python - 写入串口时速度大幅降低

Question

使用 pygame 从 Controller 读取信息，但是当我添加 arduinoData.write(str.encode(ALL_DATA)) 时，它会降低很多速度，我该怎么办？

该行几乎添加到底部。是线的放置吗？它确实有效，但发送更新的速度不如我不写入串行。

import sys
import serial
import pygame
import time

from pygame.locals import *
pygame.init()

A0_value = '0'
A1_value = '0'
A2_value = '0'
A3_value = '0'
A4_value = '0'
A5_value = '0'
A6_value = '0'
B2 = '0'
B3 = '0'
B4 = '0'
B5 = '0'
global axis_data 

## 
arduinoData = serial.Serial('COM8',9600)

##

def main():
    global axis_data , button_data
    screen = pygame.display.set_mode((500, 700))
    pygame.display.set_caption("Joystick example")

    clock = pygame.time.Clock()
    joysticks = {}

    while True:
        for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    done = True  # Flag that we are done so we exit this loop.

                if event.type == pygame.JOYBUTTONDOWN:
                    print("Joystick button pressed.")
                    if event.button == 0:
                        joystick = joysticks[event.instance_id]
                        if joystick.rumble(0, 0.7, 500):
                            print(
                                "Rumble effect played on joystick {}".format(
                                    event.instance_id
                                )
                            )

                if event.type == pygame.JOYBUTTONUP:
                    print("Joystick button released.")

                # Handle hotplugging
                if event.type == pygame.JOYDEVICEADDED:
                    # This event will be generated when the program starts for every
                    # joystick, filling up the list without needing to create them manually.
                    joy = pygame.joystick.Joystick(event.device_index)
                    joysticks[joy.get_instance_id()] = joy
                    print("Joystick {} connencted".format(joy.get_instance_id()))

                if event.type == pygame.JOYDEVICEREMOVED:
                    del joysticks[event.instance_id]
                    print("Joystick {} disconnected".format(event.instance_id))




        for joystick in joysticks.values():
            axes = joystick.get_numaxes()
            #print("Number of axes: {}".format(axes))
            axis_str = [''] * axes
            button_data = ""
            axis_data = ""



            for i in range(axes):
                axis = joystick.get_axis(i)
                axis_int = int(axis*100)
                axis_str[i] = str(axis_int)
                axis_data = axis_str[i] + "," + axis_data 
                #print("Axis {} value: {}".format(i, axis)) 
            
            #print(axis_data)
            buttons = joystick.get_numbuttons()
            #print("Number of buttons: {}".format(buttons))
            button_str = ['0'] * buttons

            for i in range(buttons):
                button = joystick.get_button(i)
                button_str[i] = str(button)
                #print("Button {} value: {}".format(i, button))
                button_data = button_str[i] + "," + button_data
            
            #print(button_data)
            ALL_DATA = axis_data + button_data
            ALL_DATA = ALL_DATA[:-1] + "!"
            print(ALL_DATA)
        arduinoData.write(str.encode(ALL_DATA))

        
            
       # pygame.display.update()
        clock.tick(60)


if __name__ == "__main__":
    main()
    # If you forget this line, the program will 'hang'
    # on exit if running from IDLE.
    pygame.quit()

Answer 1

以 9600 波特写入串口真的很慢。引用 this answer在波特率发送时间上，发送每个字母的时间略多于 1 毫秒(大约)。请注意，在 60 FPS 下，每帧允许约 17 毫秒。代码将此数据作为字符串写入，因此每次循环可能需要相当多的毫秒数。

一个真正容易的胜利是简单地使用更快的波特率。您至少可以尝试 230400 以获得 24 倍的加速。

此外，我们几乎从不将实时数据作为字符串发送。您可以使用 Python struct module将所有各种操纵杆读数打包成二进制数据，这样会更加紧凑。特别是如果您将按钮状态视为单个位，并且不需要在操纵杆位置上使用高分辨率。

最后，您的代码可以使用线程来执行串行通信，并行写入主 PyGame 循环。这适用于“IO 绑定(bind)”操作。