小车案例

案例简介

该案例是对前面内容的综合运用，所以不再做进一步的讲解！ 大家需要根据前面我们所学过的内容增强动手去把小车做出来！

为了降低大家的实现难度，我已经将要实现的大致步骤，以及示例代码给出！

材料清单

  1. 树莓派3B+
  2. 电源
  3. 电机
  4. L298N电机驱动板

连线

功能实现

通讯

前进

后退

左转

右转

下位机示例代码：

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#-*- coding:utf-8 -*-
import RPi.GPIO as GPIO
import socket
import time
import string
import threading


#小车状态值定义
enSTOP = 0
enRUN =1
enBACK = 2
enLEFT = 3
enRIGHT = 4
enTLEFT =5
enTRIGHT = 6


#小车电机引脚定义
IN1 = 20
IN2 = 21
IN3 = 19
IN4 = 26
ENA = 16
ENB = 13




#小车和舵机状态变量
g_CarState = 0

#小车速度变量
CarSpeedControl = 35

# 小车转向速度变量
CarDirectSpeedControl=80

#设置GPIO口为BCM编码方式
GPIO.setmode(GPIO.BCM)

#忽略警告信息
GPIO.setwarnings(False)

#电机引脚初始化为输出模式
def init():
    global pwm_ENA
    global pwm_ENB

    GPIO.setup(ENA,GPIO.OUT,initial=GPIO.HIGH)
    GPIO.setup(IN1,GPIO.OUT,initial=GPIO.LOW)
    GPIO.setup(IN2,GPIO.OUT,initial=GPIO.LOW)

    GPIO.setup(ENB,GPIO.OUT,initial=GPIO.HIGH)
    GPIO.setup(IN3,GPIO.OUT,initial=GPIO.LOW)
    GPIO.setup(IN4,GPIO.OUT,initial=GPIO.LOW)

    #设置pwm引脚和频率为2000hz
    pwm_ENA = GPIO.PWM(ENA, 2000)
    pwm_ENB = GPIO.PWM(ENB, 2000)
    pwm_ENA.start(0)
    pwm_ENB.start(0)


#小车前进   
def run():
    GPIO.output(IN1, GPIO.HIGH)
    GPIO.output(IN2, GPIO.LOW)

    GPIO.output(IN3, GPIO.LOW)
    GPIO.output(IN4, GPIO.LOW)
    pwm_ENA.ChangeDutyCycle(CarSpeedControl)
    pwm_ENB.ChangeDutyCycle(CarDirectSpeedControl)

#小车后退
def back():
    GPIO.output(IN1, GPIO.LOW)
    GPIO.output(IN2, GPIO.HIGH)

    GPIO.output(IN3, GPIO.LOW)
    GPIO.output(IN4, GPIO.LOW)
    pwm_ENA.ChangeDutyCycle(CarSpeedControl)
    pwm_ENB.ChangeDutyCycle(CarDirectSpeedControl)

#小车左转   
def left():
    GPIO.output(IN1, GPIO.LOW)
    GPIO.output(IN2, GPIO.LOW)

    GPIO.output(IN3, GPIO.HIGH)
    GPIO.output(IN4, GPIO.LOW)

    pwm_ENA.ChangeDutyCycle(CarSpeedControl)
    pwm_ENB.ChangeDutyCycle(CarDirectSpeedControl)

#小车右转
def right():
    GPIO.output(IN1, GPIO.LOW)
    GPIO.output(IN2, GPIO.LOW)

    GPIO.output(IN3, GPIO.LOW)
    GPIO.output(IN4, GPIO.HIGH)

    pwm_ENA.ChangeDutyCycle(CarSpeedControl)
    pwm_ENB.ChangeDutyCycle(CarDirectSpeedControl)

#小车原地左转
def spin_left():
    GPIO.output(IN1, GPIO.HIGH)
    GPIO.output(IN2, GPIO.LOW)

    GPIO.output(IN3, GPIO.HIGH)
    GPIO.output(IN4, GPIO.LOW)

    pwm_ENA.ChangeDutyCycle(CarSpeedControl)
    pwm_ENB.ChangeDutyCycle(CarSpeedControl)

#小车原地右转
def spin_right():
    GPIO.output(IN1, GPIO.LOW)
    GPIO.output(IN2, GPIO.LOW)

    GPIO.output(IN3, GPIO.LOW)
    GPIO.output(IN4, GPIO.HIGH)
    pwm_ENA.ChangeDutyCycle(CarSpeedControl)
    pwm_ENB.ChangeDutyCycle(CarSpeedControl)

#小车停止   
def brake():
   GPIO.output(IN1, GPIO.LOW)
   GPIO.output(IN2, GPIO.LOW)
   GPIO.output(IN3, GPIO.LOW)
   GPIO.output(IN4, GPIO.LOW)


try:
    init()

    global connectflag 
    connectflag = 0

    count = 50
    # 通过socket创建监听套接字并设置为非阻塞模式
    tcpservicesock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    tcpservicesock.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
    tcpservicesock.setblocking(0)
    # 填充绑定服务器的ip地址和端口号
    # 注意：这里一定要根据自己的树莓派的ip地址来填
    tcpservicesock.bind(('192.168.12.1', 8888))
    # 监听客户端的连接
    tcpservicesock.listen(5)
    print("waiting for connection....")
    # 创建监听列表
    clientAddrList = []

    print("服务器已经开启啦!")
    while True:
        try:
            #准备接受客户端的连接并返回连接套接字
            tcpclientsock,addr = tcpservicesock.accept()
            if  tcpclientsock:
                connectflag = 1
            print("连接成功啦!")
        except:
            pass 
        else:
            print("new user :%s " % str(addr))
            #设置连接套接字为非阻塞的模式并将连接的套接字放入到监听列表中
            tcpclientsock.setblocking(0)
            clientAddrList.append((tcpclientsock,addr))

        for tcpclientsock,addr in clientAddrList:
            try:
                global recvbuf
                global sendbuf
                recvbuf = ''
                #TCP接受数据
                # print("Start recv!",addr)
                recvbuf = tcpclientsock.recv(128)
                print("Start recv over!")
            except:
                pass
            else:
                if len(recvbuf) > 0:

                     print("recvbuf",recvbuf)
                     g_CarState = int(recvbuf);
                     # 根据解析的数据让小车做出相应的运动
                     if g_CarState == enSTOP:
                         brake()
                     elif g_CarState == enRUN:
                         run()
                     elif g_CarState == enLEFT:
                         print("左转")
                         left()
                     elif g_CarState == enRIGHT:
                         right()
                     elif g_CarState == enBACK:
                         back()
                     elif g_CarState == enTLEFT:
                         spin_left()
                     elif g_CarState == enTRIGHT:
                         spin_right()
                     else:
                         brake()

                else:
                    tcpclientsock.close()
                    clientAddrList.remove((tcpclientsock,addr))


except KeyboardInterrupt:
    pass
tcpclientsock.close()
tcpservicesock.close()
pwm_ENA.stop()
pwm_ENB.stop()

GPIO.cleanup()

上位机示例代码：

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"""
Created by Kaijun on 2019/8/2
  小车上位机程序
"""
from PyQt5.QtWidgets import QApplication,QWidget,QPushButton,QVBoxLayout,QHBoxLayout
import sys
from socket import *
import threading


address = "192.168.12.1"
port = 8888;
server_socket="";

def connectCar():
    global server_socket;
    server_socket = socket(AF_INET, SOCK_STREAM)
    server_socket.connect((address, port))
    print("连接成功!")


#小车状态值定义
enSTOP = 0
enRUN =1
enBACK = 2
enLEFT = 3
enRIGHT = 4
enTLEFT =5
enTRIGHT = 6


def controlCallback(val):
    print("发送数据",val)
    server_socket.send(str(val).encode())


if __name__ == '__main__':
    # 创建核心类
    app = QApplication(sys.argv)

    # 创建窗口
    widget = QWidget();
    widget.resize(200,400)

    # 创建水平布局
    vbox = QVBoxLayout(widget)

    leftBtn = QPushButton("连接");
    vbox.addWidget(leftBtn)
    leftBtn.clicked.connect(lambda : connectCar())

    # 创建按钮
    leftBtn = QPushButton("左转");
    vbox.addWidget(leftBtn)
    leftBtn.clicked.connect(lambda :controlCallback(enLEFT))
    # 创建按钮
    rightBtn = QPushButton("右转");
    vbox.addWidget(rightBtn)
    rightBtn.clicked.connect(lambda :controlCallback(enRIGHT))
    # 创建按钮
    forwordBtn = QPushButton("前进");
    vbox.addWidget(forwordBtn)
    forwordBtn.clicked.connect(lambda :controlCallback(enRUN))
    # 创建按钮
    backBtn = QPushButton("后退");
    vbox.addWidget(backBtn)
    backBtn.clicked.connect(lambda :controlCallback(enBACK))
    # 创建按钮
    stopBtn = QPushButton("停止");
    vbox.addWidget(stopBtn)
    stopBtn.clicked.connect(lambda :controlCallback(enSTOP))

    widget.show()
    app.exec()