ESP 12 : Wifi & Reboot

Lorsque la connexion wifi est perdue (par exemple un reboot de la box), l’ESP doit se reconnecter automatiquement. Ainsi, le sketch suivant, doit assurer la connexion à une borne wifi et assurer une connexion continue en servant un site web.

#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <WiFiClient.h>

# define LRED 15
# define LGREEN 12
# define LBLUE 13

const char* ssid = « xxx »;
const char* password = « xxx »;

ESP8266WebServer server(80); // Create a webserver object that listens for HTTP request on port 80

const int led = 2;
int i = 0;

void handleRoot(); // function prototypes for HTTP handlers
void handleLED();
void handleNotFound();

void setup(void)
{
analogWrite( LRED, 1023);
Serial.begin(115200); // Start the Serial communication to send messages to the computer
delay(500);
analogWrite( LRED, 0);

pinMode(led, OUTPUT);

//////////////////////////////
// IP STATIQUE
///////////////////////////
IPAddress staticIP(192, 168, 0, 39);
IPAddress gateway(192, 168, 0, 254);
IPAddress subnet(255, 255, 255, 0);
Serial.printf(« Connecting to %s\n », ssid);
// —————This was the magic WiFi reconnect fix for me
WiFi.persistent(false);
WiFi.mode(WIFI_OFF); // this is a temporary line, to be removed after SDK update to 1.5.4
WiFi.mode(WIFI_STA);
// —————END – WiFi reconnect fix
WiFi.begin(ssid, password);
WiFi.config(staticIP, gateway, subnet);
while (WiFi.status() != WL_CONNECTED)
{ delay(500);
analogWrite( LBLUE, 1023);
Serial.print(« . »);
delay(500);
analogWrite( LBLUE, 0);
i++;
if (i > 10)
ESP.restart(); //ESP.reset();
}
WiFi.setAutoReconnect(true);
WiFi.setSleepMode(WIFI_NONE_SLEEP);
Serial.println();
Serial.printf( » connected to %s\n », WiFi.SSID().c_str());
analogWrite( LBLUE, 0);
analogWrite( LGREEN, 1023);
Serial.flush();
server.on(« / », HTTP_GET, handleRoot); // Call the ‘handleRoot’ function when a client requests URI « / »
server.on(« /LED », HTTP_POST, handleLED); // Call the ‘handleLED’ function when a POST request is made to URI « /LED »
server.onNotFound(handleNotFound); // When a client requests an unknown URI (i.e. something other than « / »), call function « handleNotFound »

server.begin(); // Actually start the server
Serial.println(« HTTP server started »);

}
//////////////////////////////////
void handleRoot() { // When URI / is requested, send a web page with a button to toggle the LED
server.send(200, « text/html », « <form action=\ »/LED\ » method=\ »POST\ »><input type=\ »submit\ » value=\ »Toggle LED\ »></form> »);
}

void handleLED() { // If a POST request is made to URI /LED
digitalWrite(led, !digitalRead(led)); // Change the state of the LED
server.sendHeader(« Location », « / »); // Add a header to respond with a new location for the browser to go to the home page again
server.send(303); // Send it back to the browser with an HTTP status 303 (See Other) to redirect
}

void handleNotFound() {
server.send(404, « text/plain », « 404: Not found »); // Send HTTP status 404 (Not Found) when there’s no handler for the URI in the request
}
////////////////////////////////
void loop(void)
{
server.handleClient(); // Listen for HTTP requests from clients
i++;
delay(50);
if (i > 40)
{ i = 0;
digitalWrite(led, !digitalRead(led)); // Change the state of the LED
}
}

Dans le cas où il y a des problèmes de reconnection, pour effectuer cette opération, il faut tester la perte de la connexion à l’aide de l’instruction if(WiFi.status() != WL_CONNECTED) et dans ce cas effectuer un reboot de l’ESP avec l’instruction ESP.reset();

Exemple de sketch

 //-- LED  
 #define RedLed  12  
 #define GreenLed 13  
 #define BlueLed 15  
 //-- ESP 12  
 #include <WiFiUdp.h>  
 #include <WiFiClient.h>  
 #include <WiFiServer.h>  
 #include <SPI.h>  
 #include <ESP8266WiFi.h>  
 #include <ESP8266mDNS.h>  
 #include <ESP8266AVRISP.h>  
 #include <PubSubClient.h>  
 const char* ssid = "xxxx";  
 const char* password = "zzzz";  
 ////////////////////////////////////////////  
 void setup() {  
  pinMode(GreenLed, OUTPUT);  
  pinMode(RedLed, OUTPUT);  
  pinMode(BlueLed, OUTPUT);  
  //-- Led Bleu = Init Ok  
  Serial.begin(115200);  
  delay(10);  
  WiFi.mode(WIFI_STA);  
  WiFi.begin(ssid, password);  
  while (WiFi.status() != WL_CONNECTED) {  
   delay(500);  
   Serial.print(".");  
  }  
  Serial.println();  
  Serial.println("WIFIOK");  
  Serial.println(WiFi.localIP());  
  setColor(0, 255, 0); //-- Wifi Ok Led Bleu  
  delay(1000);  
 }  
 void loop() {  
  if (WiFi.status() != WL_CONNECTED) {  
   Serial.println("...WIFI LOST...");  
   setColor(0, 0, 255); //-- Led Rouge  
   delay(1000);  
   //-- On reboot  
   ESP.restart(); //ESP.reset();  
  }  
 }  
 void setColor(int red, int green, int blue)  
 {  
  analogWrite(RedLed, red);  
  analogWrite(GreenLed, green);  
  analogWrite(BlueLed, blue);  
 }

Ce qui donne :

………..WIFIOK
192.168.0.52
…WIFI LOST…
ets Jan 8 2013,rst cause:2, boot mode:(3,6)
load 0x4010f000, len 1264, room 16
tail 0
chksum 0x42
csum 0x42
~ld
…………………………………………………………………………………………………
WIFIOK
192.168.0.51

Autre possibilité, avec WifiMulti (exemple avec un ESP 12) :

# define LRED 15
# define LGREEN 12
# define LBLUE 13

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WiFiMulti.h>
#include <ESP8266mDNS.h>
#include <ESP8266WebServer.h>

boolean connectioWasAlive = true;

ESP8266WiFiMulti wifiMulti; // Create an instance of the ESP8266WiFiMulti class, called ‘wifiMulti’

ESP8266WebServer server(80); // Create a webserver object that listens for HTTP request on port 80

const int led = 2;
int i = 0;

void handleRoot(); // function prototypes for HTTP handlers
void handleLED();
void handleNotFound();

void monitorWiFi()
{
//Serial.print(‘<‘);
if (wifiMulti.run() != WL_CONNECTED)
{

if (connectioWasAlive == true)
{
analogWrite( LGREEN, 0);
analogWrite( LRED, 1023);
connectioWasAlive = false;
Serial.println(« Looking for WiFi « );

delay(500);
analogWrite( LRED, 0);
}
analogWrite( LBLUE, 1023);
Serial.print(« . »);
delay(500);
analogWrite( LBLUE, 0);
}
else if (connectioWasAlive == false)
{
connectioWasAlive = true;
Serial.printf( » connected to %s\n », WiFi.SSID().c_str());
analogWrite( LGREEN, 1023);
}
}

void setup(void) {
analogWrite( LRED, 1023);
Serial.begin(115200); // Start the Serial communication to send messages to the computer
delay(250);
analogWrite( LRED, 0);
Serial.println(‘\n’);

pinMode(led, OUTPUT);

wifiMulti.addAP(« xxx », « xxxx »);
wifiMulti.addAP(« xxx, « xxxx);

Serial.println(« Connecting … »);
int i = 0;
while (wifiMulti.run() != WL_CONNECTED) { // Wait for the Wi-Fi to connect: scan for Wi-Fi networks, and connect to the strongest of the networks above
analogWrite( LBLUE, 0);
delay(250);
analogWrite( LBLUE, 1023);
Serial.print(‘.’);
}
analogWrite( LRED, 0);
analogWrite( LBLUE, 0);
analogWrite( LGREEN, 1023);
Serial.println(‘\n’);
Serial.print(« Connected to « );
Serial.println(WiFi.SSID()); // Tell us what network we’re connected to
Serial.print(« IP address:\t »);
Serial.println(WiFi.localIP()); // Send the IP address of the ESP8266 to the computer

if (MDNS.begin(« esp8266 »)) { // Start the mDNS responder for esp8266.local
Serial.println(« mDNS responder started »);
} else {
Serial.println(« Error setting up MDNS responder! »);
}

server.on(« / », HTTP_GET, handleRoot); // Call the ‘handleRoot’ function when a client requests URI « / »
server.on(« /LED », HTTP_POST, handleLED); // Call the ‘handleLED’ function when a POST request is made to URI « /LED »
server.onNotFound(handleNotFound); // When a client requests an unknown URI (i.e. something other than « / »), call function « handleNotFound »

server.begin(); // Actually start the server
Serial.println(« HTTP server started »);
}

void loop(void) {
monitorWiFi();
server.handleClient(); // Listen for HTTP requests from clients
//Serial.print(‘>’);
i++;
delay(50);
if (i > 40)
{ i = 0;
//Serial.println();
digitalWrite(led, !digitalRead(led)); // Change the state of the LED
}
}

void handleRoot() { // When URI / is requested, send a web page with a button to toggle the LED
server.send(200, « text/html », « <form action=\ »/LED\ » method=\ »POST\ »><input type=\ »submit\ » value=\ »Toggle LED\ »></form> »);
}

void handleLED() { // If a POST request is made to URI /LED
digitalWrite(led, !digitalRead(led)); // Change the state of the LED
server.sendHeader(« Location », « / »); // Add a header to respond with a new location for the browser to go to the home page again
server.send(303); // Send it back to the browser with an HTTP status 303 (See Other) to redirect
}

void handleNotFound() {
server.send(404, « text/plain », « 404: Not found »); // Send HTTP status 404 (Not Found) when there’s no handler for the URI in the request
}