开关
先看看最终效果，局域网内查询并控制ESP8266端口状态（以板载LED为例），无需远程服务器，路由器掉线，或外部网络垮掉都可以用，是不是很爽？
1. 原理：
在ESP8266上建立网页服务可以以两种方式实现，作为STA或者AP。
其中STA和AP的区别在于：STA是自己接入别人的网络，AP是自己建立网络让别人接入，所以在ESP8266上建立本地网页，不论是STA还是AP模式，除了开始接入方式不同，后面的建立server及对client应答的方式都是一样的。刚好ESP8266支持STA+AP，使用WiFi.mode(WIFI_AP_STA)调用就可以了。
2. 背景
为什么需要STA+AP+OTA？
首先STA+OTA是固定搭配，ESP8266作为客户端与刷写固件的电脑连入同一个路由器，通过mDNS被发现，是无线刷固件必须的组合。而AP模式的加入可以使网页不依赖路由器通道，即使外部网络出问题的时候，手机等设备仍然能够通过连接ESP8266自己发出的接入点打开网页,与GPIO口进行交互，当然，在路由器可以接上的情况下，直接IP访问还是很方便的。
一般来说是这样的，路由器DHCP会记忆这个IP第一次分配的对应设备，除非因为IP池不够用而进行了二次分配导致该IP被占用，否则会一直分配同一个IP给同一个设备,也就是说，不用特地设置固定ip也不麻烦的。
3. 功能A（查询演示）
采用OTA方式无线更新，间隔一秒翻转点亮一次wemos板载LED，通过
1.在板子由wifi自动接入路由器时，同路由器下的设备直接访问OTA端口所在的ip地址，
2.现有wifi连接失败时，或者就是喜欢通过热点直连时，连接esp8266创建的热点"espAccessPoint"并访问192.168.4.1(默认热点IP)，
从网页读取LED的亮灭状态，其中网页每5秒自动刷新一次，可以看到“status：”后的数字0，1随时间变化。
ip访问
4.代码A
/*********
by Ningh
adapted from Arduino IDE example: Examples > Arduino OTA > BasicOTA.ino
https://arduino-esp8266.readthedocs.io/en/latest/esp8266wifi/server-examples.html
*********/
#include
#include
#include
#include
// Replace with your network credentials
const char* ssid = "your-ssid";//wifi接入
const char* password = "your-password";
const char* assid = "espAccessPoint";//创建AP热点
const char* asecret = "12345678";
WiFiServer server(80);//创建tcp server
const int ESP_BUILTIN_LED = 2;
int ledState = LOW;
unsigned long previousMillis = 0;
const long interval = 1000;
int connCount = 0;//连接失败计数
void setup() {
WiFi.mode(WIFI_AP_STA);
WiFi.softAP(assid, asecret);
WiFi.begin(ssid, password);
while (WiFi.waitForConnectResult() != WL_CONNECTED) {
delay(500);
if(connCount > 30) {//如果连续30次连不上，则跳出循环，执行后面的程序
break;
}
connCount += 1;
// ESP.restart();
}
// Hostname defaults to esp8266-[ChipID]
//ArduinoOTA.setHostname("WemosEXP");
ArduinoOTA.begin();
server.begin();//启动tcp连接
pinMode(ESP_BUILTIN_LED, OUTPUT);
}
String prepareHtmlPage(){
String htmlPage =
String("HTTP/1.1 200 OK\r\n") +
"Content-Type: text/html\r\n" +
"Connection: close\r\n" + // the connection will be closed after completion of the response
"Refresh: 5\r\n" + // refresh the page automatically every 5 sec
"\r\n" +
"" +
"" +
"Digital PIN2 status: " + String(digitalRead(ESP_BUILTIN_LED)) +
"" +
"\r\n";
return htmlPage;
}
void loop() {
ArduinoOTA.handle();
WiFiClient client = server.available();
// wait for a client (web browser) to connect
if (client){
while (client.connected()){
// 不断读取请求内容
if (client.available()){
String line = client.readStringUntil('\r');
Serial.print(line);
// wait for end of client's request, that is marked with an empty line
if (line.length() == 1 && line[0] == '\n'){
//返回响应内容
client.println(prepareHtmlPage());
break;
}
}
}
delay(1); // give the web browser time to receive the data
// close the connection:
client.flush();//注意这里必须用client.flush(),如果是client.close就会报错的
}
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= interval) {
previousMillis = currentMillis;
if (ledState == LOW) {
ledState = HIGH; // Note that this switches the LED *off*
} else {
ledState = LOW; // Note that this switches the LED *on*
}
digitalWrite(ESP_BUILTIN_LED, ledState);
}
}
5. 功能B（状态查询+控制演示）
开关
代码B
/*********
Rui Santos
Complete project details at http://randomnerdtutorials.com
Arduino IDE example: Examples > Arduino OTA > BasicOTA.ino
*********/
#include
#include
#include
#include
// Replace with your network credentials
const char* ssid = "your-ssid";
const char* password = "your-password";
const char* assid = "espAccessPoint";
const char* asecret = "12345678";
WiFiServer server(80);//创建tcp server
const int ESP_BUILTIN_LED = 2;
int connCount = 0;//连接失败计数
void setup() {
WiFi.mode(WIFI_AP_STA);
WiFi.softAP(assid, asecret);
WiFi.begin(ssid, password);
while (WiFi.waitForConnectResult() != WL_CONNECTED) {
delay(500);
if(connCount > 30) {//如果连续30次连不上，则跳出循环，执行后面的程序
break;
}
connCount += 1;
//ESP.restart();
}
// Hostname defaults to esp8266-[ChipID]
//ArduinoOTA.setHostname("WemosEXP");
ArduinoOTA.begin();
server.begin();//启动tcp连接
pinMode(ESP_BUILTIN_LED, OUTPUT);
}
String prepareHtmlPage(){
String htmlPage =
String("HTTP/1.1 200 OK\r\n") +
"Content-Type: text/html\r\n" +
"Connection: close\r\n" + // the connection will be closed after completion of the response
// "Refresh: 5\r\n" + // refresh the page automatically every 5 sec
"\r\n" +
" \n"+
"Digital PIN2 status: "+String(digitalRead(ESP_BUILTIN_LED))+"
\n"+
"
"+
"
"+
"" +
"\r\n";
return htmlPage;
}
void loop() {
ArduinoOTA.handle();
WiFiClient client = server.available();
// wait for a client (web browser) to connect
if (client){
while (client.connected()){
// 不断读取请求内容
if (client.available()){
String line = client.readStringUntil('\r');
if ( line.indexOf("LEDON") > 0 ) { digitalWrite(ESP_BUILTIN_LED, LOW); }
else if ( line.indexOf("LEDOFF") > 0 ) { digitalWrite(ESP_BUILTIN_LED, HIGH); }
// wait for end of client's request, that is marked with an empty line
if (line.length() == 1 && line[0] == '\n'){
//返回响应内容
client.println(prepareHtmlPage());
break;
}
}
}
delay(1); // give the web browser time to receive the data
// close the connection:
client.flush();//注意这里必须用client.flush(),如果是client.close就会报错的
}
}
OK,功能搞定！但是这个好像有那里不对～～虽然为了可复用性，我一向推崇bare minimum，但是什么都不加，这页面实在是外表有些low啊，根本没法混。算了，必须承认极简不是简陋，拿不出手咋办呢？好办！只要在页面加入一些css样式表就可以了，这样即不影响代码结构，又不需要加载js等其它控件，很节约资源了。（js等如果需要断网使用则要放在本地，涉及到spiffs存储，it's another story，and getting more and more complicated，先打住，如果以后实在要用到ajax再说吧）
" \n"+后面加上
"\n"+
"LED Control \n"+
"\n"+
"\n"+
"\n"+
开关
6.代码C
/*********
By Ningh
adapted from Arduino IDE example: Examples > Arduino OTA > BasicOTA.ino
with reference to https://lastminuteengineers.com/creating-esp8266-web-server-arduino-ide/
*********/
#include
#include
#include
#include
// Replace with your network credentials
const char* ssid = "your-ssid";
const char* password = "your-password";
const char* assid = "espAccessPoint";
const char* asecret = "12345678";
WiFiServer server(80);//创建tcp server
const int ESP_BUILTIN_LED = 2;
int connCount = 0;//连接失败计数
void setup() {
WiFi.mode(WIFI_AP_STA);
WiFi.softAP(assid, asecret);
WiFi.begin(ssid, password);
while (WiFi.waitForConnectResult() != WL_CONNECTED) {
delay(500);
if(connCount > 30) {//如果连续30次连不上，则跳出循环，执行后面的程序
break;
}
connCount += 1;
//ESP.restart();
}
// Hostname defaults to esp8266-[ChipID]
//ArduinoOTA.setHostname("WemosEXP");
ArduinoOTA.begin();
server.begin();//启动tcp连接
pinMode(ESP_BUILTIN_LED, OUTPUT);
}
String prepareHtmlPage(){
String htmlPage =
String("HTTP/1.1 200 OK\r\n") +
"Content-Type: text/html\r\n" +
"Connection: close\r\n" + // the connection will be closed after completion of the response
"\r\n" +
" \n"+
"\n"+
"LED Control \n"+
"\n"+
"\n"+
"\n"+
"Digital PIN2 status: "+String(digitalRead(ESP_BUILTIN_LED))+"
\n"+
"
"+
"
"+
"" +
"\r\n";
return htmlPage;
}
void loop() {
ArduinoOTA.handle();
WiFiClient client = server.available();
// wait for a client (web browser) to connect
if (client){
while (client.connected()){
// 不断读取请求内容
if (client.available()){
String line = client.readStringUntil('\r');
if ( line.indexOf("LEDON") > 0 ) { digitalWrite(ESP_BUILTIN_LED, LOW); }
else if ( line.indexOf("LEDOFF") > 0 ) { digitalWrite(ESP_BUILTIN_LED, HIGH); }
// Serial.print(line);
// wait for end of client's request, that is marked with an empty line
if (line.length() == 1 && line[0] == '\n'){
//返回响应内容
client.println(prepareHtmlPage());
break;
}
}
}
delay(1); // give the web browser time to receive the data
// close the connection:
client.flush();//注意这里必须用client.flush(),如果是client.close会报错的
}
}
补充要点：esp8266建立AP密码至少要8位，不然虽然不会报错（对，小坑），实际上是不会成功建立热点的，注意！