Dependency

tl;dr

Fedora

# Install dependencies
sudo dnf -y install lm_sensors

# Running sensors-detect is required to make freon work
sudo sensors-detect --auto

Debian & Ubuntu

# Install dependencies
sudo apt install lm-sensors

# Running sensors-detect is required to make freon work
sudo sensors-detect --auto

GNOME

This is a GNOME Shell extension, so of course you need gnome-shell installed. For packagers, you probably also want to require gnome-shell-extension-common. Check the shell-version property in Freon's metadata.json file to see the minimum version of GNOME Shell required.

CPU temperature, voltage and fan RPM

Required: lm-sensors -- which provides the commands sensors and sensors-detect. Before using either Freon or lm-sensors directly, you need to run sensors-detect, which runs a scan to see what hardware sensors are available. Afterward, the sensors command shows a snapshot of the current CPU core temperatures and other information; Freon uses this to display CPU and fan info. See their official website, if you want to learn more about how lm-sensors itself works. The Arch wiki may be useful too. EGO-36 use lm-sensors version 3.5.0 or higher.

Disk/SSD temperature

For storage devices, you have more options. Hard disks and solid state drives connected by SATA or IDE can use any of the following:

• udisks2, which provides a backend for getting the device's SMART data. This is the default in Freon.
• smartctl from smartmontools, another option for accessing native SMART data.
• or, alternatively, both hddtemp and gnu-netcat -- so that you can run a command like nc localhost 7634. Using this method, you will need to enable the hddtemp daemon.

Solid state storage devices connected by NVMe can use nvme-cli.

Graphics card temperature

The dependency here depends on which graphics card you have in your computer... You should only need one of these options:

• For regular Nvidia GeForce cards, you need the nvidia-smi application, which requires and is normally provided with their proprietary driver. Unfortunately, Nouveau won't work.
• For Nvidia Optimus cards, which are a hybrid of Nvidia and Intel graphics devices, you will need the the normal Nvidia driver plus bumblebee, which allows commands like optirun nvidia-smi -L and optirun nvidia-smi -q -d TEMPERATURE. See the Bumblebee home page and/or the Arch wiki for more information about how Optimus and Bumblebee work on Linux.
• For AMD Radeon cards, you need nothing more than lm-sensors to be installed.
  You should not use the Catalyst option which is for the obsolete fglrx driver, unless you are the last man standing with that driver because of a specific niche need.