Purpose

Make a Raspberry Pi infrared remote control. The device can programmatically control television sound bar audio volume. The Raspberry Pi uses LIRC (Linux Infrared Remote Control) to send commands to an attached infrared transmitter.

The Python app has three main parts:

Functions to send commands to the infrared transmitter, which then transmits the commands to the television sound bar
A Flask web service to accept television command requests (e.g. volume decrease, volume increase)
A scheduler that automatically sends remote control commands at programmed times (e.g. mute during TV commercials)

Results

TV Sound Bar

Polk audio

Infrared transmitter

LED IR light is invisible to human eye. iPhone 12 front facing camera doesn't filter IR. It will show IR LED blink.

Install hardware

Raspberry Pi IR Control Expansion Board. This uses gpio pins 17 out (IR LED), pin 18 in (IR receiver). http://www.raspberrypiwiki.com/index.php/Raspberry_Pi_IR_Control_Expansion_Board

I bought Icstation 38KHz IR Infrared Remote Control Transceiver Shield for Raspberry Pi 2 3 Module B B+ https://www.amazon.com/IR-Remote-Control-Transceiver-Raspberry/dp/B0713SK7RJ/ref=pd_cp_147_1?pd_rd_w=nydwe&pf_rd_p=ef4dc990-a9ca-4945-ae0b-f8d549198ed6&pf_rd_r=NPTQR2NR66SZXGEC1CFF&pd_rd_r=dc222ec9-1d1f-11e9-82b3-7117715d74e2&pd_rd_wg=OnVSD&pd_rd_i=B0713SK7RJ&psc=1&refRID=NPTQR2NR66SZXGEC1CFF

Install Raspberry Pi OS

I erased an 8 Gb SD card and installed latest version of Raspberry Pi OS. Then put it in a Raspberry Pi 3.

connect to raspberry pi

Can attach keyboard and monitor to pi. Alternatively, can connect from another computer on local network via ssh.

ssh -v pi@10.0.0.4

install dependency LIRC

Michael Traver's excellent "Raspberry Pi IR Remote Control" https://github.com/mtraver/rpi-ir-remote has helpful up to date suggestions for configuring current versions of LIRC (0.9.4) and Raspbian (Stretch) and warnings about outdated online info.

sudo apt-get install lirc
    The following additional packages will be installed:
        <list differs from 2019>

sudo apt autoremove
    Removing python-colorzero

don't install package lirc-compat-remotes

This package is outdated, contains remote definitions which were part of lirc up to 0.9.0.

enable lirc-rpi

In /boot/config.txt says # uncomment this to enable infrared communication.

Uncomment 2 lines. Required sudo.

NOTE: Swap pins 17 and 18 to match my ICStation board. Transmit tx should be pin 18.

sudo vi config.txt

dtoverlay=gpio-ir,gpio_pin=18
dtoverlay=gpio-ir-tx,gpio_pin=17

don't add or edit hardware.conf

LIRC >= 0.9.4 does not use hardware.conf

Add remote control config files

Background: lirc looks in a configuration directory for files ending in .conf

/etc/lirc/lircd.conf.d

Don't disable /etc/lirc/lircd.conf.d/devinput.lircd.conf

This is not necessary to use polk.lircd.conf https://learn.adafruit.com/using-an-ir-remote-with-a-raspberry-pi-media-center/using-other-remotes To disable a configuration file change extension from .conf to e.g. .dist

cd /etc/lirc/lircd.conf.d
sudo mv devinput.lircd.conf devinput.lircd.dist

https://sourceforge.net/projects/lirc-remotes/ has config files for many remotes. You can try any of these to see if they work with your device.

I tried cxa_cxc_cxn.lircd.conf but it didn't work with Polk sound bar. For more info see Appendix - cxa_cxc_cxn.lircd.conf

Create a custom configuration file for Polk sound bar.

Put in this repo remy_python/config for version control, and copied to /etc/lirc/lircd.conf.d For more info see Appendix - Create polk.lircd.conf

Add polk.lircd.conf

Copy from repo remy_python/config to /etc/lirc/lircd.conf.d For more info see Appendix - Create polk.lircd.conf

cd /etc/lirc/lircd.conf.d
sudo cp ~/beepscore/remy_python/config/polk.lircd.conf .

list polk configuration defined keys

irsend list polk ""

terminal output

unknown remote: "polk"

I rebooted pi, now irsend list works.

irsend list polk ""

terminal output

0000000000000001 KEY_MUTE
0000000000000002 KEY_POWER
0000000000000003 KEY_VOLUMEUP
0000000000000004 KEY_VOLUMEDOWN
0000000000000005 KEY_UP
0000000000000006 KEY_DOWN

send a key

irsend SEND_ONCE polk KEY_VOLUMEDOWN

"hardware does not support sending.
 Error running command: Input/output error"

enable transmitting

This is necessary to avoid error "hardware does not support sending". Reference https://raspberrypi.stackexchange "LIRC won't transmit (irsend: hardware does not support sending")

Make a backup copy

cd /etc/lirc
sudo cp lirc_options.conf lirc_options.conf.bak

In /etc/lirc/lirc_options.conf

change driver

driver = devinput

driver = default

The right hand side may be delimited by " i.e. driver = "default" String delimiter is not necessary (at least for filenames with no spaces) so I didn't do it.

I rebooted pi. Now hardware message doesn't appear.

Keep device = auto

device=/dev/lirc0 works but isn't necessary.

install python dependencies

venv virtual environment

This project doesn't have many dependencies, and venv is an easy way to manage them. Anaconda / conda / miniconda may work better for projects with more dependencies. If using venv, in .gitignore add a line to ignore the directory:

venv/*

Then in terminal

cd remy_python
python3 -m venv ./venv

activate

source ./venv/bin/activate

pip3 install apscheduler
pip3 install flask

To run Flask web service

connect to raspberry pi

ssh -v pi@10.0.0.4

cd to project directory

cd ~/beepscore/remy_python

activate environment

If using venv

source ./venv/bin/activate

If using conda (e.g. via miniconda)

source activate remy_python

start Flask web server

python3 service.py
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
* Restarting with stat

Now clients on local network can see the remote control service.

Can add a bash script e.g. start_remy_python.sh

give user permission to execute script

chmod u+x start_remy_python.sh

Example script

cd ~/beepscore/remy_python
# activate python virtual environment
source ./venv/bin/activate
python3 service.py

endpoints

GET

http://10.0.0.4:5000/api/v1/tv/ping/

POST

Send a remote control command.

http://10.0.0.4:5000/api/v1/tv/mute/
                    /api/v1/tv/power/
                    /api/v1/tv/voice-decrease/
                    /api/v1/tv/voice-increase/
                    /api/v1/tv/volume-decrease/
                    /api/v1/tv/volume-increase/

client

GET requests can be made via a browser such as Firefox or mobile Safari. POST requests can be made via clients such as terminal curl or POSTMAN or iOS Remy.app

curl --request POST http://10.0.0.4:5000/api/v1/tv/volume-decrease/

server log

pi terminal shows client's ip address and request info

10.0.0.3 - - [23/Jan/2019 23:39:22] "POST /api/v1/tv/volume-decrease/ HTTP/1.1" 200 -
10.0.0.3 - - [23/Jan/2019 23:39:26] "POST /api/v1/tv/volume-increase/ HTTP/1.1" 200 -

Scheduler

install apscheduler

On macOS, can install via conda navigator. However I couldn't find conda apscheduler for raspberry pi. So install via pip.

source activate remy_python
pip install apscheduler

run

To run server and scheduler

source activate remy_python
python service.py

To run scheduler but not server

source activate remy_python
python scheduler.py

adwords.txt

Currently unused. Could be used together with closed caption text or speech recognition to detect commercials. Some commercials don't say product/service/company name until late in the commercial.

unit tests

Can run tests on macOS by temporarily commenting out service.py subprocess.call(irsend). Not sure how to run tests on pi yet.

python -m unittest discover

throws RuntimeError: working outside of request context

Appendix - cxa_cxc_cxn.lircd.conf

First I tried lirc configuration file cxa_cxc_cxn.lircd.conf

pi@raspberrypi:/etc/lirc/lircd.conf.d $ sudo cp ~/beepscore/rpi-ir-remote/config/lirc/cxa_cxc_cxn.lircd.conf .

list cambridge_cxa configuration defined keys

Use lirc command irsend

irsend list cambridge_cxa ""

000000000000140c KEY_POWER
000000000000140e KEY_POWER_ON
000000000000140f KEY_POWER_OFF
000000000000140d KEY_MUTE
0000000000001432 KEY_MUTE_ON
0000000000001433 KEY_MUTE_OFF
0000000000001410 KEY_VOLUMEUP
0000000000001411 KEY_VOLUMEDOWN

send a key

irsend SEND_ONCE cambridge_cxa KEY_VOLUMEDOWN

The front facing camera on iPhone showed the raspberry pi is lighting the transmit infrared LED. However the remote configuration cambridge_cxa doesn't work with my Polk sound bar receiver.

Appendix - Create polk.lircd.conf

Create a custom lirc config file for Polk sound bar.

Disable incorrect remote configuration files

https://learn.adafruit.com/using-an-ir-remote-with-a-raspberry-pi-media-center/using-other-remotes To disable a configuration file change extension from .conf to e.g. .dist

cd /etc/lirc/lircd.conf.d
sudo mv devinput.lircd.conf devinput.lircd.dist

Use infrared receiver to generate a new configuration file.

lirc-remotes has lots of files, but none named polk. Could try existing ones but this could be time consuming. Instead use an existing handheld remote transmitter to "teach" the Raspberry Pi how to act like that remote. The Raspberry Pi IR Control Expansion Board has an infrared receiver. LIRC command irrecord records button press infrared signals. http://www.lirc.org/html/irrecord.html

irrecord error need to stop lirc daemon

irrecord -d /dev/lirc0 ~/lircd.conf

Using driver default on device /dev/lirc0
Could not init hardware (lircd running ? --> close it, check permissions)

view running processes

htop
^C

stop lirc daemon process by name

sudo killall -9 lircd

list valid key names that are available to be assigned to a remote configuration file

irrecord --list-namespace

irrecord -d didn't work with polk remote, it never got enough info to make a .conf file.

In repo remy_python I added directory config to keep polk.lircd.conf in version control.

cd remy_python/config
irrecord -d /dev/lirc0 ./polk.lircd.conf

fix recording failing using option -f --force raw mode

irrecord -f -d /dev/lirc0 ~/polk.lircd.conf

Enter valid key names e.g. KEY_VOLUMEDOWN

For LIRC to use configuration file, copied it to

/etc/lirc/lircd.conf.d/polk.lircd.conf

add more keys using option -u --update

cd remy_python/config
irrecord -f -u ./polk.lircd.conf

Then copy updated file to

/etc/lirc/lircd.conf.d/polk.lircd.conf

list polk configuration defined keys

irsend list polk ""

0000000000000001 KEY_MUTE
0000000000000002 KEY_POWER
0000000000000003 KEY_VOLUMEUP
0000000000000004 KEY_VOLUMEDOWN
0000000000000005 KEY_UP
0000000000000006 KEY_DOWN