Update 2024-01-19: This has worked pretty well for a while, but you might be better served with my broadlink remote file. It supports more commands and features, and doesn't require the separate "on" command for non-heat modes. That project was made possible by the work here (which in turn was built on the work of others). It does however require HomeAssistant and a broadlink infrared transmitter. The code in my broadlink repo could probably be adapted relatively easily to make an updated LIRC remote with the same functionality.

This LIRC configuration file implements most of the functionality of many of the infrared remotes for Fujitsu ductless (mini-split) heat pumps and air conditioners. I've confirmed by testing codes transmitted by the following remotes:

• Fujitsu AR-REG1U

I've tested the codes against the following Fujitsu indoor units:

• ASU7RLF1

The following functions are implemented:

• Heat mode. Auto, quiet, low, medium, and high fan speeds. Temperatures 60F through 76F, in two degree increments.
• Cool mode. Auto, quiet, low, medium, and high fan speeds. Temperatures 64F through 88F, in two degree increments.
• Dry mode. Auto, quiet, low, medium, and high fan speeds. Temperatures 64F through 88F, in two degree increments.
• Fan only mode. Auto, quiet, low, medium, and high fan speeds.
• Minimum heat.
• Off.

This will run under a vanilla LIRC install. I've been using it on a Raspberry Pi with a homebuilt transmitter running off the GPIO pins, but any off the shelf transmitter that's LIRC compatible should work (I don't know if any of these transmitters choke on codes longer than 128 bits--if they do they won't work with these codes). Once LIRC is running, install the lircd.conf file (or copy contents over if you need other remotes). Don't forget to restart lircd after changing the config file.

I have my Raspberry Pi sitting under the indoor unit and use cron to schedule irsend commands. My transmitter is very similar to this one:

https://alexba.in/blog/2013/03/09/raspberrypi-ir-schematic-for-lirc/

Except I only have one LED.

Use irsend to send the appropriate commands. The general command form is:

mode-fan_speed-temp

e.g.

heat-auto-68F

So the typical irsend command would be:

irsend send_once fujitsu_heat_ac heat-auto-68F

IMPORTANT: For any of the heat mode commands you can send them if the unit is on or off. For any of the other modes, the unit must be on before you can send commands for that mode. For convenience, I've provided "cool-on", "dry-on", and "fan-on" commands So you can start in the appropriate mode before selecting the temp and fan speed you want. cool-on and dry-on turn on the unit with auto fan speed and 88F temp. fan-on starts the unit with auto fan speed. Example usage:

irsend send_once fujitsu_heat_ac cool-on
sleep 2
irsend send_once fujitsu_heat_ac cool-high-70F

(sleep puts a two second delay between the commands)

You can use the Celcius commands by using lircd_celcius.conf file instead of lircd.conf.

List all available commands with:

irsend LIST fujitsu_heat_ac ""

Example usage:

irsend send_once fujitsu_heat_ac cool-high-21C

Details on which commands and parameters are available.

In all commands below, fan speed is to be replaced with one of the following values:

• auto
• high
• medium
• low
• quiet

and temp is to be replaced with one of the following range of values, depending on mode:

example: cool-high-72F

• Note that in heat mode the units will heat up to 88F, but I've only included commands up to 76F. Auto fan speed in heat mode supports up to 80F.
• Temperature doesn't matter in fan mode but we send a value of 64F since we have to send something.
• I have no plans to implement "auto" mode or swing at the moment.

Thanks to the good folks on the LIRC mailing list for advice on how to approach this (particularly Alec Leamas and Bengt Martensson). I have liberally used AnalysIR and IrScrutinizer to figure this stuff out and/or generate the appropriate codes. This document from dabrams on remotecentral.com was also invaluable:

https://old.ercoupe.com/audio/FujitsuIR.pdf