Cold down the temperature of OPi automatically.

opi_fan.py

#!/usr/bin/python3

# opi_fan - Cold down the temperature of OPi automatically.
# License: MIT (https://ncurl.xyz/s/RD0Yl5fSg)
# https://gist.github.com/supersonictw/046e10024038c18ccb46cbf3f1a88b79

from sys import argv
from time import sleep

from gpiod import (
    request_lines,
    LineSettings
)
from gpiod.line import (
    Direction,
    Value,
)

""" /usr/local/sbin/opi_fan
#!/bin/sh
BASE_DIR="/opt/opi_fan"

INTERPRETER="$BASE_DIR/venv/bin/python"
CONTROLLER="$BASE_DIR/main.py"

"$INTERPRETER" "$CONTROLLER" $1
"""

""" /lib/systemd/system/opi_fan.service
[Unit]
Description=Cold down the temperature of OPi automatically.
After=multi-user.target

[Service]
Type=simple
ExecStart=/usr/local/sbin/opi_fan daemon

[Install]
WantedBy=multi-user.target
"""


CHECK_TIME_GAP = 60

FAN_CONTROL_PIN = 6
FAN_ENABLE_TEMPERATURE = 60

COLD_TEMPERATURE_GAP = 10

SYS_GPIO_CHIP_FILE = "/dev/gpiochip0"
SYS_TEMPERATURE_FILE = "/sys/devices/virtual/thermal/thermal_zone0/temp"


class Fan:
    def __init__(self) -> None:
        self.request = request_lines(
            SYS_GPIO_CHIP_FILE,
            consumer="opi_fan",
            config={
                FAN_CONTROL_PIN: LineSettings(
                    direction=Direction.OUTPUT,
                    output_value=Value.INACTIVE
                )
            },
        )

    def enable(self):
        self.request.set_value(
            FAN_CONTROL_PIN,
            Value.ACTIVE,
        )

    def disable(self):
        self.request.set_value(
            FAN_CONTROL_PIN,
            Value.INACTIVE,
        )

    def cleanup(self):
        self.disable()
        self.request.release()


def temperature_read():
    with open(SYS_TEMPERATURE_FILE, "r") as f:
        temperature = f.read()
        return int(temperature) / 1000


def temperature_loop():
    while temperature_read() > (FAN_ENABLE_TEMPERATURE - COLD_TEMPERATURE_GAP):
        sleep(CHECK_TIME_GAP)


def task_cold():
    fan = Fan()
    try:
        fan.enable()
        while True:
            sleep(CHECK_TIME_GAP)
    except KeyboardInterrupt:
        print("Task interrupted.")
    finally:
        fan.cleanup()


def task_daemon():
    fan = Fan()
    while True:
        if temperature_read() < FAN_ENABLE_TEMPERATURE:
            sleep(CHECK_TIME_GAP)
            continue

        fan.enable()
        temperature_loop()
        fan.disable()


def task_temp():
    temperature = temperature_read()
    print(f"{temperature:.1f}°C")


if __name__ == '__main__':
    command_tasks = {
        "cold": task_cold,
        "daemon": task_daemon,
        "temp": task_temp,
    }
    if len(argv) > 1 and argv[1] in command_tasks:
        command_tasks[argv[1]]()
    else:
        print("No task specified.")