ConfigOnSwitch.ino

/*
This example will open a configuration portal when no WiFi configuration has been previously
entered or when a button is pushed. It is the easiest scenario for configuration but 
requires a pin and a button on the ESP8266 device. The Flash button is convenient 
for this on NodeMCU devices.
*/

#include <ESP8266WiFi.h>          //https://github.com/esp8266/Arduino

//needed for library
#include <ESP8266WebServer.h>
#include <DNSServer.h>
#include <WiFiManager.h>          //https://github.com/kentaylor/WiFiManager
// select wich pin will trigger the configuraton portal when set to LOW
// ESP-01 users please note: the only pins available (0 and 2), are shared 
// with the bootloader, so always set them HIGH at power-up
// Onboard LED I/O pin on NodeMCU board
const int PIN_LED = 2; // D4 on NodeMCU and WeMos. Controls the onboard LED.
/*Trigger for inititating config mode is Pin D3 and also flash button on NodeMCU
 * Flash button is convenient to use but if it is pressed it will stuff up the serial port device driver 
 * until the computer is rebooted on windows machines.
 */
const int TRIGGER_PIN = 0; // D3 on NodeMCU and WeMos.
/*
 * Alternative trigger pin. Needs to be connected to a button to use this pin. It must be a momentary connection
 * not connected permanently to ground. Either trigger pin will work.
 */
const int TRIGGER_PIN2 = 13; // D7 on NodeMCU and WeMos.

// Indicates whether ESP has WiFi credentials saved from previous session
bool initialConfig = false;

void setup() {
  // put your setup code here, to run once:
  // initialize the LED digital pin as an output.
  pinMode(PIN_LED, OUTPUT);
  Serial.begin(115200);
  Serial.println("\n Starting");
  WiFi.printDiag(Serial); //Remove this line if you do not want to see WiFi password printed
  if (WiFi.SSID()==""){
    Serial.println("We haven't got any access point credentials, so get them now");   
    initialConfig = true;
  }
  else{
    digitalWrite(PIN_LED, HIGH); // Turn led off as we are not in configuration mode.
    WiFi.mode(WIFI_STA); // Force to station mode because if device was switched off while in access point mode it will start up next time in access point mode.
    unsigned long startedAt = millis();
    Serial.print("After waiting ");
    int connRes = WiFi.waitForConnectResult();
    float waited = (millis()- startedAt);
    Serial.print(waited/1000);
    Serial.print(" secs in setup() connection result is ");
    Serial.println(connRes);
  }
  pinMode(TRIGGER_PIN, INPUT_PULLUP);
  pinMode(TRIGGER_PIN2, INPUT_PULLUP);
  if (WiFi.status()!=WL_CONNECTED){
    Serial.println("failed to connect, finishing setup anyway");
  } else{
    Serial.print("local ip: ");
    Serial.println(WiFi.localIP());
  }
}


void loop() {
  // is configuration portal requested?
  if ((digitalRead(TRIGGER_PIN) == LOW) || (digitalRead(TRIGGER_PIN2) == LOW) || (initialConfig)) {
     Serial.println("Configuration portal requested.");
     digitalWrite(PIN_LED, LOW); // turn the LED on by making the voltage LOW to tell us we are in configuration mode.
    //Local intialization. Once its business is done, there is no need to keep it around
    WiFiManager wifiManager;

    //sets timeout in seconds until configuration portal gets turned off.
    //If not specified device will remain in configuration mode until
    //switched off via webserver or device is restarted.
    //wifiManager.setConfigPortalTimeout(600);

    //it starts an access point 
    //and goes into a blocking loop awaiting configuration
    if (!wifiManager.startConfigPortal()) {
      Serial.println("Not connected to WiFi but continuing anyway.");
    } else {
      //if you get here you have connected to the WiFi
      Serial.println("connected...yeey :)");
    }
    digitalWrite(PIN_LED, HIGH); // Turn led off as we are not in configuration mode.
    ESP.reset(); // This is a bit crude. For some unknown reason webserver can only be started once per boot up 
    // so resetting the device allows to go back into config mode again when it reboots.
    delay(5000);
  }


  // put your main code here, to run repeatedly:

}