Code to help with sticking to the 20-20-20 rule.

202020.py

# Combat Computer Vision Syndrome using the 20-20-20 rule
# Every 20 minutes, spend 20 seconds looking at something 20 feet away, minimum.
# https://www.vsp.com/computer-vision-syndrome.html
# @timkofu, 2016

import subprocess
import time
import sys
import os


if __name__ == "__main__":

    try:

        mpg123 = subprocess.check_output(
            "which mpg123", shell=True
        ).strip().decode("utf-8")
        notification_sound = os.path.join(
            os.path.dirname(os.path.abspath(__file__)), "notification.mp3"
        )

        with open(os.devnull, "w") as trashcan:

            notify = lambda: subprocess.call(
                [mpg123, "-q", notification_sound],
                stdout=trashcan,
                stderr=subprocess.STDOUT
            )

            # Here we go:
            notify()
            while True:
                time.sleep(60*20) # 20 minutes
                notify()
                for _ in range(20):
                    time.sleep(1)
                notify()

    except KeyboardInterrupt:
        sys.exit(0)