP | 0x01,  # column addr 127 mapped to SEG0
            SET_MUX_RATIO,
            self.height - 1,
            SET_COM_OUT_DIR | 0x08,  # scan from COM[N] to COM0
            SET_DISP_OFFSET,
            0x00,
            SET_COM_PIN_CFG,
            0x02 if self.width > 2 * self.height else 0x12,
            # timing and driving scheme
            SET_DISP_CLK_DIV,
            0x80,
            SET_PRECHARGE,
            0x22 if self.external_vcc else 0xF1,
            SET_VCOM_DESEL,
            0x30,  # 0.83*Vcc
            # display
            SET_CONTRAST,
            0xFF,  # maximum
            SET_ENTIRE_ON,  # output follows RAM contents
            SET_NORM_INV,  # not inverted
            # charge pump
            SET_CHARGE_PUMP,
            0x10 if self.external_vcc else 0x14,
            SET_DISP | 0x01,
        ):  # on
            self.write_cmd(cmd)
        self.fill(0)
        self.show()

    def poweroff(self):
        self.write_cmd(SET_DISP | 0x00)

    def poweron(self):
        self.write_cmd(SET_DISP | 0x01)

    def contrast(self, contrast):
        self.write_cmd(SET_CONTRAST)
        self.write_cmd(contrast)

    def invert(self, invert):
        self.write_cmd(SET_NORM_INV | (invert & 1))

    def show(self):
        x0 = 0
        x1 = self.width - 1
        if self.width == 64:
            # displays with width of 64 pixels are shifted by 32
            x0 += 32
            x1 += 32
        self.write_cmd(SET_COL_ADDR)
        self.write_cmd(x0)
        self.write_cmd(x1)
        self.write_cmd(SET_PAGE_ADDR)
        self.write_cmd(0)
        self.write_cmd(self.pages - 1)
        self.write_data(self.buffer)


class SSD1306_I2C(SSD1306):
    def __init__(self, width, height, i2c, addr=0x3C, external_vcc=False):
        self.i2c = i2c
        self.addr = addr
        self.temp = bytearray(2)
        self.write_list = [b"\x40", None]  # Co=0, D/C#=1
        super().__init__(width, height, external_vcc)

    def write_cmd(self, cmd):
        self.temp[0] = 0x80  # Co=1, D/C#=0
        self.temp[1] = cmd
        self.i2c.writeto(self.addr, self.temp)

    def write_data(self, buf):
        self.write_list[1] = buf
        self.i2c.writevto(self.addr, self.write_list)


class SSD1306_SPI(SSD1306):
    def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
        self.rate = 10 * 1024 * 1024
        dc.init(dc.OUT, value=0)
        res.init(res.OUT, value=0)
        cs.init(cs.OUT, value=1)
        self.spi = spi
        self.dc = dc
        self.res = res
        self.cs = cs
        import time

        self.res(1)
        time.sleep_ms(1)
        self.res(0)
        time.sleep_ms(10)
        self.res(1)
        super().__init__(width, height, external_vcc)

    def write_cmd(self, cmd):
        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
        self.cs(1)
        self.dc(0)
        self.cs(0)
        self.spi.write(bytearray([cmd]))
        self.cs(1)

    def write_data(self, buf):
        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
        self.cs(1)
        self.dc(1)
        self.cs(0)
        self.spi.write(buf)
        self.cs(1)


ssd1306.py

"""Implements a HD44780 character LCD connected via PCF8574 on I2C. 
   This was tested with: https://www.wemos.cc/product/d1-mini.html""" 
from lcd_api import LcdApi 
from machine import I2C 
from time import sleep_ms 
# The PCF8574 has a jumper selectable address: 0x20 - 0x27 
#DEFAULT_I2C_ADDR = 0x20 
# Defines shifts or masks for the various LCD line attached to the PCF8574 
MASK_RS = 0x01 
MASK_RW = 0x02 
MASK_E = 0x04 
SHIFT_BACKLIGHT = 3 
SHIFT_DATA = 4 
class I2cLcd(LcdApi): 
    """Implements a HD44780 character LCD connected via PCF8574 on I2C.""" 
    def __init__(self, i2c, i2c_addr, num_lines, num_columns): 
        self.i2c = i2c 
        self.i2c_addr = i2c_addr 
        self.i2c.writeto(self.i2c_addr, bytearray([0])) 
        sleep_ms(20)   # Allow LCD time to powerup 
        # Send reset 3 times 
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET) 
        sleep_ms(5)    # need to delay at least 4.1 msec 
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET) 
        sleep_ms(1) 
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET) 
        sleep_ms(1) 
        # Put LCD into 4 bit mode 
        self.hal_write_init_nibble(self.LCD_FUNCTION) 
        sleep_ms(1) 
        LcdApi.__init__(self, num_lines, num_columns) 
        cmd = self.LCD_FUNCTION 
        if num_lines > 1: 
            cmd |= self.LCD_FUNCTION_2LINES 
        self.hal_write_command(cmd) 
    def hal_write_init_nibble(self, nibble): 
        """Writes an initialization nibble to the LCD. 
        This particular function is only used during initialization. 
        """ 
        byte = ((nibble >> 4) & 0x0f) << SHIFT_DATA 
        self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E])) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte])) 
    def hal_backlight_on(self): 
        """Allows the hal layer to turn the backlight on.""" 
        self.i2c.writeto(self.i2c_addr, bytearray([1 << SHIFT_BACKLIGHT])) 
    def hal_backlight_off(self): 
        """Allows the hal layer to turn the backlight off.""" 
        self.i2c.writeto(self.i2c_addr, bytearray([0])) 
    def hal_write_command(self, cmd): 
        """Writes a command to the LCD. 
        Data is latched on the falling edge of E. 
        """ 
        byte = ((self.backlight << SHIFT_BACKLIGHT) | (((cmd >> 4) & 0x0f) << SHIFT_DATA)) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E])) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte])) 
        byte = ((self.backlight << SHIFT_BACKLIGHT) | ((cmd & 0x0f) << SHIFT_DATA)) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E])) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte])) 
        if cmd <= 3: 
            # The home and clear commands require a worst case delay of 4.1 msec 
            sleep_ms(5) 
    def hal_write_data(self, data): 
        """Write data to the LCD.""" 
        byte = (MASK_RS | (self.backlight << SHIFT_BACKLIGHT) | (((data >> 4) & 0x0f) << SHIFT_DATA)) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E])) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte])) 
        byte = (MASK_RS | (self.backlight << SHIFT_BACKLIGHT) | ((data & 0x0f) << SHIFT_DATA)) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E])) 
        self.i2c.writeto(self.i2c_addr, bytearray([byte]))

i2c_lcd.py

"""Provides an API for talking to HD44780 compatible character LCDs.""" 
import time 
class LcdApi: 
    """Implements the API for talking with HD44780 compatible character LCDs. 
    This class only knows what commands to send to the LCD, and not how to get 
    them to the LCD. 
    It is expected that a derived class will implement the hal_xxx functions. 
    """ 
    # The following constant names were lifted from the avrlib lcd.h 
    # header file, however, I changed the definitions from bit numbers 
    # to bit masks. 
    # 
    # HD44780 LCD controller command set 
    LCD_CLR = 0x01              # DB0: clear display 
    LCD_HOME = 0x02             # DB1: return to home position 
    LCD_ENTRY_MODE = 0x04       # DB2: set entry mode 
    LCD_ENTRY_INC = 0x02        # --DB1: increment 
    LCD_ENTRY_SHIFT = 0x01      # --DB0: shift 
    LCD_ON_CTRL = 0x08          # DB3: turn lcd/cursor on 
    LCD_ON_DISPLAY = 0x04       # --DB2: turn display on 
    LCD_ON_CURSOR = 0x02        # --DB1: turn cursor on 
    LCD_ON_BLINK = 0x01         # --DB0: blinking cursor 
    LCD_MOVE = 0x10             # DB4: move cursor/display 
    LCD_MOVE_DISP = 0x08        # --DB3: move display (0-> move cursor) 
    LCD_MOVE_RIGHT = 0x04       # --DB2: move right (0-> left) 
    LCD_FUNCTION = 0x20         # DB5: function set 
    LCD_FUNCTION_8BIT = 0x10    # --DB4: set 8BIT mode (0->4BIT mode) 
    LCD_FUNCTION_2LINES = 0x08  # --DB3: two lines (0->one line) 
    LCD_FUNCTION_10DOTS = 0x04  # --DB2: 5x10 font (0->5x7 font) 
    LCD_FUNCTION_RESET = 0x30   # See "Initializing by Instruction" section 
    LCD_CGRAM = 0x40            # DB6: set CG RAM address 
    LCD_DDRAM = 0x80            # DB7: set DD RAM address 
    LCD_RS_CMD = 0 
    LCD_RS_DATA = 1 
    LCD_RW_WRITE = 0 
    LCD_RW_READ = 1 
    def __init__(self, num_lines, num_columns): 
        self.num_lines = num_lines 
        if self.num_lines > 4: 
            self.num_lines = 4 
        self.num_columns = num_columns 
        if self.num_columns > 40: 
            self.num_columns = 40 
        self.cursor_x = 0 
        self.cursor_y = 0 
        self.implied_newline = False 
        self.backlight = True 
        self.display_off() 
        self.backlight_on() 
        self.clear() 
        self.hal_write_command(self.LCD_ENTRY_MODE | self.LCD_ENTRY_INC) 
        self.hide_cursor() 
        self.display_on() 
    def clear(self): 
        """Clears the LCD display and moves the cursor to the top left 
        corner. 
        """ 
        self.hal_write_command(self.LCD_CLR) 
        self.hal_write_command(self.LCD_HOME) 
        self.cursor_x = 0 
        self.cursor_y = 0 
    def show_cursor(self): 
        """Causes the cursor to be made visible.""" 
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY | 
                               self.LCD_ON_CURSOR) 
    def hide_cursor(self): 
        """Causes the cursor to be hidden.""" 
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY) 
    def blink_cursor_on(self): 
        """Turns on the cursor, and makes it blink.""" 
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY | 
                               self.LCD_ON_CURSOR | self.LCD_ON_BLINK) 
    def blink_cursor_off(self): 
        """Turns on the cursor, and makes it no blink (i.e. be solid).""" 
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY | 
                               self.LCD_ON_CURSOR) 
    def display_on(self): 
        """Turns on (i.e. unblanks) the LCD.""" 
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY) 
    def display_off(self): 
        """Turns off (i.e. blanks) the LCD.""" 
        self.hal_write_command(self.LCD_ON_CTRL) 
    def backlight_on(self): 
        """Turns the backlight on. 
        This isn't really an LCD command, but some modules have backlight 
        controls, so this allows the hal to pass through the command. 
        """ 
        self.backlight = True 
        self.hal_backlight_on() 
    def backlight_off(self): 
        """Turns the backlight off. 
        This isn't really an LCD command, but some modules have backlight 
        controls, so this allows the hal to pass through the command. 
        """ 
        self.backlight = False 
        self.hal_backlight_off() 
    def move_to(self, cursor_x, cursor_y): 
        """Moves the cursor position to the indicated position. The cursor 
        position is zero based (i.e. cursor_x == 0 indicates first column). 
        """ 
        self.cursor_x = cursor_x 
        self.cursor_y = cursor_y 
        addr = cursor_x & 0x3f 
        if cursor_y & 1: 
            addr += 0x40    # Lines 1 & 3 add 0x40 
        if cursor_y & 2:    # Lines 2 & 3 add number of columns 
            addr += self.num_columns 
        self.hal_write_command(self.LCD_DDRAM | addr) 
    def putchar(self, char): 
        """Writes the indicated character to the LCD at the current cursor 
        position, and advances the cursor by one position. 
        """ 
        if char == '\n': 
            if self.implied_newline: 
                # self.implied_newline means we advanced due to a wraparound, 
                # so if we get a newline right after that we ignore it. 
                pass 
            else: 
                self.cursor_x = self.num_columns 
        else: 
            self.hal_write_data(ord(char)) 
            self.cursor_x += 1 
        if self.cursor_x >= self.num_columns: 
            self.cursor_x = 0 
            self.cursor_y += 1 
            self.implied_newline = (char != '\n') 
        if self.cursor_y >= self.num_lines: 
            self.cursor_y = 0 
        self.move_to(self.cursor_x, self.cursor_y) 
    def putstr(self, string): 
        """Write the indicated string to the LCD at the current cursor 
        position and advances the cursor position appropriately. 
        """ 
        for char in string: 
            self.putchar(char) 
    def custom_char(self, location, charmap): 
        """Write a character to one of the 8 CGRAM locations, available 
        as chr(0) through chr(7). 
        """ 
        location &= 0x7 
        self.hal_write_command(self.LCD_CGRAM | (location << 3)) 
        self.hal_sleep_us(40) 
        for i in range(8): 
            self.hal_write_data(charmap[i]) 
            self.hal_sleep_us(40) 
        self.move_to(self.cursor_x, self.cursor_y)
        
    def hal_backlight_on(self): 
        """Allows the hal layer to turn the backlight on. 
        If desired, a derived HAL class will implement this function. 
        """ 
        pass 
    def hal_backlight_off(self): 
        """Allows the hal layer to turn the backlight off. 
        If desired, a derived HAL class will implement this function. 
        """ 
        pass 
    def hal_write_command(self, cmd): 
        """Write a command to the LCD. 
        It is expected that a derived HAL class will implement this 
        function. 
        """ 
        raise NotImplementedError 
    def hal_write_data(self, data): 
        """Write data to the LCD. 
        It is expected that a derived HAL class will implement this 
        function. 
        """ 
        raise NotImplementedError 
    def hal_sleep_us(self, usecs): 
        """Sleep for some time (given in microseconds).""" 
        time.sleep_us(usecs)