Home Assistant OS Pi 5 Fan Enabler

Home Assistant Add-on / App

Enables the Raspberry Pi 5's built-in fan when running Home Assistant OS.
The Raspberry Pi 5's built-in fan header is controlled by firmware, it cannot (currently) be controlled by Home Assistant.
This add-on modifies Home Assistant's boot configuration to force the fan to run. Please read the installation notes very carefully, it requires elevated permissions to run.
The configuration creates four fan speed thresholds:
35°C: 30% speed
50°C: 49% speed
60°C: 69% speed
65°C: 98% speed

Installation

Enabled Advanced Mode first - click on your username in the bottom-left corner and then toggle Advanced Mode under User Preferences.
Within Home Assistant, click Settings -> Apps -> Install App button bottom-right -> Click the three dots in the top right -> choose 'Repositories'.
Paste in the URL of this repository: https://github.com/sOckhamSter/Pi5FanEnabler
Install the "Pi 5 Fan Enabler" app/add-on and Disable Protection Mode First! Then hit the start button and observe the logs. You may uninstall the Add-On when complete.

Operation

Important Note when requested to reboot, pull the power plug from your machine and restart it, or do a full host reboot if you know how to do that. Make sure you do this twice - you must do two reboots! Hit the start button and observe the logs. You may uninstall the Add-On when complete.

Home Assistant Sensors

You can create sensors in Home Assistant to monitor the speed of the fan, both in terms of RPM and percentage of maximum speed.
First check the add-on logs and make sure that the add-on has found your fan. It should give you two paths, for example:
/sys/devices/platform/cooling_fan/hwmon/hwmon1/fan1_input
/sys/devices/platform/cooling_fan/hwmon/hwmon1/pwm1

Make a note of those and then create two new command_line sensors as follows:

command_line:
  - sensor:
      name: "Pi 5 Fan Speed (RPM)"
      icon: "mdi:fan"
      unique_id: "pi5fan_rpm"
      command: 'cat /sys/devices/platform/cooling_fan/hwmon/hwmon1/fan1_input'
      unit_of_measurement: "RPM"
      scan_interval: 15
      value_template: "{{ value | int }}"
      state_class: "measurement"
  - sensor:
      name: "Pi 5 Fan Speed (%)"
      icon: "mdi:fan"
      unique_id: "pi5fan_percentage"
      command: 'cat /sys/devices/platform/cooling_fan/hwmon/hwmon1/pwm1'
      unit_of_measurement: "%"
      scan_interval: 15
      value_template: "{{((value | int) / 255 * 100) | round(0, 'common')}}"
      state_class: "measurement"

Make sure you replace the paths in both commands to match the ones displayed in the add-on's logs.

Credits

Adapted from the work by adamoutler:
https://github.com/adamoutler/HassOSConfigurator