This repository contains code to control a Noctua PWM fan with GPIO pins, based on the CPU and ambient temperatures.

Using Noctua 5V PWM fan. Note that the circuit diagram Noctua provides as an example for driving the PWM fan is incorrect. It should be a standard CMOS inverter circuit.

Pinout for Orange Pi Plus 2 is here: https://www.meccanismocomplesso.org/en/a-look-back-at-the-orange-pi-plus-2-board/

The code for Armbian uses pyGPIO, which is not available in pip. Install as follows:

sudo apt-get install python-dev
git clone https://github.com/chwe17/pyGPIO.git
cd pyGPIO
sudo python setup.py install

fan_curve_control.py controls the fan speed, and requires a config file setting:

• Which pin to use for the PWM signal
• The location of a database to log the temperatures and fan duty cycle
• The file containing the cpu temperature

The controller sets the fan speed to run at one of three possible speeds.

Also included is a dockerised flask web app to display a graph showing measured temperatures and the duty cycle of the fan. The docker-compose.yml file requires two variables to be set in a .env file:

• The secret key for the web app
• The location of the database with the temperature and duty cycle information

The secret key is passed to the flask app in the container as an environment variable.