为树莓派增加触摸开关

准备 ：

1. 触摸开关模块‘
2. [RPi.GPIO 0.6.2] (https://pypi.python.org/pypi/RPi.GPIO/)

代码 ：

#!/usr/bin/python
# -*- coding: utf-8 -*-
#filename:touch_switch.py
#author  yizhilaolihua

import time
try:
    import RPi.GPIO as GPIO
except RuntimeError:
    print("Error importing RPi.GPIO!  This is probably because you need superuser privileges.  You can achieve this by using 'sudo' to run your script")
class touch_switch():
    open_state = 0
    close_state = 1
    pin_num = 16
    @staticmethod
    def init():
        GPIO.setmode(GPIO.BOARD)
        GPIO.setup(touch_switch.pin_num, GPIO.IN)

    @staticmethod
    #打开返回true，timeout设置为123456时一直检测直到触摸返回true，timeout是非123456的正数a时循环检测2a次后返回false(如果一直不触碰)，
    def check_touch(timeout = 123456):
        try:
            if timeout == 123456 :
                while(1):
                    if GPIO.input(touch_switch.pin_num) == touch_switch.open_state:
                        return True
                    time.sleep(0.5)
                    
            elif timeout>0:
                while(timeout):
                    if GPIO.input(touch_switch.pin_num) == touch_switch.open_state:
                        return True
                    timeout = timeout - 1
                    time.sleep(0.5)
                print 'time is running out!!!'
                return False
            else:
                print 'timeout is int ,it must be grater than 0 '
                return False
        except Exception, e:
            print e
            return False

if __name__ == '__main__':
    touch_switch.init()
    print touch_switch.check_touch(10)
    print touch_switch.check_touch(123456)

备注：

1.运行sudo python setup.py install 安装RPi.GPIO 0.6.2
2.树莓派自带python gui无法运行，在命令行里输入sudo python touch_switch.py 运行
3.触摸开关是G,V,S三线的，V接3.3V，S接16脚，G接GND