ESP小车控制 --物联网
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系统需求分析
目前很多信息技术业界大佬都把物联网视作继个人计算机、互联网之后，当今世界最具发展潜力的产业之一。物联网作为继互联网之后新一代的连接方式，正在有力带动传统产业转型升级，引领战略性新兴产业发展，推动社会生产和经济发展方式的深度变革。MQTT是教学中常见的物联网协议之一，MQTT协议是近几年才出现的吗？其实不然，MQTT诞生于1999年互联网初期。Ashton提出IoT概念也是在1999年，MQTT协议生逢其时。当时MIT Auto-ID Labs的Kevin Ashton为了把宝洁的供应链上的RFID标签和互联网连接起来，在1999年第一个提出了IoT这个概念。 MQTT（Message Queuing Telemetry Transport，消息队列遥测传输协议）是一个基于客户端-服务器的消息发布/订阅传输协议。
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系统初步设计，包括框架设计，功能设计
手机app 和 esp32 连接到同一个 物联网服务器平台 ，相互订阅和发布话题达到数据互传，来控制esp32 对小车进行驱动。来达到控制小车前进的目地。
客户端监控数据用的是开源的第三方物联网服务器平台 无法进入后台只能接入后订阅话题
- 系统详细设计：
（1）感知层：传感器，组网
（2）网络层：传输网的选择、说明
（3）应用层：数据处理，结果呈现
代码构架
// 电位器连接到GPIO 34(模拟ADC1_CH6)
const int potPin = 34;
// 用于存储电位器值的变量
int potValue = 0;
void setup() {
Serial.begin(115200);
delay(1000);
}
void loop() {
// 读取电位计值
potValue = analogRead(potPin);
Serial.println(potValue);
delay(500);
}
#include <AsyncTimer.h>
int pmPin = 34;
int ledPin = 2;
int ch0 = 0;
AsyncTimer timer;
int taskId = 0;
void ChangeLedLightness()
{
int val = analogRead(pmPin);
//Serial.println(val);
auto vol = analogReadMilliVolts(pmPin);
//Serial.println(vol-142);
//读取换算毫伏
int duty = val/4095.0*1024;
ledcWrite(ch0,duty);
}
void setup()
{
Serial.begin(115200) ;
analogReadResolution(12);
analogSetAttenuation(ADC_11db);
ledcSetup(ch0,1000,10);
ledcAttachPin(ledPin,ch0);
taskId = timer.setInterval(ChangeLedLightness,20);//20 ms 一次
}
void loop() {
timer.handle();
}
wifi 接入物联网控制系统
//WIFI 连接库和MQTT客户端
#include <WiFi.h>
#include <PubSubClient.h>
//***************** WiFi 账号密码************************
const char *ssid = "2580"; // Wifi 账号
const char *password = "1234567890"; // wifi 密码
// const char *ssid = "HUAWEI-5VBLX2"; // Wifi 账号
// const char *password = "d13545386916"; // wifi 密码
//**************** MQTT Broker 服务端连接****************
const char *mqtt_broker = "broker-cn.emqx.io";
const char *OutTopic = "ESP_Car/SELF";
const char *InTopic = "ESP_Car/control";
const char *mqtt_username = "ESP32_car";
const char *mqtt_password = "14789632";
const int mqtt_port = 1883;
//车灯
const int LED = 2;//到时候改到别的引脚
long lastReconnectAttempt = 0;
// ***********************车驱动*************************
const int pin26=26; //设置驱动脚
const int pin25=25;
const int pin33=33;
const int pin32=32;
int speed=255;//车速度
String state="s";//车的状态
//控制单元
void Go(){
state="t";
ledcWrite(1,0);
ledcWrite(2,speed);
ledcWrite(3,0);
ledcWrite(4,speed);
}//前进
void back(){
state="b";
ledcWrite(1,speed);
ledcWrite(2,0);
ledcWrite(3,speed);
ledcWrite(4,0);
}//后退
void left(){
state="l";
ledcWrite(1,0);
ledcWrite(2,speed);
ledcWrite(3,0);
ledcWrite(4,0);
}//左
void right(){
state="r";
//发布一个向右
ledcWrite(1,0);
ledcWrite(2,0);
ledcWrite(3,0);
ledcWrite(4,speed);
}//右
void stop(){
state="s";
ledcWrite(1,0);
ledcWrite(2,0);
ledcWrite(3,0);
ledcWrite(4,0);
}//停
//客户端变量
WiFiClient espClient;
PubSubClient client(espClient);
//闪灯次数
void re_signal(int fq){
int i = 0;
for(i;i<fq;i++){
digitalWrite(LED, HIGH);
delay(20);
digitalWrite(LED, LOW);
delay(20);
digitalWrite(LED, HIGH);
delay(20);
digitalWrite(LED, LOW);
delay(20);
}
}
void setup() {
//车驱动
ledcSetup(1,50,8);
ledcAttachPin(pin25,1);
ledcSetup(2,50,8);
ledcAttachPin(pin26,2);
ledcSetup(3,50,8);
ledcAttachPin(pin32,3);
ledcSetup(4,50,8);
ledcAttachPin(pin33,4);
//车灯
pinMode(LED, OUTPUT);
//软串口波特率
Serial.begin(115200);
lastReconnectAttempt = 0;
// connecting to a WiFi network
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.println("Connecting to WiFi..");
}
re_signal(1);
Serial.println("Connected to the WiFi network");
//connecting to a mqtt broker 连接服务端
client.setServer(mqtt_broker, mqtt_port);
client.setCallback(callback);//回调
while (!client.connected()) {
String client_id = "esp32-client-";
client_id += String(WiFi.macAddress());
Serial.printf("The client %s connects to the public mqtt broker\n", client_id.c_str());
if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {
Serial.println("Public emqx mqtt broker connected");
} else {
Serial.println("failed with state ");
Serial.println(client.state());//返回连接状态
delay(2000);
}
}
re_signal(3);
// publish and subscribe
client.publish(OutTopic, "小车车来喽！");
re_signal(3);
client.subscribe(InTopic);
}
boolean reconnect() {
if (client.connect("YSL", mqtt_username, mqtt_password)) {
// Once connected, publish an announcement...
client.publish("outTopic","小车车来喽！");
// ... and resubscribe
client.subscribe("inTopic");
}
return client.connected();
}
//回调函数（主题，内容，长度）
void callback(char *InTopic, byte *payload, unsigned int length) {
Serial.print("Message arrived in topic: ");
Serial.println(InTopic);
Serial.print("Message:");
for (int i = 0; i < length; i++) {
Serial.print((char) payload[i]);
}
if (payload[0] == 'C'&payload[1]=='#') {
//Serial.print(payload[2]-48);出来的都是字符流
switch (payload[2]) {
case '1':
digitalWrite(LED,1); // 则点亮LED。
client.publish(OutTopic, "亮");
break;
case '0':
digitalWrite(LED,0); // 则点亮LED。
client.publish(OutTopic, "咩");
break;
case 'L':
left();
re_signal(1);
client.publish(OutTopic, "左转");
break;
case 'R':
right();
re_signal(1);
client.publish(OutTopic, "右转");
break;
case 'S':
stop();
re_signal(1);
client.publish(OutTopic, "停车");
break;
case 'B':
back();
re_signal(1);
client.publish(OutTopic, "倒车");
break;
case 'G':
Go();
re_signal(1);
client.publish(OutTopic, "前进");
break;
case 'V':
client.publish(OutTopic, "速度这块容我开发！！！！");
break;
default:
client.publish(OutTopic, "好家伙，新东西？");
break;
}
}
Serial.println();
Serial.println("-----------------------");
}
void loop()
{
if (!client.connected()) {
long now = millis();
if (now - lastReconnectAttempt > 5000) {
lastReconnectAttempt = now;
// Attempt to reconnect
if (reconnect()) {
lastReconnectAttempt = 0;
}
}
} else {
// Client connected
client.loop();
}
}
esp32 wifi 只是 其中一个部分
air780e 插入手机卡 做第二阶段控制
