Script to easily send keys via IR led, includes (unmodified) irrp.py pigpio lib demo, as well as codes file created by it

irplay

#!/usr/bin/bash

clean=0; if [ ! -f /var/run/pigpio.pid ]; then sudo pigpiod; clean=1; fi

# script from http://abyz.me.uk/rpi/pigpio/code/irrp_py.zip
script="/irrp\.py$/,/Disconnect/p"

# json created with "./irrp.py -r -g17 -fcodes 1 3"
json="/^{/,/\]}/p"

python <(sed -n "$script" $0) -p -g26 -f<(sed -n "$json" $0) $1

if [ $clean -eq 1 ]; then sudo killall pigpiod; fi

exit

{"1": [9039, 4419, 630, 513, 630, 513, 630, 513, 630, 513, 630, 513, 630, 513, 630, 513, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 513, 630, 513, 630, 1623, 630, 513, 630, 513, 630, 1623, 630, 513, 630, 513, 630, 513, 630, 1623, 630, 513, 630, 1623, 630, 1623, 630, 513, 630, 1623, 630, 1623, 630, 1623, 630],
 "3": [9039, 4419, 630, 513, 630, 513, 630, 513, 630, 513, 630, 513, 630, 513, 630, 513, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 513, 630, 513, 630, 1623, 630, 513, 630, 513, 630, 513, 630, 513, 630, 513, 630, 513, 630, 1623, 630, 513, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630, 1623, 630]}

#!/usr/bin/env python

# irrp.py
# 2015-12-21
# Public Domain

"""
A utility to record and then playback IR remote control codes.

To record use

./irrp.py -r -g4 -fcodes 1 2 3 4 5 6

where

-r record
-g the GPIO connected to the IR receiver
-f the file to store the codes

and 1 2 3 4 5 6 is a list of codes to record.

To playback use

./irrp.py -p -g17 -fcodes 2 3 4

where

-p playback
-g the GPIO connected to the IR transmitter
-f the file storing the codes to transmit

and 2 3 4 is a list of codes to transmit.

OPTIONS

-r record
-p playback
-g GPIO (receiver for record, transmitter for playback)
-f file

id1 id2 id3 list of ids to record or transmit

RECORD

--glitch     ignore edges shorter than glitch microseconds, default 100 us
--post       expect post milliseconds of silence after code, default 15 ms
--pre        expect pre milliseconds of silence before code, default 200 ms
--short      reject codes with less than short pulses, default 10
--tolerance  consider pulses the same if within tolerance percent, default 15
--no-confirm don't require a code to be repeated during record

TRANSMIT

--freq       IR carrier frequency, default 38 kHz
--gap        gap in milliseconds between transmitted codes, default 100 ms
"""

import time
import json
import os
import argparse

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

p = argparse.ArgumentParser()

g = p.add_mutually_exclusive_group(required=True)
g.add_argument("-p", "--play",   help="play keys",   action="store_true")
g.add_argument("-r", "--record", help="record keys", action="store_true")

p.add_argument("-g", "--gpio", help="GPIO for RX/TX", required=True, type=int)
p.add_argument("-f", "--file", help="Filename",       required=True)

p.add_argument('id', nargs='+', type=str, help='IR codes')

p.add_argument("--freq",      help="frequency kHz",   type=float, default=38.0)

p.add_argument("--gap",       help="key gap ms",        type=int, default=100)
p.add_argument("--glitch",    help="glitch us",         type=int, default=100)
p.add_argument("--post",      help="postamble ms",      type=int, default=15)
p.add_argument("--pre",       help="preamble ms",       type=int, default=200)
p.add_argument("--short",     help="short code length", type=int, default=10)
p.add_argument("--tolerance", help="tolerance percent", type=int, default=15)

p.add_argument("-v", "--verbose", help="Be verbose",     action="store_true")
p.add_argument("--no-confirm", help="No confirm needed", action="store_true")

args = p.parse_args()

GPIO       = args.gpio
FILE       = args.file
GLITCH     = args.glitch
PRE_MS     = args.pre
POST_MS    = args.post
FREQ       = args.freq
VERBOSE    = args.verbose
SHORT      = args.short
GAP_MS     = args.gap
NO_CONFIRM = args.no_confirm
TOLERANCE  = args.tolerance

POST_US    = POST_MS * 1000
PRE_US     = PRE_MS  * 1000
GAP_S      = GAP_MS  / 1000.0
CONFIRM    = not NO_CONFIRM
TOLER_MIN =  (100 - TOLERANCE) / 100.0
TOLER_MAX =  (100 + TOLERANCE) / 100.0

last_tick = 0
in_code = False
code = []
fetching_code = False

def backup(f):
   """
   f -> f.bak -> f.bak1 -> f.bak2
   """
   try:
      os.rename(os.path.realpath(f)+".bak1", os.path.realpath(f)+".bak2")
   except:
      pass

   try:
      os.rename(os.path.realpath(f)+".bak", os.path.realpath(f)+".bak1")
   except:
      pass

   try:
      os.rename(os.path.realpath(f), os.path.realpath(f)+".bak")
   except:
      pass

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 normalise(c):
   """
   Typically a code will be made up of two or three distinct
   marks (carrier) and spaces (no carrier) of different lengths.

   Because of transmission and reception errors those pulses
   which should all be x micros long will have a variance around x.

   This function identifies the distinct pulses and takes the
   average of the lengths making up each distinct pulse.  Marks
   and spaces are processed separately.

   This makes the eventual generation of waves much more efficient.

   Input

     M    S   M   S   M   S   M    S   M    S   M
   9000 4500 600 540 620 560 590 1660 620 1690 615

   Distinct marks

   9000                average 9000
   600 620 590 620 615 average  609

   Distinct spaces

   4500                average 4500
   540 560             average  550
   1660 1690           average 1675

   Output

     M    S   M   S   M   S   M    S   M    S   M
   9000 4500 609 550 609 550 609 1675 609 1675 609
   """
   if VERBOSE:
      print("before normalise", c)
   entries = len(c)
   p = [0]*entries # Set all entries not processed.
   for i in range(entries):
      if not p[i]: # Not processed?
         v = c[i]
         tot = v
         similar = 1.0

         # Find all pulses with similar lengths to the start pulse.
         for j in range(i+2, entries, 2):
            if not p[j]: # Unprocessed.
               if (c[j]*TOLER_MIN) < v < (c[j]*TOLER_MAX): # Similar.
                  tot = tot + c[j]
                  similar += 1.0

         # Calculate the average pulse length.
         newv = round(tot / similar, 2)
         c[i] = newv

         # Set all similar pulses to the average value.
         for j in range(i+2, entries, 2):
            if not p[j]: # Unprocessed.
               if (c[j]*TOLER_MIN) < v < (c[j]*TOLER_MAX): # Similar.
                  c[j] = newv
                  p[j] = 1

   if VERBOSE:
      print("after normalise", c)

def compare(p1, p2):
   """
   Check that both recodings correspond in pulse length to within
   TOLERANCE%.  If they do average the two recordings pulse lengths.

   Input

        M    S   M   S   M   S   M    S   M    S   M
   1: 9000 4500 600 560 600 560 600 1700 600 1700 600
   2: 9020 4570 590 550 590 550 590 1640 590 1640 590

   Output

   A: 9010 4535 595 555 595 555 595 1670 595 1670 595
   """
   if len(p1) != len(p2):
      return False

   for i in range(len(p1)):
      v = p1[i] / p2[i]
      if (v < TOLER_MIN) or (v > TOLER_MAX):
         return False

   for i in range(len(p1)):
       p1[i] = int(round((p1[i]+p2[i])/2.0))

   if VERBOSE:
      print("after compare", p1)

   return True

def tidy_mark_space(records, base):

   ms = {}

   # Find all the unique marks (base=0) or spaces (base=1)
   # and count the number of times they appear,

   for rec in records:
      rl = len(records[rec])
      for i in range(base, rl, 2):
         if records[rec][i] in ms:
            ms[records[rec][i]] += 1
         else:
            ms[records[rec][i]] = 1

   if VERBOSE:
      print("t_m_s A", ms)

   v = None

   for plen in sorted(ms):

      # Now go through in order, shortest first, and collapse
      # pulses which are the same within a tolerance to the
      # same value.  The value is the weighted average of the
      # occurences.
      #
      # E.g. 500x20 550x30 600x30  1000x10 1100x10  1700x5 1750x5
      #
      # becomes 556(x80) 1050(x20) 1725(x10)
      #       
      if v == None:
         e = [plen]
         v = plen
         tot = plen * ms[plen]
         similar = ms[plen]

      elif plen < (v*TOLER_MAX):
         e.append(plen)
         tot += (plen * ms[plen])
         similar += ms[plen]

      else:
         v = int(round(tot/float(similar)))
         # set all previous to v
         for i in e:
            ms[i] = v
         e = [plen]
         v = plen
         tot = plen * ms[plen]
         similar = ms[plen]

   v = int(round(tot/float(similar)))
   # set all previous to v
   for i in e:
      ms[i] = v

   if VERBOSE:
      print("t_m_s B", ms)

   for rec in records:
      rl = len(records[rec])
      for i in range(base, rl, 2):
         records[rec][i] = ms[records[rec][i]]

def tidy(records):

   tidy_mark_space(records, 0) # Marks.

   tidy_mark_space(records, 1) # Spaces.

def end_of_code():
   global code, fetching_code
   if len(code) > SHORT:
      normalise(code)
      fetching_code = False
   else:
      code = []
      print("Short code, probably a repeat, try again")

def cbf(gpio, level, tick):

   global last_tick, in_code, code, fetching_code

   if level != pigpio.TIMEOUT:

      edge = pigpio.tickDiff(last_tick, tick)
      last_tick = tick

      if fetching_code:

         if (edge > PRE_US) and (not in_code): # Start of a code.
            in_code = True
            pi.set_watchdog(GPIO, POST_MS) # Start watchdog.

         elif (edge > POST_US) and in_code: # End of a code.
            in_code = False
            pi.set_watchdog(GPIO, 0) # Cancel watchdog.
            end_of_code()

         elif in_code:
            code.append(edge)

   else:
      pi.set_watchdog(GPIO, 0) # Cancel watchdog.
      if in_code:
         in_code = False
         end_of_code()

pi = pigpio.pi() # Connect to Pi.

if not pi.connected:
   exit(0)

if args.record: # Record.

   try:
      f = open(FILE, "r")
      records = json.load(f)
      f.close()
   except:
      records = {}

   pi.set_mode(GPIO, pigpio.INPUT) # IR RX connected to this GPIO.

   pi.set_glitch_filter(GPIO, GLITCH) # Ignore glitches.

   cb = pi.callback(GPIO, pigpio.EITHER_EDGE, cbf)

   # Process each id

   print("Recording")
   for arg in args.id:
      print("Press key for '{}'".format(arg))
      code = []
      fetching_code = True
      while fetching_code:
         time.sleep(0.1)
      print("Okay")
      time.sleep(0.5)

      if CONFIRM:
         press_1 = code[:]
         done = False

         tries = 0
         while not done:
            print("Press key for '{}' to confirm".format(arg))
            code = []
            fetching_code = True
            while fetching_code:
               time.sleep(0.1)
            press_2 = code[:]
            the_same = compare(press_1, press_2)
            if the_same:
               done = True
               records[arg] = press_1[:]
               print("Okay")
               time.sleep(0.5)
            else:
               tries += 1
               if tries <= 3:
                  print("No match")
               else:
                  print("Giving up on key '{}'".format(arg))
                  done = True
               time.sleep(0.5)
      else: # No confirm.
         records[arg] = code[:]

   pi.set_glitch_filter(GPIO, 0) # Cancel glitch filter.
   pi.set_watchdog(GPIO, 0) # Cancel watchdog.

   tidy(records)

   backup(FILE)

   f = open(FILE, "w")
   f.write(json.dumps(records, sort_keys=True).replace("],", "],\n")+"\n")
   f.close()

else: # Playback.

   try:
      f = open(FILE, "r")
   except:
      print("Can't open: {}".format(FILE))
      exit(0)

   records = json.load(f)

   f.close()

   pi.set_mode(GPIO, pigpio.OUTPUT) # IR TX connected to this GPIO.

   pi.wave_add_new()

   emit_time = time.time()

   if VERBOSE:
      print("Playing")

   for arg in args.id:
      if arg in records:

         code = records[arg]

         # Create wave

         marks_wid = {}
         spaces_wid = {}

         wave = [0]*len(code)

         for i in range(0, len(code)):
            ci = code[i]
            if i & 1: # Space
               if ci not in spaces_wid:
                  pi.wave_add_generic([pigpio.pulse(0, 0, ci)])
                  spaces_wid[ci] = pi.wave_create()
               wave[i] = spaces_wid[ci]
            else: # Mark
               if ci not in marks_wid:
                  wf = carrier(GPIO, FREQ, ci)
                  pi.wave_add_generic(wf)
                  marks_wid[ci] = pi.wave_create()
               wave[i] = marks_wid[ci]

         delay = emit_time - time.time()

         if delay > 0.0:
            time.sleep(delay)

         pi.wave_chain(wave)

         if VERBOSE:
            print("key " + arg)

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

         emit_time = time.time() + GAP_S

         for i in marks_wid:
            pi.wave_delete(marks_wid[i])

         marks_wid = {}

         for i in spaces_wid:
            pi.wave_delete(spaces_wid[i])

         spaces_wid = {}
      else:
         print("Id {} not found".format(arg))

pi.stop() # Disconnect from Pi.

For use in Pi400 KVM; irplay is used to switch display when keyboard and mouse get switched between Pi400 and laptop:
https://forums.raspberrypi.com/viewtopic.php?f=140&t=295074&start=50#p1924368