指纹传感器上无输入 15 秒后退出指纹程序 PYTHON

Question

:) 我有一个我自己无法解决的问题（我用 time.time() 尝试了很多，但我从来没有解决过我的问题）。如果 15 秒过去了，我希望我的程序退出并停止等待手指。如果有人知道如何在 python 中做到这一点，我将非常高兴和感激！非常感谢！有问题就问我吧！代码在下面！

import sys
import os
sys.path.insert(0, '/home/pi/scripts')
import subprocess
import lcddriver
from time import *


lcd = lcddriver.lcd()
lcd.lcd_clear()

import hashlib
from pyfingerprint.pyfingerprint import PyFingerprint


## Tries to initialize the sensor
try:
f = PyFingerprint('/dev/ttyUSB0', 57600, 0xFFFFFFFF, 0x00000000)

if ( f.verifyPassword() == False ):
    raise ValueError('The given fingerprint sensor password is wrong!')

except Exception as e:
lcd.lcd_display_string('Initialization failed!', 2)
print('Exception message: ' + str(e))
exit(1)

## Gets some sensor information
print('Currently used templates: ' + str(f.getTemplateCount()) +'/'+ 
str(f.getStorageCapacity()))

## Tries to search the finger and calculate hash
try:
 f = PyFingerprint('/dev/ttyUSB0', 57600, 0xFFFFFFFF, 0x00000000)

if ( f.verifyPassword() == False ):
    raise ValueError('The given fingerprint sensor password is wrong!')

except Exception as e:
lcd.lcd_display_string('Initialization failed!', 2)
print('Exception message: ' + str(e))
exit(1)

## Gets some sensor information
print('Currently used templates: ' + str(f.getTemplateCount()) +'/'+ 
str(f.getStorageCapacity()))

## Tries to search the finger and calculate hash
try:
lcd.lcd_display_string(' Waiting for finger', 2)

## Wait that finger is read
while ( f.readImage() == False ):
    pass

## Converts read image to characteristics and stores it in charbuffer 1
f.convertImage(0x01)

## Searchs template
result = f.searchTemplate()

positionNumber = result[0]
accuracyScore = result[1]
 if ( positionNumber == -1 ):

    os.system('python access_denied.py')
    exit(0)
 else:
    lcd.lcd_clear()
    lcd.lcd_display_string("  Finger accepted!", 2)
    sleep(1.5)
    lcd.lcd_clear()
    os.system('python keypad.py')

Answer 1

你可以试试这个：

timeout = time.time() + 15 # 15s from now
while True:
   # do stuff
    end_time = time.time()
    if end_time > timeout or f.readImage():
        break
    else:
        time.sleep(0.25) # sleep to reduce CPU usage

Answer 2

您是否尝试过启动一个线程来保持时间的计数并在设定的时间后关闭程序？当读取指纹时，程序会在线程关闭程序之前关闭线程。除了一般知识外，我个人在多线程方面没有太多经验，所以我不知道如何应用它，但是这个 showld 可以帮助你 https://www.tutorialspoint.com/python/python_multithreading.htm

指纹传感器上无输入 15 秒后退出指纹程序 PYTHON

Exit program for fingerprint after 15 seconds of no input on fingerprintsensor PYTHON

python

time

fingerprint