Control Devices Over WiFi Using Phone without Router (Tutorial-4)

Nodemcu is a great WiFi chip, that can be used in several wireless applications. In my previous post, i showed you guys how to control devices using Nodemcu and Android Phone, and i received overwhelming response from you guys, and all due to this, my last post "Controlling Devices Using Nodemcu", is now one of the popular posts of my blog.
But there was one dependency in that project, the involvement of WiFi router. In the last post, first you have to connect Nodemcu with the Router and then you have to connect the Android Phone with the same router, but as Nodemcu can behave as Access Point, so we can bypass the router and directly connect our Android Phone with Nodemcu, by doing some minor changes in the Nodemcu Code.
The Block Diagram is as follow:

Block Diagram

The Updated Arduino IDE Code is as follow:

#include <DHT.h>  
#include <ESP8266WiFi.h>  
#include <WiFiClient.h>  
#define DHTPIN D5  
#define DHTTYPE DHT11  
DHT dht(DHTPIN, DHTTYPE);  
#define RELAY1 D1  
#define RELAY2 D2  
#define RELAY3 D6  
#define RELAY4 D7  
const char* ssid = "Nodemcu";  
const char* password = "12345678";  
WiFiServer server(5000);  
#define OUT_BUFFER_SIZE  6u  
char Out_Buffer[OUT_BUFFER_SIZE] = { 0 };  
char In_Buffer;  
void setup()  
{  
  delay(100);  
  Serial.begin(115200);  
  pinMode(RELAY1, OUTPUT);  
  pinMode(RELAY2, OUTPUT);  
  pinMode(RELAY3, OUTPUT);  
  pinMode(RELAY4, OUTPUT);  
  digitalWrite(RELAY1, LOW);  
  digitalWrite(RELAY2, LOW);  
  digitalWrite(RELAY3, LOW);  
  digitalWrite(RELAY4, LOW);  
  dht.begin();  
  delay(10);  
  // Create Access Point  
  WiFi.softAP("Configuting Access Point..");  
  WiFi.softAP(ssid, password);  
  IPAddress myIP = WiFi.softAPIP();  
  Serial.println("Access Point IP is: ");  
  Serial.println(myIP);  
  // Start the server  
  server.begin();  
  Serial.println("Server started");  
}  
void loop()   
{  
  static uint32_t dht_timestamp = 0;  
  // Check if a client has connected  
  WiFiClient client = server.available();  
  if (!client)   
  {  
   return;  
  }  
  // Wait until the client sends some data  
  Serial.println("new client");  
  while( client.connected() )  
  {  
   if( client.available() )  
   {  
    // Read Data  
    In_Buffer = client.read();  
    In_Buffer = 0x0F & In_Buffer;  
    // Relay 1  
    if( In_Buffer & 0x01 )  
    {  
     digitalWrite(RELAY1, HIGH);  
     Serial.println("Relay1 On");  
    }  
    else  
    {  
     digitalWrite(RELAY1, LOW);  
     Serial.println("Relay1 Off");  
    }  
    // Relay 2  
    if( In_Buffer & 0x02 )  
    {  
     digitalWrite(RELAY2, HIGH);  
     Serial.println("Relay2 On");  
    }  
    else  
    {  
     digitalWrite(RELAY2, LOW);  
     Serial.println("Relay2 Off");  
    }  
    // Relay 3  
    if( In_Buffer & 0x04 )  
    {  
     digitalWrite(RELAY3, HIGH);  
     Serial.println("Relay3 On");  
    }  
    else  
    {  
     digitalWrite(RELAY3, LOW);  
     Serial.println("Relay3 Off");  
    }  
    // Relay 4  
    if( In_Buffer & 0x08 )  
    {  
     digitalWrite(RELAY4, HIGH);  
     Serial.println("Relay4 On");  
    }  
    else  
    {  
     digitalWrite(RELAY4, LOW);  
     Serial.println("Relay4 Off");  
    }  
   }  
   if ( millis() - dht_timestamp > 2000ul )  
   {  
    uint8_t h = dht.readHumidity();  
    uint8_t t = dht.readTemperature();  
    snprintf(Out_Buffer,OUT_BUFFER_SIZE,"%d,%d",t,h);  
    // Serial.println(Out_Buffer);  
    client.print(Out_Buffer);  
    dht_timestamp = millis();  
   }  
  }  
  client.stop();  
}

You can compare this code, with the code from the last post, and you will see, the changes are very less, see the following comparison snapshot.

Changes

After flashing the above code in Nodemcu, first of all you have to connect your Android Phone with the Nodemcu.
In code the following lines are written, which is your WiFi name and Password.

 const char* ssid = "Nodemcu";  
 const char* password = "12345678";  

Just follow the procedure as given in images below.

Search For the Access Point Name "Nodemcu".

Enter the Nodemcu Password.

Enter the Server IP which in most case will be 192.168.4.1

In most of the cases, the server IP will remain 192.168.4.1, but still its better to check the IP address of Nodemcu, by sending it over the serial port. Rest all of the things are same and I don't want to post the same content again and again, you can read from that post.

Arduino code can be copied and pasted from the links given above, while Android APK can be downloaded from this link.