Script to control LG TVs via their serial interface. Not all LG TVs have this port, but if it does then you can control it directly from the computer without a remote. This script can also be used directly from a XBMC/Kodi keymap file with some indicated modifications.

LG_keyboard.py

#!/usr/bin/python
# Put this file in /usr/local/bin/ then chmod +x

import sys

# You need to tell python where to look for serial module if running from a keymap.
#sys.path.append("/usr/lib/python2.7/")

#set by computer, change to your needs
SERIAL_DEV = "/dev/ttyUSB0"
LOCKFILE = "/var/lock/LG_on_"+SERIAL_DEV.split("/")[-1]
#set by TV, read the manual for your TV's codes
LG_SET_NUM = "01"
INPUT = "xb"
HTPC = "a0"
WII = "40"
OSD = "kl"
REMOTE_BLOCK = "km"
POWER = "ka"
OFF = "00"
ON = "01"
QUERY = "FF"

import fcntl
import serial
import time
from optparse import OptionParser

parser = OptionParser(description="Sends commands to LG TV via serial connection")
parser.add_option("--power",
                  help="turn power off or on (opposite of current setting)",
                  action="store_true",
                  default=False)
parser.add_option("--power-on",
                  help="turn power on",
                  action="store_true",
                  default=False)
parser.add_option("--power-off",
                  help="turn power off",
                  action="store_true",
                  default=False)
parser.add_option("--htpc",
                  help="change to HTPC display",
                  action="store_const",
                  const=HTPC,
                  dest="input")
parser.add_option("--wii",
                  help="change to Wii Display",
                  action="store_const",
                  const=WII,
                  dest="input")
options, args = parser.parse_args()

#make sure only one instance runs at a time to save confusing everyone
lf = open(LOCKFILE, "w")
try:
    fcntl.lockf(lf, fcntl.LOCK_EX | fcntl.LOCK_NB)
except IOError:
    sys.exit(0)

#run a command
def LG(command, data):
    ser.write("%s %s %s\r" % (command, LG_SET_NUM, data))

#run a command and return its condition, always
def LG_return(command, data):
    status = ""
    while status == "":
        LG(command, data)
        timeout = 5
        while timeout > 0:
            timeout -= 1
            if ser.inWaiting() > 0:
                #if there are more than one return, they are separated by an x
                LG_returns = ser.read(ser.inWaiting()).split("x")
                for r in LG_returns:
                    if r == "":
                        continue
                    #need to match to the command we sent
                    elif r.split()[0] == command[1]:
                        #check if the command was processed correctly
                        if r.split()[2][:2] == "OK":
                            status = r.split()[2][2:]
                        #break out to either re-run command or return
                        timeout = 0
                        break
            time.sleep(0.2)
    return status

#the magic of python
ser = serial.Serial(SERIAL_DEV, timeout=0)
if options.power:
    state = LG_return(POWER, QUERY)
    if state == ON:
        LG_return(POWER, OFF)
    elif state == OFF:
        LG_return(POWER, ON)
elif options.power_on:
    LG_return(POWER, ON)
elif options.power_off:
    LG_return(POWER, OFF)
elif options.input:
    LG(INPUT, options.input)
else:
    parser.print_help()


#clean up
ser.read(ser.inWaiting())
ser.close()