eyes_rest.py

import cv2
import time
import easygui

face_cascade = cv2.CascadeClassifier('data/haarcascades/haarcascade_frontalface_default.xml')

cap = cv2.VideoCapture(0)

last_time = time.time()
elapse = 0

while True:
    if elapse <= 20*60:
        ret, img = cap.read()
        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
        faces = face_cascade.detectMultiScale(gray, 1.3, 5)
        if faces != ():
            elapsePerFrame = time.time() - last_time
            elapse += elapsePerFrame
            print('You stared at the screen for {} seconds now.'.format(round(elapse, 2)))
            last_time = time.time()
        else:
            print('eyes not detect')
            last_time = time.time()
        time.sleep(1)
    else :
        print('Rest your eye!')
        easygui.msgbox('Rest your eye!', 'Eye love you!')
        time.sleep(20)
        easygui.msgbox('It\'s OK now.', 'Eye love you!')
        elapse = 0
        last_time = time.time()