#include "ESP8266WiFi.h"
    
    // Declare Variable ///////////////////////////////////////////////////////
    char GPIO0;                         // GPIO0  -> Sonoff Basic - Button
    char GPIO12;                        // GPIO12 -> Sonoff Basic - Relais
    char GPIO13;                        // GPIO13 -> Sonoff Basic - green LED
    char TRIGG1;                        // Button Trigger
    int time1;
    int time2;
    int time3;
    
    ADC_MODE(ADC_VCC);
    
    void SCAN(){
        Serial.println(); 
        Serial.println(); 
        Serial.println("***********************************");
        Serial.println("***********************************");
        // Chip-ID
        Serial.println(); 
        Serial.print("Chip-ID     : 0x");       
        Serial.println(ESP.getChipId(), HEX); 
        
        // Check VCC and Heap Memory
        Serial.print("Voltage     : ");
        Serial.print((float)ESP.getVcc() / 1000);        
        Serial.println(" V");        
        Serial.print("Real  Memory: ");
        Serial.print(ESP.getFlashChipRealSize() / 1024);
        Serial.println(" kB");               
        Serial.print("Flash Memory: ");
        Serial.print(ESP.getFlashChipSize() / 1024);     
        Serial.println(" kB");        
        Serial.print("Free  Memory: ");
        Serial.print((float)ESP.getFreeHeap() / 1024);       
        Serial.println(" kB");   
        Serial.println(); 
      
        // WiFi.scanNetworks will return the number of networks found
        Serial.println("Start Network Scan ...");
        int n = WiFi.scanNetworks();
        if (n == 0)
          Serial.println("no Networks found");
        else
        {
          Serial.print(n);
          Serial.println(" Networks found");
          Serial.println("================");
          for (int i = 0; i < n; ++i)
          {
            // Print SSID and RSSI for each network found
            Serial.print(i + 1);
            Serial.print(": ");
            Serial.print(WiFi.SSID(i));
            Serial.print(" (");
            Serial.print(WiFi.RSSI(i));
            Serial.print(")");
            Serial.println((WiFi.encryptionType(i) == ENC_TYPE_NONE)?" ":"*");
          }
          Serial.println("Scan done");
          Serial.println(); 
        }
    }
    
    void setup() {
    
      //  Configure GPIO //////////////////////////////////////////////////////
      pinMode(0, INPUT_PULLUP);
      pinMode(13, OUTPUT);
      pinMode(12, OUTPUT);
      Serial.begin(115200);
      delay(100);  
     
      // Set WiFi to station mode and disconnect from an AP if it was previously connected
      WiFi.mode(WIFI_STA);
      WiFi.disconnect();
      delay(100);
      digitalWrite(13, HIGH);    
      Serial.println("Setup done");
      time1 = millis() - 7000;
      time3 = millis();
    }
     
    void loop() {
    
      GPIO0 = digitalRead(0);
      GPIO13 = digitalRead(13);
  
      if (GPIO0 == LOW and GPIO13 == LOW and TRIGG1 == LOW) {
        digitalWrite(13, HIGH);
        TRIGG1 = HIGH;
      }
      if (GPIO0 == LOW and GPIO13 == HIGH and TRIGG1 == LOW) {
        digitalWrite(13, LOW);
        TRIGG1 = HIGH; 
      }
      if (GPIO0 == HIGH) { TRIGG1 = LOW; }
      
      time2 = millis();
      if (time2 - time1 > 7000){          
        SCAN();
        time1 = millis();
      }

      if (time2 - time3 > 500){          
        Serial.print("."); 
        time3 = millis();
      }
    }