Can't connect to WIFI using ESP2866 and using c_str as argument for WiFi.begin()

Projects Networking, Protocols, and Devices
1

Good Day Everyone

I am having difficulty connecting to WIFI

I am using an esp2866 with USB adapter

I am using the code to light an LED
I can connect to WIFI when i use WiFi.begin("UserName", "XXXXXX")
this shows the name and pass directly to the IDE
This is not secure

my expectation:
I want to use the serial monitor to type the ssid and password

my problem:
when i change WiFi.begin("UserName", "XXXXXX")
to WiFi.begin(ssid.c_str(), pass.c_str()), it just run the do while function endlessly indicating that it is not connected
I use c_str because WiFi begin cannot recognize string

I also tried casting the the ssid and pass to const char. It did not work also

Can you help me to make this work. Thank you

Here is the code:

#include<ESP8266WiFi.h>
#include<ESP8266WebServer.h>
//#include<Wifi.h>

#define LED 2

String ssid = "";
String pass = "";

ESP8266WebServer server(80);

void setup() {
 pinMode(LED, OUTPUT);
 digitalWrite(LED, LOW);
 Serial.begin(115200);
 Serial.println("Begin");
}

void SetServerHandler() {
 if (WiFi.status() == WL_CONNECTED) {
   server.on("/LED=ON", []() {
     digitalWrite(LED, HIGH);
     String res = digitalRead(LED) == HIGH ? "ON" : "OFF";
     server.send(200, "text/html", "LED is " + res);
   });

   server.on("/LED=OFF", []() {
     digitalWrite(LED, LOW);
     String res = digitalRead(LED) == HIGH ? "ON" : "OFF";
     server.send(200, "text/html", "LED is " + res);
   });
   server.begin();
 }
}
void loop() {
 if (Serial.available()) {

   String params = Serial.readStringUntil('\n');

   if (params.startsWith("ssid")) {
     ssid = params.substring(5);
     Serial.println("ssid = [" + ssid + "]");
   } else if (params.startsWith("pass")) {
     pass = params.substring(5);
     Serial.println("pass = [" + pass + "]");
   } else if (params.startsWith("connect")) {
     //WiFi.begin("UserName", "XXXXXX"); //this is not secure but works
     //WiFi.begin(ssid, pass);
     //WiFi.begin((const char*)ssid.c_str(), (const char*)pass.c_str());//casting to const char
     WiFi.begin(ssid.c_str(), pass.c_str());
     Serial.println("Connect to " + ssid);
     int retry = 0;
     while (WiFi.status() != WL_CONNECTED) {
       retry++;
       if ((retry % 20) == 0)
         Serial.println(".");
       else
         Serial.print(".");
       delay(500);
     }
     Serial.println();
     Serial.println("Wifi connected");
     Serial.println("IP address: ");
     Serial.println(WiFi.localIP());

     SetServerHandler();
   }
 }
 server.handleClient();
}
2

my problem:
when i change WiFi.begin("UserName", "XXXXXX")
to WiFi.begin(ssid.c_str(), pass.c_str()), it just run the do while function endlessly indicating that it is not connected
I use c_str because WiFi begin cannot recognize string

I have run into a similar problem in the past.

Once you have connected to (or even just tried to connect to) an access point the ESP records the SSID and password for that access point in it's non-volatile memory.

The next time you apply power to the device it will attempt to connect to that access point again. (This will occur even if you have reprogrammed the ESP.)

If the ESP makes a successful automatic connection to that access point, probably while your software is configuring the serial port and doing other preliminary steps, your subsequent WiFi.begin statement, even with the same parameters, could cause the symptoms you mention.

DISCLAIMER: My information may be out of date as work on this situation continues. Different iterations of the ESP8266 software seem to have different idiosyncrasies.

Don

3

Your serial terminal probably sends a CR/LF at the end of a line (when you hit the return key). As you read the string until the newline character the username and password strings include the carriage return, so it won't work.

It might already work if you change your sketch to read until you get '\r' instead of '\n'.

4

Try tried to connect to different Wifi's and it does not connect when i use the Wifi begin with the c_str. I am not really sure if the code automatically connects to a Wifi in its volatile memory. I tried to turn off every wifi except one but still it does not connect. the volatile mem might not be the problem.