FPVcar

发表于

项目概况

使用的是上一个项目Ball Tracer的底盘，硬件方面基本没变。这次主要是想尝试一下用python实现socket通信。

Socket简介

Socket又称”套接字”，应用程序通常通过”套接字”向网络发出请求或者应答网络请求，使主机间或者一台计算机上的进程间可以通讯。Socket是应用层与传输层间的一个抽象层，是个编程接口。

拓展阅读：计算机网络层级

在协议组学到的一些东西。

架构

网络

电脑和树莓派连接同一个路由器，处于一个局域网内。使用ifconfig/ipconfig查看ip地址，便于后续连接的建立。

socket

使用了两个socket,socket0负责传输图像，socket1负责传输操控指令。socket0从树莓派发往PC，socket1从PC发往树莓派。都是PC做服务器，树莓派做客户端。使用的是udp传输协议，延迟更低，丢包对视频传输的影响也不大。

操控

使用键盘操控，w前进，s后退，a左转，d右转。

代码

PC端

camera.py

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import cv2
import numpy
import socket
import struct
HOST='192.168.1.101'
PORT=9999
buffSize=65535

server=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
server.bind((HOST,PORT))

print('now waiting for frames')
while True:
    data,address=server.recvfrom(buffSize)
    if len(data)==1 and data[0]==1:
        server.close()
        cv2.destroyAllWindows()
        exit()
    try:
        data=bytearray(data)
        print('have recevied one frame',address)
        data=numpy.array(data)
        imgdecode=cv2.imdecode(data,1)
        cv2.imshow('frames',imgdecode)
        keycode=cv2.waitKey(10)&0xff
        if keycode==ord('q'):
            break
    except:
        continue
server.close()
cv2.destroyAllWindows()

control.py

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import cv2
import socket
HOST='192.168.1.101'
PORT=8888
buffSize=65535

server=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
server.bind((HOST,PORT))

print('now waiting for connection')

background=cv2.imread('background.jpg')

while True:
    data,address=server.recvfrom(buffSize)
    if len(data)==1 and data[0]==1:
        server.close()
        exit()
    if data==b'hello':
        print('start',address)
        
        while True:
            cv2.imshow('background',background)
            c=cv2.waitKey(100)&0xff
            if c==ord('q'):
                server.close()
                exit()
            c=chr(c)
            server.sendto(c.encode('utf-8'),address)
    try:
        
        print('have recevied one msg:',data,address)
        
    except:
        continue
server.close()
exit()

树莓派

camera.py

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buffSize=65535
server=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)

cap = cv2.VideoCapture(0)
while True:
	ret, frame= cap.read()
	frame=cv2.flip(frame,-1,dst=None)
	if ret is False:
		print 'f'
		continue
	cv2.imshow('the frame',frame)
	keycode=cv2.waitKey(10)&0xff
	if keycode==ord('q'):
		break
	
	ret,imgencode=cv2.imencode('.jpg',frame,[cv2.IMWRITE_JPEG_QUALITY,50])
	server.sendto(imgencode,(HOST,PORT))

control.py

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import socket
import time
import RPi.GPIO as GPIO
import gpiotest as gp

GPIO.setmode(GPIO.BOARD)
INT1=11 
INT2=12
INT3=13
INT4=15

GPIO.setup(INT1,GPIO.OUT)
GPIO.setup(INT2,GPIO.OUT)
GPIO.setup(INT3,GPIO.OUT)
GPIO.setup(INT4,GPIO.OUT)

HOST='192.168.1.101'
PORT=8888
buffSize=65535
server=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)

server.sendto('hello',(HOST,PORT))
while True:
	c,addr=server.recvfrom(buffSize)
	c=c.decode('utf-8')
	c=c.encode('ascii','ignore')
	print(c,type(c))

	
	if c=='w':
		gp.f(0.05)
		print('w'*100)
	elif c==u's':
		gp.b(0.05)
	elif c==u'a':
		gp.t_l(0.05)
	elif c==u'd':
		gp.t_r(0.05)
	elif c==u'q':
		server.close()
		exit()

gpiotest.py

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import cv2
import RPi.GPIO as GPIO
import time
import random

GPIO.setmode(GPIO.BOARD)

INT1=11 
INT2=12
INT3=13
INT4=15

GPIO.setup(INT1,GPIO.OUT)
GPIO.setup(INT2,GPIO.OUT)
GPIO.setup(INT3,GPIO.OUT)
GPIO.setup(INT4,GPIO.OUT)

def b(time_):
    GPIO.output(INT2,GPIO.HIGH)
    GPIO.output(INT1,GPIO.LOW)
    GPIO.output(INT3,GPIO.HIGH)
    GPIO.output(INT4,GPIO.LOW)
    time.sleep(time_)
    GPIO.output(INT1,GPIO.LOW)
    GPIO.output(INT2,GPIO.LOW)
    GPIO.output(INT3,GPIO.LOW)
    GPIO.output(INT4,GPIO.LOW)

def f(time_):
    GPIO.output(INT2,GPIO.LOW)
    GPIO.output(INT1,GPIO.HIGH)
    GPIO.output(INT3,GPIO.LOW)
    GPIO.output(INT4,GPIO.HIGH)
    time.sleep(time_)
    GPIO.output(INT1,GPIO.LOW)
    GPIO.output(INT2,GPIO.LOW)
    GPIO.output(INT3,GPIO.LOW)
    GPIO.output(INT4,GPIO.LOW)

def t_l(time_):
    GPIO.output(INT2,GPIO.HIGH)
    GPIO.output(INT1,GPIO.LOW)
    GPIO.output(INT3,GPIO.LOW)
    GPIO.output(INT4,GPIO.HIGH)
    time.sleep(time_)
    GPIO.output(INT1,GPIO.LOW)
    GPIO.output(INT2,GPIO.LOW)
    GPIO.output(INT3,GPIO.LOW)
    GPIO.output(INT4,GPIO.LOW)
    
def t_r(time_):
    GPIO.output(INT2,GPIO.LOW)
    GPIO.output(INT1,GPIO.HIGH)
    GPIO.output(INT3,GPIO.HIGH)
    GPIO.output(INT4,GPIO.LOW)
    time.sleep(time_)
    GPIO.output(INT1,GPIO.LOW)
    GPIO.output(INT2,GPIO.LOW)
    GPIO.output(INT3,GPIO.LOW)
    GPIO.output(INT4,GPIO.LOW)