rpi_display_lcd.py

import serial
import re
import Adafruit_CharLCD as LCD

# LCD STUFF
lcd_rs        = 25 
lcd_en        = 24
lcd_d4        = 23
lcd_d5        = 17
lcd_d6        = 18
lcd_d7        = 22
lcd_backlight = 4
lcd_columns = 16
lcd_rows = 2

lcd = LCD.Adafruit_CharLCD(lcd_rs, lcd_en, lcd_d4, lcd_d5, lcd_d6, lcd_d7, lcd_columns, lcd_rows, lcd_backlight)

# communication stuff
ser = serial.Serial(
    port="/dev/ttyUSB0",
    baudrate=9600,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.EIGHTBITS,
    timeout=1
)

display_regex = r"d:\w+"

while True:
    current_message = ser.read()
    # if we get the ready message from the udoo
    # we know the connection is established, so then just print it to the display
    if current_message == "udooready":
        lcd.clear()
        lcd.message("udoo ready")
        lcd.set_cursor(0, 1)
        lcd.message("pi ready")
    # if a message starts with d: , send this message to the lcd
    elif re.match(display_regex, current_message):
        lcd.clear()
        lcd.message(current_message[2:])