LG Air Conditioner Infrared Control Python Script with pigpio

lgairctrl.py

#!/usr/bin/env python

# lgairctrl.py
# 2024-03-01
# Public Domain

"""
A utility to send an infrared command to certain, unknown models of LG Air Conditioners equipped with infrared. This utility currently supports the United States model LW1022IVSM with Fahrenheit temperature control (and probably many others). This script is meant to be run on a Raspberry Pi with pigpiod installed and an infrared LED module, or a bare IR LED with NPN transistor base connected to one of the GPIO pins.

To send a command use the following format. All options are required.

./lgairctrl.py -g <gpionumber> -m <mode> -t <temp> -f <fanspeed>

where mode is one of

o -- off
m -- max cool
e -- energy saver
s -- sleep mode (only works when unit is on. Send 'm' first, then 's' to enable sleep mode)
c -- clear sleep mode (puts unit back in previous mode, ie 'm')
f -- fan only
d -- dry (dehumidify)

temp is a number between and including 60 and 86 (fahrenheit)

and fanspeed is one of

1 -- low
2 -- med
3 -- high
"""

import time
import json
import os
import argparse

import pigpio # http://abyz.co.uk/rpi/pigpio/python.html

p = argparse.ArgumentParser()


p.add_argument("-g", "--gpio",   help="GPIO for TX", required=True, type=int)
p.add_argument("-m", "--mode",   help="o/off, m/max, e/enrgy svr, s/sleep, c/clr sleep, f/fan, d/dry", required=True)
p.add_argument("-t", "--temp",   help="60-86 in f", required=True)
p.add_argument("-f", "--fan",    help="1/lo 2/md 3/hi", required=True)
p.add_argument("-v", "--verbose", help="Be verbose",     action="store_true")


args = p.parse_args()

GPIO       = args.gpio
MODE       = args.mode
TEMP       = args.temp
FAN        = args.fan
VERBOSE    = args.verbose
FREQ       = 38.0
GAP_MS     = 100
GAP_S      = GAP_MS  / 1000.0


def printCmd(cmd):
    outstring = """FXD  FXD  SPCL MODE TEMP FANS CKSM\n"""
    for i, v in enumerate(cmd):
        outstring += str(v)
        if (i+1)%4 == 0:
            outstring += " "
    print(outstring)

def getChecksum(cmd): #LG checksum is the sum of each 4 bit group, discarding binary overflow (ie last 4 least significant bits)
    totalSum = 0
    for i in range(0, len(cmd), 4):
        sum4 = cmd[i]*8 + cmd[i+1]*4 + cmd[i+2]*2 + cmd[i+3]*1
        totalSum += sum4
    cksumArr = [int(x) for x in bin(totalSum%16)[2:]] #Get array of least 4 significant bits by modding by 16
    for i in range (0, 4-len(cksumArr)): #Pad array out to 4 digits with leading zeroes
        cksumArr = [0] + cksumArr
    if VERBOSE:
        print('checksum array: ' + str(cksumArr))
    return cksumArr

def carrier(gpio, frequency, micros):
    """
    Generate carrier square wave.
    """
    wf = []
    cycle = 1000.0 / frequency
    cycles = int(round(micros/cycle))
    on = int(round(cycle / 2.0))
    sofar = 0
    for c in range(cycles):
        target = int(round((c+1)*cycle))
        sofar += on
        off = target - sofar
        sofar += off
        wf.append(pigpio.pulse(1<<gpio, 0, on))
        wf.append(pigpio.pulse(0, 1<<gpio, off))
    return wf


def xmitcmd(cmd):
    pi = pigpio.pi() # Connect to Pi.
    pi.wave_clear() #Clear any previous stored waveforms
    
    if not pi.connected:
        print('Fatal error, could not connect to pigpiod!')
        exit(0)
        
    pi.set_mode(GPIO, pigpio.OUTPUT) # IR TX connected to this GPIO.

    pi.wave_add_new()

    emit_time = time.time()

    if VERBOSE:
        print("Playing")

    # Create wave, twice as many as the cmd plus 2 preamble bits and 1 ending bit

    wave = [0]*((len(cmd)*2)+3) #Add two bits for the preamble and one for ending bit
    
    #First add the preamble mark/space 
    wf = carrier(GPIO, FREQ, 3122) #Preamble mark is 3122
    pi.wave_add_generic(wf)
    #print('add mark 3122')
    wave[0] = pi.wave_create()
    pi.wave_add_generic([pigpio.pulse(0, 0, 9661)]) #Preamble space is 9661
    #print('add space 9661')
    wave[1] = pi.wave_create()
    
    pi.wave_add_generic([pigpio.pulse(0, 0, 507)]) #Short space is a pulse of 507
    SPACE_SHORT = pi.wave_create()
    pi.wave_add_generic([pigpio.pulse(0, 0, 1542)]) #Long space is a pulse of 1542
    SPACE_LONG = pi.wave_create()
    wf = carrier(GPIO, FREQ, 509) #Mark is a pulse of 509
    pi.wave_add_generic(wf)
    MARK = pi.wave_create()
    

    for i in range(0, len(cmd)):
        wave_index = i*2 + 2
        wave[wave_index] = MARK
        if(cmd[i] == 0):
            wave[wave_index+1] = SPACE_SHORT
        else:
            wave[wave_index+1] = SPACE_LONG
            
    #Add ending MARK bit
    wave[len(wave)-1] = MARK

    delay = emit_time - time.time()

    if delay > 0.0:
        time.sleep(delay)

    pi.wave_chain(wave) #This actually sends the entire command

    while pi.wave_tx_busy():
        time.sleep(0.002)

    emit_time = time.time() + GAP_S

    pi.stop() # Disconnect from Pi.
    

code_parts = {
    'FXD1': [1,0,0,0], #This part never changes for LG
    'FXD2': [1,0,0,0], #This part never changes for LG
    'SPCL': [1,1,0,0], #This is the default for the off command
    'MODE': [0,0,0,0], #This is the default for the off command
    'TEMP': [0,0,0,0], #This is the default for the off command
    'FANS': [0,1,0,1]  #This is the default for the off command
}

if(args.mode == 'o'):
    #This is the off cmd, which is already preconfigured in code_parts. Send it as is.
    print('Sending command: off')
else:
    resText = 'Sending command: '
    code_parts['SPCL'] = [0,0,0,0]
            
    tempMap = { #digits 1-4 are the values in the TEMP array, the 5th digit goes in position 2/idx1 in SPCL as a kicker
        '60': [0,0,0,1,0],
        '61': [0,0,0,1,1],
        '62': [0,0,1,0,0],
        '63': [0,0,1,0,1],
        '64': [0,0,1,1,0],
        '65': [0,0,1,1,1],
        '66': [0,1,0,0,0],
        '67': [0,1,0,0,1],
        '68': [0,1,0,1,0],
        '69': [0,1,0,1,1],
        '70': [0,1,1,0,0],
        '71': [0,1,1,0,1],
        '72': [0,1,1,1,0],
        '73': [0,1,1,1,1],
        '74': [1,0,0,0,0],
        '75': [1,0,0,0,1],
        '76': [1,0,0,1,0],
        '77': [1,0,1,0,0],
        '78': [1,0,1,1,0],
        '79': [1,0,1,1,1],
        '80': [1,1,0,0,0],
        '81': [1,1,0,0,1],
        '82': [1,1,0,1,0],
        '83': [1,1,0,1,1],
        '84': [1,1,1,0,0],
        '85': [1,1,1,0,1],
        '86': [1,1,1,1,0]
    }
    
    code_parts['TEMP'] = tempMap[args.temp][0:4]
    code_parts['SPCL'][1] = tempMap[args.temp][4]
    
    resText += args.temp + 'f / '

    match args.mode: #m, e, s, c, f, d
        case 'm':
            code_parts['MODE'] = [0,0,0,0]
            resText += 'max cool / '
        case 'e':
            code_parts['MODE'] = [0,1,1,0]
            resText += 'energy save / '
        case 's':
            code_parts['SPCL'] = [1,0,1,0]
            code_parts['MODE'] = [0,0,0,0]
            resText += 'sleep mode / '
        case 'c':
            code_parts['SPCL'] = [1,0,1,1]
            code_parts['MODE'] = [0,0,0,0]
            resText += 'clear sleep mode / '
        case 'f':
            code_parts['MODE'] = [0,1,0,1]
            resText += 'fan only / '
        case 'd':
            code_parts['MODE'] = [0,0,0,1]
            resText += 'dry mode / '
            
    match args.fan:
        case '1':
            code_parts['FANS'] = [0,0,0,0]
            resText += 'low fan'
        case '2': 
            code_parts['FANS'] = [0,0,1,0]
            resText += 'med fan'
        case '3':
            code_parts['FANS'] = [0,1,0,0]
            resText += 'hi fan'
            
    print(resText)

cmd = []
for i, (k,v) in enumerate(code_parts.items()):
    cmd += v

cmd += getChecksum(cmd) #Add the checksum

printCmd(cmd)
   
xmitcmd(cmd)