How to use LIRC to transmit signals

[Juhn_hoo]

I am currently using a completely outdated system on my Odroid-C1, specifically Ubuntu 16.04.7 LTS and I am able to transmit signals without issues using lirc 0.9.0.

Without making any special changes to the /etc/lirc/hardware.conf file and using the following configuration:

#Chosen Remote Control
REMOTE="None"
REMOTE_MODULES=""
REMOTE_DRIVER=""
REMOTE_DEVICE=""
REMOTE_SOCKET=""
REMOTE_LIRCD_CONF=""
REMOTE_LIRCD_ARGS=""

#Chosen IR Transmitter
TRANSMITTER="odroid blaster"
TRANSMITTER_MODULES="lirc_odroid lirc_dev"
TRANSMITTER_DRIVER=""
TRANSMITTER_DEVICE="/dev/lirc0"
TRANSMITTER_SOCKET=""
TRANSMITTER_LIRCD_CONF=""
TRANSMITTER_LIRCD_ARGS=""

#Disable kernel support.
#Typically, lirc will disable in-kernel support for ir devices in order to
#handle them internally.  Set to false to prevent lirc from disabling this
#in-kernel support.
#DISABLE_KERNEL_SUPPORT="true"

#Enable lircd
START_LIRCD="true"

#Don't start lircmd even if there seems to be a good config file
#START_LIRCMD="false"

#Try to load appropriate kernel modules
LOAD_MODULES="true"

# Default configuration files for your hardware if any
LIRCMD_CONF=""

#Forcing noninteractive reconfiguration
#If lirc is to be reconfigured by an external application
#that doesn't have a debconf frontend available, the noninteractive
#frontend can be invoked and set to parse REMOTE and TRANSMITTER
#It will then populate all other variables without any user input
#If you would like to configure lirc via standard methods, be sure
#to leave this set to "false"
FORCE_NONINTERACTIVE_RECONFIGURATION="false"
START_LIRCMD=""
 

With an LED connected to physical pins 2 and 7, I can transmit signals using `irsend SEND_ONCE LG KEY_POWER`.

 

After a long time—and finding your website—I decided to try upgrading the system to Ubuntu 26.04... but I’m running into trouble: I can't use the LIRC-based transmitter the way I used to. I’ve spent two afternoons testing and re-testing, but I just can't get it to work like it did on the older version. Is there a way to make it work?

Many thanks for everything.

[Boardcon_yang]

The old blaster isn't coming back on 26.04, and it's worth knowing why before chasing it: "odroid blaster" wasn't a lirc configuration, it was an out-of-tree Hardkernel module (lirc_odroid) built for the 3.10 vendor kernel, and hardware.conf died with lirc 0.10 anyway. There's no modern driver for that path, so the clean way is to rebuild the transmit side on the generic kernel infrastructure.

Your LED circuit can stay exactly as it is. Declare a gpio-ir-tx node in a DT overlay on the GPIO behind pin 7 of the 40-pin header (Hardkernel's pinout will give you the GPIOX number), keep driving the LED through the same transistor/resistor from the 5V pin, and the TX side shows up as an extra /dev/lirc device. From there ir-ctl replaces irsend: capture the power code from your LG remote with any IR receiver (a $1 gpio-ir on a spare pin, or the onboard receiver if your image enables it) or pull the LG address/command from irdb, verify the LED blinks with a phone camera, then ir-ctl -S lg:: sends it. If you specifically want lircd and irsend back, modern lirc can sit on top of the same /dev/lirc0 — but for a single SEND_ONCE use case, ir-ctl alone is fewer moving parts.

One gotcha: gpio-ir-tx is bit-banged, so a heavily loaded system can stretch the first transmission now and then — a repeat usually fixes it, that's not a config error.

[Juhn_hoo]

Unless I'm mistaken, overlays cannot be used with the Odroid-C1;

 

I tried setting `overlays "gpio-ir-tx"` in the `/boot/` directory, but it had no effect—`/dev/lirc1` was not created, and I was unable to transmit signals.

 

If it’s not too much trouble, could you post a "recipe" I can follow to enable signal transmission?

 

And, in case it doesn't work, could you list potential errors to look out for?

 

Many thanks.