一、硬件組成

1. esp32用作主控。（型號為：esp32_devkitc_v4）
2. 一塊串口屏用作顯示。(型號為：TJC3224T024_011)
3. Usb轉(zhuǎn)ttl模塊用作調(diào)試。

二、開發(fā)環(huán)境搭建（Arduino IDE）

1. 進(jìn)入Arduino官網(wǎng) https://www.arduino.cc/en/software下載Arduino IDE。安裝好后界面如下：
2. 搭建esp32開發(fā)環(huán)境：點(diǎn)擊文件/首選項(xiàng):

????????

輸入：https://dl.espressif.com/dl/package_esp32_index.json 保存并重啟Arduino

?選擇工具/開發(fā)板管理器

搜索esp32并下載安裝

完成后可以看到esp32

三、向api接口發(fā)送HTTP請求并解析

????????

1、在Arduino中安裝所需要的庫文件:點(diǎn)擊工具/管理庫?

????????在搜索框輸入 WiFi ，選中需要安裝的庫文件?

? ? ?????????

?2、設(shè)備初始化代碼

#include          //用于連接WiFi網(wǎng)絡(luò)#include    //用于向服務(wù)端請求數(shù)據(jù)信息#include   //用于解析返回的json數(shù)據(jù)const char *dssid = "ssid";    //你的網(wǎng)絡(luò)名稱const char *password = "password"; //你的網(wǎng)絡(luò)密碼void setup() {            //做設(shè)備初始化  Serial.begin(115200);   //初始化串口波特率為115200  Serial.println("");    //打印空白行  WiFi.begin(dssid,password);//連接指定wifi  while (WiFi.status() != WL_CONNECTED)  {    delay(500);    Serial.print(".");  }                    //連接中返回.....  Serial.println("WiFi connected!");//WiFi連接成功    // put your setup code here, to run once:}

3、請求數(shù)據(jù)并返回

void loop() {  HTTPClient http;     //建立HTTPClient對象  http.begin("https://lab.isaaclin.cn/nCoV/api/overall");//向該網(wǎng)址發(fā)送http數(shù)據(jù)請求  int httpCode = http.GET();     //保存返回的狀態(tài)碼  // put your main code here, to run repeatedly:  if (httpCode > 0) // 如果狀態(tài)碼大于0說明請求過程無異常  {    if (httpCode == HTTP_CODE_OK) // 請求被服務(wù)器正常響應(yīng)，等同于httpCode == 200    {      String payload = http.getString(); // 讀取服務(wù)器返回的響應(yīng)正文數(shù)據(jù)      Serial.println(payload);           //串口打印返回的數(shù)據(jù)    }  }  else  { //未被響應(yīng)返回錯誤碼    Serial.printf("[HTTP] GET... failed, error: %s/n",                 http.errorToString(httpCode).c_str());  }  http.end(); // 結(jié)束當(dāng)前連接  delay(1200000);//兩分鐘發(fā)送一次請求，過于頻繁可能導(dǎo)致ip被接口封掉}

4、下載驗(yàn)證：開發(fā)板型號選擇：

PS：端口根據(jù)自身情況選擇

串口打印結(jié)果如下：

?

返回?cái)?shù)據(jù)為：

5、對返回?cái)?shù)據(jù)做json解析：?定義結(jié)構(gòu)體

struct ncov_data{         //該結(jié)構(gòu)體用于保存數(shù)據(jù)    long currentConfirmedCount;//現(xiàn)存確診    long currentConfirmedIncr;//較昨日    long confirmedCount;//累計(jì)確診    long confirmedIncr;//較昨日    long curedCount;//累計(jì)治愈    long curedIncr;//較昨日    long seriousCount;//現(xiàn)存無癥狀    long seriousIncr;//較昨日    long deadCount;//累計(jì)死亡    long deadIncr;//較昨日    String updateTime;//更新時間};

Json初始化

ncov_data China_data;              //國內(nèi)疫情數(shù)據(jù)ncov_data World_data;              //國外疫情數(shù)據(jù)DynamicJsonDocument doc(1000);     //創(chuàng)建DynamicJsonDocument對象deserializeJson(doc, payload);     //反序列化數(shù)據(jù)JsonObject results_0 = doc["results"][0];

解析出的數(shù)據(jù)賦值

      China_data.currentConfirmedCount = results_0["currentConfirmedCount"].as();      China_data.currentConfirmedIncr = results_0["currentConfirmedIncr"].as();      China_data.confirmedCount = results_0["confirmedCount"].as();      China_data.confirmedIncr = results_0["confirmedIncr"].as();      China_data.curedCount = results_0["curedCount"].as();      China_data.curedIncr = results_0["curedIncr"].as();      China_data.deadCount = results_0["deadCount"].as();      China_data.deadIncr = results_0["deadIncr"].as();      China_data.seriousCount = results_0["seriousCount"].as();      China_data.seriousIncr = results_0["seriousIncr"].as();      World_data.currentConfirmedCount = results_0["globalStatistics"]["currentConfirmedCount"].as();      World_data.currentConfirmedIncr = results_0["globalStatistics"]["currentConfirmedIncr"].as();      World_data.confirmedCount = results_0["globalStatistics"]["confirmedCount"].as();      World_data.confirmedIncr = results_0["globalStatistics"]["confirmedIncr"].as();      World_data.curedCount = results_0["globalStatistics"]["curedCount"].as();      World_data.curedIncr = results_0["globalStatistics"]["curedIncr"].as();      World_data.deadCount = results_0["globalStatistics"]["deadCount"].as();      World_data.deadIncr = results_0["globalStatistics"]["deadIncr"].as();

串口打印

      Serial.println("");      Serial.println("----------------國內(nèi)疫情---------------");      Serial.print("現(xiàn)存確診: ");Serial.println(China_data.currentConfirmedCount);      Serial.print("累計(jì)確診: ");Serial.println(China_data.confirmedCount);      Serial.print("累計(jì)治愈: ");Serial.println(China_data.curedCount);      Serial.print("現(xiàn)存無癥: ");Serial.println(China_data.seriousCount);      Serial.print("累計(jì)死亡: ");Serial.println(China_data.deadCount);      Serial.println("----------------國外疫情---------------");      Serial.print("現(xiàn)存確診: ");Serial.println(World_data.currentConfirmedCount);      Serial.print("累計(jì)確診: ");Serial.println(World_data.confirmedCount);      Serial.print("累計(jì)治愈: ");Serial.println(World_data.curedCount);      Serial.print("累計(jì)死亡: ");Serial.println(World_data.deadCount);

四、發(fā)送數(shù)據(jù)到串口屏并顯示

????????1、下載USART HMI串口屏軟件，搭建自己喜歡的ui，過程可自行百度，略過。

? ? ? ? 2、Arduino代碼：串口定義

#define TJC Serial2       //串口屏收發(fā)串口定義為串口2

????????初始化

TJC.begin(115200);      //初始化收發(fā)串口波特率為115200while (TJC.read() >= 0);//等待串口屏連接成功

字符串定義

      char str1[20];      char str2[20];      char str3[20];      char str4[20];      char str5[20];      char str6[20];      char str7[20];      char str8[20];      char str9[20];      char str10[20];

sprintf格式拼接

      sprintf(str1, "n0.val=%d/xff/xff/xff", China_data.currentConfirmedCount);      sprintf(str6, "n5.val=%d/xff/xff/xff", China_data.currentConfirmedIncr);      sprintf(str2, "n1.val=%d/xff/xff/xff", China_data.confirmedCount);      sprintf(str7, "n6.val=%d/xff/xff/xff", China_data.confirmedIncr);      sprintf(str3, "n2.val=%d/xff/xff/xff", China_data.curedCount);      sprintf(str8, "n7.val=%d/xff/xff/xff", China_data.curedIncr);      sprintf(str4, "n3.val=%d/xff/xff/xff", China_data.deadCount);      sprintf(str9, "n8.val=%d/xff/xff/xff", China_data.deadIncr);      sprintf(str5, "n4.val=%d/xff/xff/xff", China_data.seriousCount);      sprintf(str10, "n9.val=%d/xff/xff/xff", China_data.seriousIncr);

數(shù)據(jù)發(fā)送

      TJC.print(str1);      TJC.print(str2);      TJC.print(str3);      TJC.print(str4);      TJC.print(str5);      TJC.print(str6);      TJC.print(str7);      TJC.print(str8);      TJC.print(str9);      TJC.print(str10);

3、將esp32的rx、tx引腳分別和串口屏的tx、rx引腳相連

4、參考文章 ：疫情監(jiān)控三部曲——在STM32F103 MCU上實(shí)現(xiàn)（裸機(jī)版） - 云+社區(qū) - 騰訊云 (tencent.com)

五、完整代碼

#include          //用于連接WiFi網(wǎng)絡(luò)#include    //用于向服務(wù)端請求數(shù)據(jù)信息#include   //用于解析返回的json數(shù)據(jù)#define TJC Serial2       //串口屏收發(fā)串口定義為串口2const char *dssid = "DOG";    //你的網(wǎng)絡(luò)名稱const char *password = "66666666"; //你的網(wǎng)絡(luò)密碼struct ncov_data{         //該結(jié)構(gòu)體用于保存數(shù)據(jù)    long currentConfirmedCount;//現(xiàn)存確診    long currentConfirmedIncr;//較昨日    long confirmedCount;//累計(jì)確診    long confirmedIncr;//較昨日    long curedCount;//累計(jì)治愈    long curedIncr;//較昨日    long seriousCount;//現(xiàn)存無癥狀    long seriousIncr;//較昨日    long deadCount;//累計(jì)死亡    long deadIncr;//較昨日    String updateTime;//更新時間};void setup() {            //做設(shè)備初始化  Serial.begin(115200);   //初始化串口波特率為115200  TJC.begin(115200);      //初始化收發(fā)串口波特率為115200  while (TJC.read() >= 0);//等待串口屏連接成功  Serial.println("");    //打印空白行  WiFi.begin(dssid,password);//連接指定wifi  while (WiFi.status() != WL_CONNECTED)  {    delay(500);    Serial.print(".");  }                    //連接中返回.....  Serial.println("WiFi connected!");//WiFi連接成功    // put your setup code here, to run once:}void loop() {  HTTPClient http;     //建立HTTPClient對象  http.begin("https://lab.isaaclin.cn/nCoV/api/overall");//向該網(wǎng)址發(fā)送http數(shù)據(jù)請求  int httpCode = http.GET();     //保存返回的狀態(tài)碼  // put your main code here, to run repeatedly:  if (httpCode > 0) // 如果狀態(tài)碼大于0說明請求過程無異常  {    if (httpCode == HTTP_CODE_OK) // 請求被服務(wù)器正常響應(yīng)，等同于httpCode == 200    {      String payload = http.getString(); // 讀取服務(wù)器返回的響應(yīng)正文數(shù)據(jù)      Serial.println(payload);           //串口打印返回的數(shù)據(jù)            ncov_data China_data;              //國內(nèi)疫情數(shù)據(jù)      ncov_data World_data;              //國外疫情數(shù)據(jù)      DynamicJsonDocument doc(1000);     //創(chuàng)建DynamicJsonDocument對象      deserializeJson(doc, payload);     //反序列化數(shù)據(jù)      JsonObject results_0 = doc["results"][0];      //將解析出的數(shù)據(jù)賦值給結(jié)構(gòu)體      China_data.currentConfirmedCount = results_0["currentConfirmedCount"].as();      China_data.currentConfirmedIncr = results_0["currentConfirmedIncr"].as();      China_data.confirmedCount = results_0["confirmedCount"].as();      China_data.confirmedIncr = results_0["confirmedIncr"].as();      China_data.curedCount = results_0["curedCount"].as();      China_data.curedIncr = results_0["curedIncr"].as();      China_data.deadCount = results_0["deadCount"].as();      China_data.deadIncr = results_0["deadIncr"].as();      China_data.seriousCount = results_0["seriousCount"].as();      China_data.seriousIncr = results_0["seriousIncr"].as();      World_data.currentConfirmedCount = results_0["globalStatistics"]["currentConfirmedCount"].as();      World_data.currentConfirmedIncr = results_0["globalStatistics"]["currentConfirmedIncr"].as();      World_data.confirmedCount = results_0["globalStatistics"]["confirmedCount"].as();      World_data.confirmedIncr = results_0["globalStatistics"]["confirmedIncr"].as();      World_data.curedCount = results_0["globalStatistics"]["curedCount"].as();      World_data.curedIncr = results_0["globalStatistics"]["curedIncr"].as();      World_data.deadCount = results_0["globalStatistics"]["deadCount"].as();      World_data.deadIncr = results_0["globalStatistics"]["deadIncr"].as();      //字符串定義      char str1[20];      char str2[20];      char str3[20];      char str4[20];      char str5[20];      char str6[20];      char str7[20];      char str8[20];      char str9[20];      char str10[20];      char str11[20];      char str12[20];      char str13[20];      char str14[20];      char str15[20];      char str16[20];      char str17[20];      char str18[20];      //使用sprintf進(jìn)行格式拼接      sprintf(str1, "n0.val=%d/xff/xff/xff", China_data.currentConfirmedCount);      sprintf(str6, "n5.val=%d/xff/xff/xff", China_data.currentConfirmedIncr);      sprintf(str2, "n1.val=%d/xff/xff/xff", China_data.confirmedCount);      sprintf(str7, "n6.val=%d/xff/xff/xff", China_data.confirmedIncr);      sprintf(str3, "n2.val=%d/xff/xff/xff", China_data.curedCount);      sprintf(str8, "n7.val=%d/xff/xff/xff", China_data.curedIncr);      sprintf(str4, "n3.val=%d/xff/xff/xff", China_data.deadCount);      sprintf(str9, "n8.val=%d/xff/xff/xff", China_data.deadIncr);      sprintf(str5, "n4.val=%d/xff/xff/xff", China_data.seriousCount);      sprintf(str10, "n9.val=%d/xff/xff/xff", China_data.seriousIncr);      //發(fā)送數(shù)據(jù)      TJC.print(str1);      TJC.print(str2);      TJC.print(str3);      TJC.print(str4);      TJC.print(str5);      TJC.print(str6);      TJC.print(str7);      TJC.print(str8);      TJC.print(str9);      TJC.print(str10);      TJC.print("page 1/xff/xff/xff");            sprintf(str11, "n10.val=%d/xff/xff/xff", World_data.currentConfirmedCount);      sprintf(str12, "n11.val=%d/xff/xff/xff", World_data.currentConfirmedIncr);      sprintf(str13, "n12.val=%d/xff/xff/xff", World_data.confirmedCount);      sprintf(str14, "n13.val=%d/xff/xff/xff", World_data.confirmedIncr);      sprintf(str15, "n14.val=%d/xff/xff/xff", World_data.curedCount);      sprintf(str16, "n15.val=%d/xff/xff/xff", World_data.curedIncr);      sprintf(str17, "n16.val=%d/xff/xff/xff", World_data.deadCount);      sprintf(str18, "n17.val=%d/xff/xff/xff", World_data.deadIncr);            TJC.print(str11);      TJC.print(str12);      TJC.print(str13);      TJC.print(str14);      TJC.print(str15);      TJC.print(str16);      TJC.print(str17);      TJC.print(str18);      TJC.print("page 0/xff/xff/xff");            //串口打印//      Serial.println("");//      Serial.println("----------------國內(nèi)疫情---------------");//      Serial.print("現(xiàn)存確診: ");Serial.println(China_data.currentConfirmedCount);//      Serial.print("累計(jì)確診: ");Serial.println(China_data.confirmedCount);//      Serial.print("累計(jì)治愈: ");Serial.println(China_data.curedCount);//      Serial.print("現(xiàn)存無癥: ");Serial.println(China_data.seriousCount);//      Serial.print("累計(jì)死亡: ");Serial.println(China_data.deadCount);//      Serial.println("----------------國外疫情---------------");//      Serial.print("現(xiàn)存確診: ");Serial.println(World_data.currentConfirmedCount);//      Serial.print("累計(jì)確診: ");Serial.println(World_data.confirmedCount);//      Serial.print("累計(jì)治愈: ");Serial.println(World_data.curedCount);//      Serial.print("累計(jì)死亡: ");Serial.println(World_data.deadCount);    }  }  else  { //未被響應(yīng)返回錯誤碼    Serial.printf("[HTTP] GET... failed, error: %s/n", http.errorToString(httpCode).c_str());  }  http.end(); // 結(jié)束當(dāng)前連接  delay(1200000);//兩分鐘發(fā)送一次請求，過于頻繁可能導(dǎo)致ip被接口封掉}

六、效果展示