fand - A simple, flexible fan control daemon

Introduction

fand is a daemon that controls the fans (and other pwm-controlled devices) in your system. It's main feature is its configurability, using a concept of thermal zones.

Features

• Configurability
• Fan curve interpolation
• Supports stable hwmon paths
• Lightweight, written in C with minimum dependencies

Zones

A zone is a collection of fans and sensors. Each sensor in a zone is polled, optionally has an offset applied, and the maximum sensor value in a zone is used to control the fans in the zone. Each fan has a curve, defined as a list of temperatures and the respective PWM values to be applied. For temperatures inbetween the defined curve points, the PWM values are interpolated automatically.

This allows you to:

• have your case fans follow both CPU temperatures and GPU temperatures
• set your AIO cooler fan speeds to follow the coolant temperatures, but also ramp up when the GPU gets hot
• have your pump speed follow the CPU temperatures but stay high when the coolant is warm
• all of the above, simultaneously!

Example

A simple config with one sensor and 2 fans:

zones:
(
  { # Zone #1
    sensors:
    (
      { # NZXT Kraken coolant temperature
        path: "/sys/class/hwmon/hwmon7"
        index: 1
        offset: 0
      }
    )

    fans:
    (
      { # NCT6798 fan header #1
        path: "/sys/class/hwmon/hwmon5"
        index: 1
        curve: {
          temperatures: [ 25, 30, 37, 40 ]
          speeds: [ 55, 80, 220, 255 ]
        }
      },
      { # NCT6798 fan header #2
        path: "/sys/class/hwmon/hwmon5"
        index: 2
        curve: {
          temperatures: [ 25, 30, 37, 40 ]
          speeds: [ 55, 80, 220, 255 ]
        }
      }
    )
  }
)

Dependencies

• libconfig

Limitations

• Only hwmon fans and sensors are supported
• Each zone has to have at least one fan and at least one sensor
• A fan can't be used in more than one zone (well, it can, it's just that only the last setting will be applied)