愿君学长松，慎勿作桃李。这篇文章主要讲述开发板漂流计划 HarmonyOSAPP控制超声波小车相关的知识，希望能为你提供帮助。
【开发板漂流计划】 HarmonyOSAPP控制超声波小车 1.超声波小车介绍
①.本项目采用的开发套件为HiSpark Wi-Fi IoT智能小车 ②.项目预览

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视频链接：https://www.bilibili.com/video/BV1pS4y1Y72j/
代码开源地址：https://gitee.com/yukoyu/harmony-wifi-car
③.框架图
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④.HarmonyOS采用 java方式开发 2.小车端开发
①.新建文件夹路径：openharmony\\applications\\sample\\wifi-iot\\app\\

mkdir wificar

②.编写小车电机驱动

路径：openharmony\\applications\\sample\\wifi-iot\\app\\wificar\\robot_l9110s.c

代码：

#define GPIO0 0 #define GPIO1 1 #define GPIO9 9 #define GPIO10 10 #define GPIOFUNC 0 #define PWM_FREQ_FREQUENCY(60000)void gpio_control (unsigned intgpio, IotGpioValue value) hi_io_set_func(gpio, GPIOFUNC); IoTGpiosetDir(gpio, IOT_GPIO_DIR_OUT); IoTGpioSetOutputVal(gpio, value); //后退 void car_backward(void) gpio_control(GPIO0, IOT_GPIO_VALUE0); gpio_control(GPIO1, IOT_GPIO_VALUE1); gpio_control(GPIO9, IOT_GPIO_VALUE0); gpio_control(GPIO10, IOT_GPIO_VALUE1); //前进 void car_forward(void) gpio_control(GPIO0, IOT_GPIO_VALUE1); gpio_control(GPIO1, IOT_GPIO_VALUE0); gpio_control(GPIO9, IOT_GPIO_VALUE1); gpio_control(GPIO10, IOT_GPIO_VALUE0); //左转 void car_left(void) gpio_control(GPIO0, IOT_GPIO_VALUE0); gpio_control(GPIO1, IOT_GPIO_VALUE0); gpio_control(GPIO9, IOT_GPIO_VALUE1); gpio_control(GPIO10, IOT_GPIO_VALUE0); //右转 void car_right(void) gpio_control(GPIO0, IOT_GPIO_VALUE1); gpio_control(GPIO1, IOT_GPIO_VALUE0); gpio_control(GPIO9, IOT_GPIO_VALUE0); gpio_control(GPIO10, IOT_GPIO_VALUE0); //停止转动 void car_stop(void) gpio_control(GPIO0, IOT_GPIO_VALUE1); gpio_control(GPIO1, IOT_GPIO_VALUE1); gpio_control(GPIO9, IOT_GPIO_VALUE1); gpio_control(GPIO10, IOT_GPIO_VALUE1);

③.编写舵机驱动

路径：openharmony\\applications\\sample\\wifi-iot\\app\\wificar\\robot_sg90.c

代码：

#define GPIO2 2 void set_angle( unsigned int duty) IoTGpioInit(GPIO2); IoTGpioSetDir(GPIO2, IOT_GPIO_DIR_OUT); IoTGpioSetOutputVal(GPIO2, IOT_GPIO_VALUE1); hi_udelay(duty); IoTGpioSetOutputVal(GPIO2, IOT_GPIO_VALUE0); hi_udelay(20000 - duty); //控制电机转动角度参数范围 1000< time< 2000 void custom(int time)for (int i = 0; i < 10; i++) set_angle(time);

④.编写超声波驱动

路径：openharmony\\applications\\sample\\wifi-iot\\app\\wificar\\robot_hcsr04.c

代码：

#define GPIO_8 8 #define GPIO_7 7 #define GPIO_FUNC 0 extern int cmm; void GetDistance(float *distance) static unsigned long start_time = 0, time = 0; IotGpioValue value = https://www.songbingjia.com/android/IOT_GPIO_VALUE0; unsigned int flag = 0; IoTWatchDogDisable(); hi_io_set_func(GPIO_8, GPIO_FUNC); IoTGpioSetDir(GPIO_8, IOT_GPIO_DIR_IN); IoTGpioSetDir(GPIO_7, IOT_GPIO_DIR_OUT); IoTGpioSetOutputVal(GPIO_7, IOT_GPIO_VALUE1); hi_udelay(20); IoTGpioSetOutputVal(GPIO_7, IOT_GPIO_VALUE0); while (1) IoTGpioGetInputVal(GPIO_8, & value); if ( value == IOT_GPIO_VALUE1 & & flag == 0) start_time = hi_get_us(); flag = 1; if (value == IOT_GPIO_VALUE0 & & flag == 1) time = hi_get_us() - start_time; start_time = 0; break; *distance = time * 0.034 / 2; printf("distance is %f\\r\\n",*distance); return ;

⑤.编写wifi和socket server

路径：openharmony\\applications\\sample\\wifi-iot\\app\\wificar\\wifi_sockets.c

代码：

// 接收、发送的数据 static char request[256] = ""; // 未连接热点=0，已连接热点=1 static int g_connected = 0; int connfd = -1; // 输出连接信息字符串 // 打印内容样例--> bssid: 38:47:BC:49:01:FA, rssi: 0, connState: 0, reason: 0, ssid: MyMobile void PrintLinkedInfo(WifiLinkedInfo* info) if (!info) return; static char macAddress[32] = 0; unsigned char* mac = info-> bssid; snprintf(macAddress, sizeof(macAddress), "%02X:%02X:%02X:%02X:%02X:%02X", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]); printf("bssid: %s, rssi: %d, connState: %d, reason: %d, ssid: %srn", macAddress, info-> rssi, info-> connState, info-> disconnectedReason, info-> ssid); // 连接状态改变事件处理 void OnWifiConnectionChanged(int state, WifiLinkedInfo* info) if (!info) return; // 输出类似内容：OnWifiConnectionChanged 31, state = 1, info = printf("%s %d, state = %d, info = rn", __FUNCTION__, __LINE__, state); PrintLinkedInfo(info); // 根据连接状态设置g_connected if (state == WIFI_STATE_AVALIABLE) g_connected = 1; else g_connected = 0; // 扫描状态改变事件处理 void OnWifiScanStateChanged(int state, int size) printf("%s %d, state = %X, size = %drn", __FUNCTION__, __LINE__, state, size); void DisconnectTcpSocket(int connfd) sleep(1); printf("do_disconnect...rn"); lwip_close(connfd); sleep(1); // for debugvoid CloseTcpSocket(int socketfd) printf("do_cleanup...rn"); lwip_close(socketfd); static void TcpServerHandler(void) ssize_t retval = 0; unsigned short port = 20222; // 创建一个通信的Socket，并返回一个Socket文件描述符。第一个参数IpV4，第二个参数SOCK_STREAM类型，第三个指用到的协议 int sockfd = socket(AF_INET, SOCK_STREAM, 0); // 客户端地址和地址长度 struct sockaddr_in clientAddr = 0; socklen_t clientAddrLen = sizeof(clientAddr); // 服务端地址 struct sockaddr_in serverAddr = 0; serverAddr.sin_family = AF_INET; // htons是将整型变量从主机字节顺序转变成网络字节顺序，就是整数在地址空间存储方式变为高位字节存放在内存的低地址处 serverAddr.sin_port = htons(port); // 监听本机的所有IP地址，INADDR_ANY=0x0 // 将主机数转换成无符号长整型的网络字节顺序 serverAddr.sin_addr.s_addr = htonl(INADDR_ANY); // 服务端绑定端口 retval = bind(sockfd, (struct sockaddr *)& serverAddr, sizeof(serverAddr)); if (retval < 0) printf("bind failed, %ld!rn", retval); CloseTcpSocket(sockfd); return; printf("bind to port %d success!rn", port); // 开始监听，backlog指Pending连接队列增长到的最大长度。队列满了，再有新连接请求到达，则客户端ECONNREFUSED错误。如果支持重传，则请求忽略。 int backlog = 1; retval = listen(sockfd, backlog); if (retval < 0) printf("listen failed!rn"); CloseTcpSocket(sockfd); return; printf("listen with %d backlog success!rn", backlog); int outerFlag = 1; while (outerFlag) // 接受客户端连接，成功会返回一个表示连接的 socket。clientAddr参数将会携带客户端主机和端口信息；失败返回 -1 // 从Pending连接队列中获取第一个连接，根据sockfd的socket协议、地址族等内容创建一个新的socket文件描述，并返回。 // 此后的 收、发 都在 表示连接的 socket 上进行；之后 sockfd 依然可以继续接受其他客户端的连接， // UNIX系统上经典的并发模型是“每个连接一个进程”——创建子进程处理连接，父进程继续接受其他客户端的连接 // 鸿蒙liteos-a内核之上，可以使用UNIX的“每个连接一个进程”的并发模型liteos-m内核之上，可以使用“每个连接一个线程”的并发模型 connfd = accept(sockfd, (struct sockaddr *)& clientAddr, & clientAddrLen); if (connfd < 0) printf("accept failed, %d, %drn", connfd, errno); CloseTcpSocket(sockfd); //outerFlag = 0; printf("accept success, connfd = %d !rn", connfd); // inet_ntoa：网络地址转换成“.”点隔的字符串格式。ntohs：16位数由网络字节顺序转换为主机字节顺序。 printf("client addr info: host = %s, port = %drn", inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port)); int innerFlag = 1; // 接收消息，然后发送回去 while (innerFlag) // 后续 收、发 都在 表示连接的 socket 上进行； // 在新的Socket文件描述上接收信息. retval = recv(connfd, request, sizeof(request), 0); if (retval < 0) printf("recv request failed, %ld!rn", retval); innerFlag = 0; else if (retval == 0) // 对方主动断开连接 printf("client disconnected!rn"); innerFlag = 0; else //printf("recv request%s from client done!rn", request); // 发送数据 printf("cc = %d %d %d \\r\\n",request[0],request[1],request[2]); if (retval < = 0) printf("send response failed, %ld!rn", retval); innerFlag = 0; if(retval == 3 & & request[0] == -86)if(request[1] = 0x00) retval = send(connfd, "aaok", strlen("aaok"), 0); if(request[1] = 0x01)switch (request[2])case 1: car_forward(); break; case 2: car_right(); break; case 3: car_backward(); break; case 4: car_left(); break; case 0: car_stop(); break; //printf("send response%s to client done!rn", request); // 清空缓冲区 memset(& request, 0, sizeof(request)); if(innerFlag == 0)DisconnectTcpSocket(connfd); //outerFlag = 0; CloseTcpSocket(sockfd); void *TcpServerTask(void *arg) (void)arg; // 先定义两个Wifi监听器，一个连接改变、一个状态改变 WifiEvent eventListener = .OnWifiConnectionChanged = OnWifiConnectionChanged, .OnWifiScanStateChanged = OnWifiScanStateChanged ; // 等待10个系统Ticks。每个ticks多少个us，计算方式= 1000 * 1000 / osKernelGetTickFreq() osDelay(10); // 注册监听器 WifiErrorCode errCode = RegisterWifiEvent(& eventListener); printf("RegisterWifiEvent: %drn", errCode); // 设置Wifi热点信息 WifiDeviceConfig apConfig = ; strcpy(apConfig.ssid, "PDCN"); strcpy(apConfig.preSharedKey, "1234567888"); apConfig.securityType = WIFI_SEC_TYPE_PSK; int netId = -1; // 启用Wifi errCode = EnableWifi(); printf("EnableWifi: %drn", errCode); osDelay(10); // 设置Wifi热点配置信息，返回生成的网络Id-netId。 errCode = AddDeviceConfig(& apConfig, & netId); printf("AddDeviceConfig: %drn", errCode); // 根据网络Id连接到Wifi热点 g_connected = 0; errCode = ConnectTo(netId); printf("ConnectTo(%d): %drn", netId, errCode); // 未连接完成，则一直等待。g_connected状态会在事件中设置。 while (!g_connected) osDelay(10); printf("g_connected: %drn", g_connected); osDelay(50); // 联网业务开始，找到netifname=wlan0的netif。 struct netif* iface = netifapi_netif_find("wlan0"); if (iface) // 启动DHCP客户端，获取IP地址 err_t ret = netifapi_dhcp_start(iface); printf("netifapi_dhcp_start: %drn", ret); // 等待DHCP服务器反馈给予地址 osDelay(300); // 执行线程安全的网络方法，第二个参数是voidFunc，第三个参数是errFunc。如果没有errFunc，那么就执行voidFunc。 // netifapi_dhcp_start/netifapi_dhcp_stop等都是调用的netifapi_netif_common方法。 // dhcp_clients_info_show显示信息 /* server : server_id : 192.168.0.1 mask : 255.255.255.0, 1 gw : 192.168.0.1 T0 : 3600 T1 : 1800 T2 : 3150 clients < 1> : mac_idx macaddrstateleasetriesrto 0b4c9b9af69f8192.168.0.1010012 */ ret = netifapi_netif_common(iface, dhcp_clients_info_show, NULL); printf("netifapi_netif_common: %drn", ret); TcpServerHandler(); // 联网业务结束，断开DHCP err_t ret = netifapi_dhcp_stop(iface); printf("netifapi_dhcp_stop: %drn", ret); // 断开Wifi热点连接 Disconnect(); // 移除Wifi热点的配置 RemoveDevice(netId); // 关闭Wifi errCode = DisableWifi(); printf("DisableWifi: %drn", errCode); osDelay(200); void WifiSockets(void)osThreadAttr_t wifisocket; wifisocket.name = "TcpServerTask"; wifisocket.attr_bits = 0U; wifisocket.cb_mem = NULL; wifisocket.cb_size = 0U; wifisocket.stack_mem = NULL; wifisocket.stack_size = 10240; wifisocket.priority = 25; if (osThreadNew(TcpServerTask, NULL, & wifisocket) == NULL) printf("[Ssd1306TestDemo] Falied to create TcpServerTask!\\n"); APP_FEATURE_INIT(WifiSockets);

⑥.编写主控制代码

路径：openharmony\\applications\\sample\\wifi-iot\\app\\wificar\\robot_control.c

代码：

static char data[128] = ""; extern int connfd; void *RobotCarTestTask(void* param)(void)param; float cmm = 0.0; printf("switch\\r\\n"); int i= 0; int flag = 0; while (1) custom((i%11)*100 + 1000); GetDistance(& cmm); sprintf(data,"\\"angle\\": %d,\\"cm\\":%f",i,cmm); send(connfd, data, strlen(data), 0); //发送距离到APP //printf("\\r\\n cos = %dcm =%f\\r\\n",i,cmm); if(flag == 0)i++; if(i%10 == 0)flag = 1; else i--; if(i%11 == 0)flag = 0; osDelay(25); //延时 250msvoid RobotCarDemo(void)osThreadAttr_t attr; attr.name = "RobotCarTestTask"; attr.attr_bits = 0U; attr.cb_mem = NULL; attr.cb_size = 0U; attr.stack_mem = NULL; attr.stack_size = 10240; attr.priority = 25; if (osThreadNew(RobotCarTestTask, NULL, & attr) == NULL) printf("[Ssd1306TestDemo] Falied to create RobotCarTestTask!\\n"); APP_FEATURE_INIT(RobotCarDemo);

⑦.编写编译描述文件路径：openharmony\\applications\\sample\\wifi-iot\\app\\wificar\\BUILD.gn
代码：

static_library("car_wifi") sources = [ "robot_l9110s.c", "robot_sg90.c", "robot_control.c", "robot_hcsr04.c", "wifi_sockets.c", ] deps =[ ] include_dirs = [ "//utils/native/lite/include", "//kernel/liteos_m/kal/cmsis", "//base/iot_hardware/peripheral/interfaces/kits", "//device/hisilicon/hispark_pegasus/hi3861_adapter/hals/communication/wifi_lite/wifiservice", "//device/hisilicon/hispark_pegasus/hi3861_adapter/kal", "//device/hisilicon/hispark_pegasus/sdk_liteos/third_party/lwip_sack/include", "//foundation/communication/wifi_lite/interfaces/wifiservice" ]

⑧.加入编译路径：openharmony\\applications\\sample\\wifi-iot\\app\\BUILD.gn
代码：

import("//build/lite/config/component/lite_component.gni")lite_component("app") features = [ "wificar:car_wifi" ]

⑨.编译 1）.设置编译路径

hb set .(英文字符)

2）.选择wifiiot_hispark_pegasus 3）.执行编译

hb build -f

4）.输出路径

openharmony\\out\\hispark_pegasus\\wifiiot_hispark_pegasus

⑩.烧录
参考烧录：https://ost.51cto.com/posts/11118
4.HarmonyOS 端开发
①.新建项目 打开 DevEco Studio 3.0.0.800 选择File -> New -> New Project 选择
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选择
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点击Finish ②.应用签名 1）.复制bundleName
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2).打开链接https://developer.huawei.com/consumer/cn/service/josp/agc/index.html#/myProject
3).点击添加项目
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4）.输入项目名
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5）.点击添加应用
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6）.如图设置
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7）.点击
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8）.登录
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9）.获取签名（未连接手机）
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9）.获取签名（连接手机），点击Try Again，获取成功
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③.导入gson包

implementation com.google.code.gson:gson:2.8.9

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④.打开网络权限

"reqPermissions": [ "name":"ohos.permission.GET_NETWORK_INFO", "name":"ohos.permission.SET_NETWORK_INFO", "name":"ohos.permission.INTERNET" ],

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⑤.UI设置这里对UI就不展开讲了

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⑥.编写代码
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编写文件：Elements.java代码：

package com.example.wificardemo.slice; public class Elements int angle = 0; float cm = 0;

编写文件：MainAbilitySlice.java代码：

package com.example.wificardemo.slice; import com.example.wificardemo.ResourceTable; import ohos.aafwk.ability.AbilitySlice; import ohos.aafwk.content.Intent; import ohos.agp.components.Button; import ohos.agp.components.Component; import ohos.agp.components.ProgressBar; import ohos.agp.components.TextField; import ohos.global.resource.Resource; import ohos.hiviewdfx.HiLog; import ohos.hiviewdfx.HiLogLabel; import java.util.List; public class MainAbilitySlice extends AbilitySlice private static final HiLogLabel hilog = new HiLogLabel(HiLog.DEBUG ,0x0000, "test0002"); SocketTest ST = null; ProgressBar[] PB = new ProgressBar[11]; @Override public void onStart(Intent intent) int pbs[] = ResourceTable.Id_progressbar,ResourceTable.Id_progressbar1,ResourceTable.Id_progressbar2,ResourceTable.Id_progressbar3,ResourceTable.Id_progressbar4,ResourceTable.Id_progressbar5,ResourceTable.Id_progressbar6,ResourceTable.Id_progressbar7,ResourceTable.Id_progressbar8,ResourceTable.Id_progressbar9,ResourceTable.Id_progressbar10; super.onStart(intent); super.setUIContent(ResourceTable.Layout_ability_main); Button connects = findComponentById(ResourceTable.Id_connect_car); Button bt1 = findComponentById(ResourceTable.Id_button1); Button bt2 = findComponentById(ResourceTable.Id_button2); Button bt3 = findComponentById(ResourceTable.Id_button3); Button bt4 = findComponentById(ResourceTable.Id_button4); Button bt5 = findComponentById(ResourceTable.Id_button5); TextField text_field = findComponentById(ResourceTable.Id_text_field); for(int i = 0; i< 11; i++)PB[i] = (ProgressBar)findComponentById(pbs[i]); bt1.setClickedListener(new Component.ClickedListener() @Override public void onClick(Component component) ST.sockerSend(1,1); ); bt2.setClickedListener(new Component.ClickedListener() @Override public void onClick(Component component) ST.sockerSend(1,4); ); bt3.setClickedListener(new Component.ClickedListener() @Override public void onClick(Component component) ST.sockerSend(1,0); ); bt4.setClickedListener(new Component.ClickedListener() @Override public void onClick(Component component) ST.sockerSend(1,2); ); bt5.setClickedListener(new Component.ClickedListener() @Override public void onClick(Component component) ST.sockerSend(1,3); ); connects.setClickedListener(new Component.ClickedListener() @Override public void onClick(Component component) if(ST !=null)ST = null; //释放try ST = new SocketTest(MainAbilitySlice.this,text_field.getText().toString(),20222); ST.start(); Thread.sleep(200); //ST.sockerSend(5,0,0); catch (Exception e) e.printStackTrace(); ); //Socker 接收回调函数 public void socketCallback(Elements con) getUITaskDispatcher().asyncDispatch(new Runnable() @Override public void run() PB[con.angle].setProgressValue(con.cm> 100 ? 100:(int)con.cm); ); @Override public void onActive() super.onActive(); @Override public void onForeground(Intent intent) super.onForeground(intent);

编写文件：SocketTest.java代码：

package com.example.wificardemo.slice; import com.google.gson.Gson; import ohos.hiviewdfx.HiLog; import ohos.hiviewdfx.HiLogLabel; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.Socket; public class SocketTest extends Thread private static final HiLogLabel hilog = new HiLogLabel(HiLog.DEBUG ,0x0000, "test0002"); Socket socket = null; String host =""; int port = 0; InputStream inputStream = null; OutputStream outputStream=null; public boolean flag; MainAbilitySlice mains = null; public SocketTest(MainAbilitySlice mains,String host,int port) this.mains = mains; this.host = host; this.port = port; public void sockerSend(int a,int b) if(socket != null & & outputStream != null)new Thread(new Runnable() @Override public void run() try byte[] data =https://www.songbingjia.com/android/new byte[3]; data[0] = (byte) 0xaa; data[1] = (byte) a; data[2] = (byte) b; //data[3] = (byte) c; outputStream.write(data); outputStream.flush(); catch (IOException e) e.printStackTrace(); ).start(); else@Override public void run() try flag = true; while (flag)socket = new Socket(host, port); outputStream = socket.getOutputStream(); inputStream =socket.getInputStream(); init1(); socket.close(); catch (IOException e) System.out.println("net erorr!"+e); public void init1() try byte[] b = new byte[1024]; while (flag)int n = inputStream.read(b); if(n !=-1)byte[] data = https://www.songbingjia.com/android/new byte[n]; for (int i=0; i< n; i++)data[i] = b[i]; String str = new String(data); Gson gson = new Gson(); HiLog.debug(hilog,"net !"+str,""); if(n > 10) mains.socketCallback(gson.fromJson(str, Elements.class)); else break; catch (Exception e) HiLog.debug(hilog,"net erorr!"+e,"");

⑦.点击RUN 安装到手机 5.测试

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【开发板漂流计划 HarmonyOSAPP控制超声波小车】
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视频链接：https://www.bilibili.com/video/BV1pS4y1Y72j/
代码开源地址：https://gitee.com/yukoyu/harmony-wifi-car
测试成功！附件链接：https://ost.51cto.com/resource/1864
想了解更多关于鸿蒙的内容，请访问：
51CTO OpenHarmony技术社区
https://ost.51cto.com/#bkwz
::: hljs-center

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:::

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