版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/shukebeta008/article/details/79335279
接下来可以说是本教程的核心内容了，不可能在一篇文章中讲完，首先讲一个比较初级的程序。树莓派可以接收同一个局域网上电脑的连接，并且电脑键盘上发出的前后左右的控制信号通过网络发向树莓派后，树莓派再经过串口发向Arduino，对电机进行控制。
树莓派需要实现的程序分为两部分，一个是Socket服务器，另一个是串口写入的代码。涉及到多线程知识。
客户端程序作为Socket客户端连入树莓派，然后通过pygame库获取键盘命令后把运动指令发往树莓派。
树莓派的程序稍微复杂些，首先主循环是监听客户端连入，连入后用另一个线程对从客户端发来的数据进行处理，把指令用串口下发给Arduino。当指令涉及到超声波读取时，树莓派用另一个线程去监听串口收到的数据，这个数据就是距离数据（为了尽量简化，下面的代码范例中不含超声波读取部分，完整部分参见后面教程中的最终程序）。
下面贴上部分代码：
首先是运行于小车树莓派中的程序：
#!/usr/bin/env python
import socket
import sys
import threading
import random
import os
import time
import struct
import serial
#import cv
#import Image,StringIO
port_serial="/dev/ttyACM0"
sl = serial.Serial(port_serial,9600)
HOST = "0.0.0.0"
PORT = 9004
SOCK_ADDR = (HOST, PORT)
exit_now = 0
def exit_signal_handle(sig,stack_frame):
global exit_now
print "EXIT sig"
exit_now = 1
class serial_thread(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def run(self):
self.running = True
while self.running:
try:
data=sl.readline()
print data
except:
print sys.exc_info()
def stop(self):
self.running = False
def forward():
print "forward"
string="1"
sl.write(string)
def reverse():
print "reverse"
string="2"
sl.write(string)
def pivot_left():
print "left"
string="3"
sl.write(string)
def pivot_right():
print "right"
string="4"
sl.write(string)
def stop():
print "stop"
string="0"
sl.write(string)
def net_input(command):
global laser_index_vertical
global laser_index_horizontal
if command == 1:
forward()
elif command == 2:
reverse()
elif command == 3:
pivot_left()
elif command == 4:
pivot_right()
elif command == 0:
stop()
###
class SocketClientObject(object):
def __init__(self, socket, address ):
self.socket = socket
self.address = address
###
class ClientThread(threading.Thread):
def __init__(self, client_object):
threading.Thread.__init__(self)
self.client_object = client_object
def run(self):
self.running = True
while self.running:
data = self.client_object.socket.recv(1024)
print ">> Received data: ", data, " from: ", self.client_object.address
if(data=='0'):
net_input(0)
elif(data=='1'):
net_input(1)
elif(data=='2'):
net_input(2)
elif(data=='3'):
net_input(3)
elif(data=='4'):
net_input(4)
elif(data=='5'):
break
print "client_quit"
self.client_object.socket.close()
def stop(self):
self.running = False
###
def main():
ser_th = serial_thread()
ser_th.start()
try:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(SOCK_ADDR)
sock.listen(5)
while exit_now == 0:
# accept connections from outside
(clientsocket, address) = sock.accept()
print " Accept client: ", address
# now do something with the clientsocket
# in this case, we'll pretend this is a threaded server
ct = ClientThread(SocketClientObject(clientsocket, address))
ct.start()
except:
print "#! EXC: ", sys.exc_info()
#sock.close()
#ser_th.stop()
#ser_th.join()
print "THE END! Goodbye!"
###
if __name__ == "__main__":
main()
接下来是电脑控制端运行的程序：
#!/usr/bin/env python
import socket
import time
import pygame
import cv2.cv as cv
import Image, StringIO
import threading
import cv2
import numpy as np
def main():
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(('192.168.1.10',9004))
pygame.init()
W, H = 320, 240
screen = pygame.display.set_mode((W, H))
clock = pygame.time.Clock()
running = True
command_to_send=0
command_last=0
laser_control = False
while running:
command_last=command_to_send
for event in pygame.event.get():
if event.type == pygame.QUIT:
command_to_send=5
running = False
elif event.type == pygame.KEYUP:
command_to_send=0
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_UP:
command_to_send=1
elif event.key == pygame.K_DOWN:
command_to_send=2
elif event.key == pygame.K_LEFT:
command_to_send=3
elif event.key == pygame.K_RIGHT:
command_to_send=4
if(command_to_send!=command_last):
sock.send(str(command_to_send))
clock.tick(50)
sock.close()
if __name__ == '__main__':
main()最后是小车arduino中运行的代码（只包含控制部分，不含超声波）：
int led = 13;
void setup()
{
Serial.begin(9600);
pinMode(led, OUTPUT);
pinMode(9,OUTPUT);
pinMode(10,OUTPUT);
pinMode(5,OUTPUT);
pinMode(6,OUTPUT);
}
void loop()
{
//digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(100); // wait for a second
//digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
//delay(1000); // wait for a second
if (Serial.available()>0)
{
char cmd = Serial.read();
Serial.print(cmd);
switch (cmd)
{
case '1':
Serial.println("Forward");
Forward();
break;
case '2':
Serial.println("Back");
Back();
break;
case '3':
Serial.println("Left");
Turn_left();
break;
case '4':
Serial.println("Right");
Turn_right();
break;
default:
Stop();
}
}
}
void Forward()
{
digitalWrite(9,HIGH);
digitalWrite(10,LOW);
digitalWrite(5,HIGH);
digitalWrite(6,LOW);
}
void Back()
{
digitalWrite(9,LOW);
digitalWrite(10,HIGH);
digitalWrite(5,LOW);
digitalWrite(6,HIGH);
}
void Turn_right()
{
digitalWrite(9,LOW);
digitalWrite(10,HIGH);
digitalWrite(5,HIGH);
digitalWrite(6,LOW);
}
void Turn_left()
{
digitalWrite(9,HIGH);
digitalWrite(10,LOW);
digitalWrite(5,LOW);
digitalWrite(6,HIGH);
}
void Stop()
{
digitalWrite(9,LOW);
digitalWrite(10,LOW);
digitalWrite(5,LOW);
digitalWrite(6,LOW);
}