【发布时间】：2019-03-26 10:19:55
【问题描述】：
我正在尝试通过 Python 打开和关闭电磁阀。可以在实验开始之前使用信息框定义此切换模式。例如，我可以定义可以发生多少时间切换（切换次数）或切换将发生多长时间（切换时间以秒为单位）。我正在向 Arduino 发送两个字节，一个用于通道选择（1 到 8），第二个用于状态（0 或 1）。
切换的数量完美无缺。在 while 循环中，我给出了指令 myTime > 0 并且在每次切换期间我将其减一。因此，while 循环将一直运行，直到 myTime 或 Number of toggles 变为零。
但是当我试图从信息框给时间时，它变成了一个无限循环。我可以从信息框给出时间并将其添加到 time.time() 并尝试在 while 循环中进行比较，并希望在 time.time() 大于所需时间时终止循环。
如何确保可以同时使用这两个条件来终止 while 循环？
Python code:
from __future__ import absolute_import, division, print_function
import serial
from time import sleep
import struct
from psychopy import core, data, event, gui, visual
import time
try:
arduino = serial.Serial('COM8',19200)
sleep(2)
print("Connection to " + 'COM8' + " established succesfully!\n")
except Exception as e:
print(e)
global command
## create a DlgFromDict
info = {'Observer':'jwp', 'Channel':['1','2','3','4','5','6','7','8'],
'BreathingCycle':4, 'Timer': 0, 'ExpVersion': 1.1, 'Debug Mode': True}
infoDlg = gui.DlgFromDict(dictionary=info, title='TestExperiment',
order=['ExpVersion', 'Observer'],
tip={'Observer': 'trained visual observer, initials'},
fixed=['ExpVersion'])
myChannel = info['Channel']
myTime = info ['BreathingCycle']
myTimer = info ['Timer']
win = visual.Window(fullscr=True, size=(1536, 864), monitor='laptop')
#TODO: handle in a different way the screen resolution
instruction1 = visual.TextStim(win, text=u"""Valve on!""")
instruction2 = visual.TextStim(win, text=u"""Valve off!""")
instruction3 = visual.TextStim(win, text=u"""Thank you!""")
if infoDlg.OK:
Mytimer = time.time() + myTimer
while (myTime > 0 or time.time() < Mytimer):
if myChannel == '1':
if u'i' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',513))
myTime = myTime - 1
instruction1.draw()
win.flip()
if u'e' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',512))
myTime = myTime - 1
instruction2.draw()
win.flip()
elif myChannel == '2':
if u'i' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',257))
myTime = myTime - 1
instruction1.draw()
win.flip()
if u'e' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',256))
myTime = myTime - 1
instruction2.draw()
win.flip()
elif myChannel == '3':
if u'i' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',2049))
myTime = myTime - 1
instruction1.draw()
win.flip()
if u'e' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',2048))
myTime = myTime - 1
instruction2.draw()
win.flip()
elif myChannel == '4':
if u'i' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',1025))
myTime = myTime - 1
instruction1.draw()
win.flip()
if u'e' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',1024))
myTime = myTime - 1
instruction2.draw()
win.flip()
elif myChannel == '5':
if u'i' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',4097))
myTime = myTime - 1
instruction1.draw()
win.flip()
if u'e' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',4096))
myTime = myTime - 1
instruction2.draw()
win.flip()
elif myChannel == '6':
if u'i' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',8193))
myTime = myTime - 1
instruction1.draw()
win.flip()
if u'e' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',8192))
myTime = myTime - 1
instruction2.draw()
win.flip()
elif myChannel == '7':
if u'i' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',32769))
myTime = myTime - 1
instruction1.draw()
win.flip()
if u'e' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',32768))
myTime = myTime - 1
instruction2.draw()
win.flip()
elif myChannel == '8':
if u'i' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',16385))
myTime = myTime - 1
instruction1.draw()
win.flip()
if u'e' in event.waitKeys():
command = arduino.write(struct.pack(u'>H',16384))
myTime = myTime - 1
instruction2.draw()
win.flip()
win.close ()
arduino.close()
【问题讨论】：
-
您发布的代码缩进不一致 - 有时看起来像 4 个空格，有时是 8 个。确保您尝试运行的代码始终使用一种约定。建议使用 4 个空格，而不是制表符。
-
另外，您的八个不同
myChannel案例之间的唯一区别似乎是struct.pack参数中的数值。您是否有充分的理由不能只查找这些值，例如从以myChannel为键的字典中，然后将它们传递给此代码的单个副本？这样做可能会减少你犯错误的机会。 -
@nekomatic 是的，你是对的。我必须改变，但这不是问题。
-
@nekomatic mapped.pack 将这些数字打包成两个字节并将其发送到 Arduino，在那里我将第一个字节作为通道号读取，例如 1、2、4、8 等等，第二个byte 用于 1 或 0 来切换状态。不过，这也不是问题。