16x2 LCD Raspi-Server

#!/usr/bin/python
import smbus
import time
import psutil
import socket
import subprocess
import os
import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BOARD)
GPIO.setwarnings(False)

GPIO.setup(8, GPIO.IN)
GPIO.setup(10, GPIO.IN)
GPIO.setup(26, GPIO.OUT)
GPIO.setup(24, GPIO.OUT)
GPIO.setup(22, GPIO.OUT)

GPIO.output(26, 0)
GPIO.output(24, 0)
GPIO.output(22, 0)

########################################################

I2C_ADDR  = 0x27
LCD_WIDTH = 16

LCD_CHR = 1
LCD_CMD = 0

LCD_LINE_1 = 0x80
LCD_LINE_2 = 0xC0
LCD_LINE_3 = 0x94
LCD_LINE_4 = 0xD4

LCD_BACKLIGHT  = 0x08  # On
#LCD_BACKLIGHT = 0x00  # Off

ENABLE = 0b00000100

E_PULSE = 0.0005
E_DELAY = 0.0005

bus = smbus.SMBus(1)

def red():
  GPIO.output(26, 1)
  GPIO.output(24, 0)
  GPIO.output(22, 0)

def green():
  GPIO.output(26, 0)
  GPIO.output(24, 1)
  GPIO.output(22, 0)

def blue():
  GPIO.output(26, 0)
  GPIO.output(24, 0)
  GPIO.output(22, 1)

def black():
  GPIO.output(26, 0)
  GPIO.output(24, 0)
  GPIO.output(22, 0)

def lcd_init():
  lcd_byte(0x33,LCD_CMD)
  lcd_byte(0x32,LCD_CMD)
  lcd_byte(0x06,LCD_CMD)
  lcd_byte(0x0C,LCD_CMD)
  lcd_byte(0x28,LCD_CMD)
  lcd_byte(0x01,LCD_CMD)
  time.sleep(E_DELAY)

def lcd_byte(bits, mode):
  bits_high = mode | (bits & 0xF0) | LCD_BACKLIGHT
  bits_low = mode | ((bits<<4) & 0xF0) | LCD_BACKLIGHT

  bus.write_byte(I2C_ADDR, bits_high)
  lcd_toggle_enable(bits_high)

  bus.write_byte(I2C_ADDR, bits_low)
  lcd_toggle_enable(bits_low)

def lcd_toggle_enable(bits):
  time.sleep(E_DELAY)
  bus.write_byte(I2C_ADDR, (bits | ENABLE))
  time.sleep(E_PULSE)
  bus.write_byte(I2C_ADDR,(bits & ~ENABLE))
  time.sleep(E_DELAY)

def lcd_string(message,line):
  message = message.ljust(LCD_WIDTH," ")
  lcd_byte(line, LCD_CMD)
  for i in range(LCD_WIDTH):
    lcd_byte(ord(message[i]),LCD_CHR)

def getCpuTemperature():
  tempFile = open( "/sys/class/thermal/thermal_zone0/temp" )
  cpu_temp = tempFile.read()
  tempFile.close()
  return float(cpu_temp)/1000

def getRAMinfo():
    p = os.popen('free')
    i = 0
    while 1:
        i = i + 1
        line = p.readline()
        if i==2:
            return(line.split()[1:4])

########################################################

host = socket.gethostname()
ipnum = subprocess.check_output(["hostname", "-I"])

########################################################

def main():
  # Main program block
  blue()
  # Initialise display
  lcd_init()

  ## state - decides what LED should be on and off
  ## initialize to 0 or all off
  state = 1

  ## increment - the direction of states
  ## initialize to 1 or increasing
  inc = 1

  ## Set prev_input's initial value to 2
  prev_input=2

  while True:

    ## When state toggle button is pressed
    if ( GPIO.input(8) == True ):
        green()
        time.sleep(1)
        state = state + 1
    else:
        time.sleep(0.2)

    if (state == 1): #CPU
#            print("CPU")
            blue()
            CPU_usage = psutil.cpu_percent(interval = .5)
            lcd_string("CPU Load   %s%%" % (CPU_usage),LCD_LINE_1)
            lcd_string("CPU Temp   %s" % (getCpuTemperature()),LCD_LINE_2)

    elif (state == 2): #RAM
#            print("RAM")
            blue()
            RAM_stats = getRAMinfo()
            RAM_used = round(int(RAM_stats[1]) / 1000,1)
            RAM_free = round(int(RAM_stats[2]) / 1000,1)
            lcd_string("RAM Used %sMB   " % (RAM_used),LCD_LINE_1)
            lcd_string("RAM Free  %sMB   " % (RAM_free),LCD_LINE_2)

    elif (state == 3): #IP
#            print("IP")
            blue()
            lcd_string("%s" % (host),LCD_LINE_1)
            lcd_string("%s" % (ipnum)[0:14],LCD_LINE_2)
#            print(host)
#            print(ipnum)[0:14]

    elif (state == 4): #SHUTDOWN
            if ( state == 4 and GPIO.input(10) == True ):
#                print("SHUTDOWN BUTTON")
                red()
                time.sleep(2)
                os.system('sudo shutdown -h now')
                exit()
            else:
#                print("SHUTDOWN")
                blue()
                lcd_string("SHUTDOWN",LCD_LINE_1)
                lcd_string(" ",LCD_LINE_2)

    elif (state == 5): #REBOOT
            if ( state == 5 and GPIO.input(10) == True ):
#                print("REBOOT BUTTON")
                red()
                time.sleep(2)
                os.system('sudo shutdown -r now')
                exit()
            else:
#                print("REBOOT")
                blue()
                lcd_string("REBOOT",LCD_LINE_1)
                lcd_string(" ",LCD_LINE_2)

    elif (state == 6): #OFF
#            print("OFF")
            LCD_BACKLIGHT = 0x00
            black()
            state = state - 6

    else:
        time.sleep(0.2)

if __name__ == '__main__':
  try:
    main()
  except (KeyboardInterrupt, SystemExit):
    LCD_BACKLIGHT = 0x00
    black()
    pass
  finally:
    lcd_byte(0x01, LCD_CMD)