RPi active cooling

Description

Script that controls Raspberry Pi fan depending on the GPU temperature measurement.

Tested on Raspberry Pi 4B with Raspbian installed but it should work on any Raspberry with VideoCore GPU

Requires vcgencmd and gpio (wiringPi utility) to be available on the system (should be already installed on Raspbian)

Note: Make sure that user running the script is in the video group to be able to execute vcgencmd and gpio group to be able to control GPIO pins without sudo

sudo usermod -aG video,gpio {username}

Installation

npm install -g rpi-active-cooling

Usage

rpiac {gpio} {min} {max}

example

rpiac 18 55 70

gpio - GPIO pin to control the fan (BCM ordering)

max - temperature ('C) above which fan is enabled

min - temperature ('C) below which fan is disabled

Required electronic adjustments

If your fan does not have a built-in control wire you need to add a transistor switch to the ground wire to be able to control the fan programatically.

See the scheme below

Running as a systemd service

Create a service unit file

sudo nano /etc/systemd/system/rpiac.service

Paste content replacing user pi with your own

Description=Raspberry Pi Active Cooling
After=network.target
[Service]
ExecStart=rpiac 18 55 70
User=pi
[Install]
WantedBy=multi-user.target

Then enable and start service

sudo systemctl enable rpiac
sudo systemctl start rpiac

Known issues

Make sure you have the latest wiringPi, otherwise GPIO control might not work on Raspberry Pi 4B

http://wiringpi.com/wiringpi-updated-to-2-52-for-the-raspberry-pi-4b/