Wiring & Programming ESP8266 12/12E / NodeMCU as WiFi Remote Client/Server Mode

Another illustration how to wire the ESP8266 as server and client mode, therefore there is no need to use a router or smart phones to interact/communicate to the ESP8266, this is direct communication between 2 ESP module as server and client mode, ones the code is loaded the ESP8266 coded as server the client ESP8266 will automatically connect to the ESP8266 Server Access Point. As you can see the diagram on the ESP8266 client the push button is attach to pin D2 map on Arduino as GPIO pin 4 when button is pressed it will send a command to the server as value of 1 then the server will turn the D2/GPIO 4 to HIGH then LED light will turn on.

Required Components

ESP8266 12/12E, ESP8266 7, ESP8266 NodeMCU, ESPDuino, WeMos.
USB TTL UART / (Flashing/Programming the ESP8266 Module)
Push Button
Resistors
LED
Jumper Wire / DuPont Wire
Solder Less Bread Board
AA Battery

Wiring Guide

Programming / Flashing the ESP8266 12/12E
You need to install Arduino 1.6.8 from the Arduino website. available for Windows, Mac OS, and Linux (32 and 64 bit).
Open Arduino IDE and open the Preferences window then add {http://arduino.esp8266.com/stable/package_esp8266com_index.json} without bracket into Additional Board Manager URLs field. Note you can add multiple url separating them with commas. > http://arduino.esp8266.com/stable/package_esp8266com_index.json

Or you can follow this steps. http://www.14core.com/arduino-ide-with-esp8266-integration-for-ease-programming/

Source Code for Server

/* 
14CORE | ESP8266 to ESP8266 Remote Client & Server Test
/------------------------ SERVER ---------------------/
*/

#include <ESP8266WiFi.h>
const char APName[] = "SERVER";
const char WiFiSec[] = "1234567890";  //Set wifi password
//const char WiFiSec[] = "" //Set AP np password

const int R0 = 15;
WiFiServer server(80);

void setup() {
  Serial.begin(115200);
  pinMode(R0, OUTPUT);
  digitalWrite(R0, LOW);
  WiFi.mode(WIFI_AP);
  WiFi.softAP(WifiSec, APName);   
  server.begin();
}

void loop() {
  WiFiClient client = server.available();   // If client is connected
  if (!client) { return;}
  //Read client request
  String req = client.readStringUntil('\r');    
  if (req.indexOf("/R0/0") != -1) val=0;
  if (req.indexOf("/R0/1") != -1) val=1;
  digitalWrite(LED_PIN, val);  
  client.flush();
 
}

14CORE | ESP8266 to ESP8266 Remote Client & Server Test

/------------------------ SERVER ---------------------/

#include <ESP8266WiFi.h>

const char APName[] = "SERVER";

const char WiFiSec[] = "1234567890"; //Set wifi password

//const char WiFiSec[] = "" //Set AP np password

const int R0 = 15;

WiFiServer server(80);

void setup() {

Serial.begin(115200);

pinMode(R0, OUTPUT);

digitalWrite(R0, LOW);

WiFi.mode(WIFI_AP);

WiFi.softAP(WifiSec, APName);

server.begin();

}

void loop() {

WiFiClient client = server.available(); // If client is connected

if (!client) { return;}

//Read client request

String req = client.readStringUntil('\r');

if (req.indexOf("/R0/0") != -1) val=0;

if (req.indexOf("/R0/1") != -1) val=1;

digitalWrite(LED_PIN, val);

client.flush();

}

Source Code for Client

/* 
14CORE | ESP8266 to ESP8266 Remote Client & Server Test
/------------------------ CLIENT ---------------------/
*/

#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>

const char* ssid     = "SERVER"; //AP Name (Server Name)
const char* password = "1234567890";  //Set wifi password
//const char* password = "" //Open no password
const char* host = "http://192.168.4.1";  //Default IP of ESP8266
String stateVal="0";

int val1;
const int inVal1 = 5; // Pin Push Button

HTTPClient http;
void setup() {
  Serial.begin(115200);
  delay(10);
  Serial.print("CONNECTED TO AP: ");
  Serial.println(ssid);
  WiFi.mode(WIFI_STA); 
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
  delay(500);
  Serial.print(".......");
  delay(500);
  }
  Serial.println("CONNECTED...");  
}
void loop(){
 val1=digitalRead(inVal1); 
  if (val1 == 1){  //Turn val1 to HIGH state
    stateVal="1";}
   else{
    stateVal="0"; 
  }

if(WiFi.status() != WL_CONNECTED){
  WiFi.begin(ssid, password);
  delay(500);
}else{
  http.begin("192.168.4.1", 80, "/led/"+stateVal);
  int httpCode1 = http.GET(); //get value 
  delay(100);   
	}
}

14CORE | ESP8266 to ESP8266 Remote Client & Server Test

/------------------------ CLIENT ---------------------/

#include <ESP8266WiFi.h>

#include <ESP8266HTTPClient.h>

const char* ssid = "SERVER"; //AP Name (Server Name)

const char* password = "1234567890"; //Set wifi password

//const char* password = "" //Open no password

const char* host = "http://192.168.4.1"; //Default IP of ESP8266

String stateVal="0";

int val1;

const int inVal1 = 5; // Pin Push Button

HTTPClient http;

void setup() {

Serial.begin(115200);

delay(10);

Serial.print("CONNECTED TO AP: ");

Serial.println(ssid);

WiFi.mode(WIFI_STA);

WiFi.begin(ssid, password);

while (WiFi.status() != WL_CONNECTED) {

delay(500);

Serial.print(".......");

delay(500);

}

Serial.println("CONNECTED...");

}

void loop(){

val1=digitalRead(inVal1);

if (val1 == 1){ //Turn val1 to HIGH state

stateVal="1";}

else{

stateVal="0";

}

if(WiFi.status() != WL_CONNECTED){

WiFi.begin(ssid, password);

delay(500);

}else{

http.begin("192.168.4.1", 80, "/led/"+stateVal);

int httpCode1 = http.GET(); //get value

delay(100);

}

Downloads

Download ESP8266 HTTP Client Library | Zip
Download ESP8266 WiFi Code Library | Zip

Wiring & Programming ESP8266 12/12E / NodeMCU as WiFi Remote Client/Server Mode

10 thoughts on “Wiring & Programming ESP8266 12/12E / NodeMCU as WiFi Remote Client/Server Mode”

Prince
at
Permalink

Hi sir,

I am tring to use your code but its seems at the server side it say’s

‘val’ was not decleared in this scope.

How to fix this. Thank you.
Reply
- 14core EditorPost author
  at
  Permalink
  
  Hi! Please check your code there is no variable ‘val’ declared in server code.
  Reply
kolio
at
Permalink

‘digtalRead’ was not declared in this scope
Reply
- 14core EditorPost author
  at
  Permalink
  
  Hi! Kelio.. the code above has been fix. actually it suppose to be digitalRead not digtalRead. :)
  Reply
  - 14core EditorPost author
    at
    Permalink
    
    The schematic diagram has been updated. Thank you very much for your concern.. :)
    Reply
kolio
at
Permalink

need to be:
if (req.indexOf(“/led/0”) != -1) val=0;
if (req.indexOf(“/led/1”) != -1) val=1;
Reply
Daniel
at
Permalink

Soy Daniel de Valencia (España) . Me gustaría hablarte de un pequeño proyecto que tengo en mente. Como conectar entre si dos esp8266-01
Uno como cliente con entrada gpio2 de un sensor de lluvia, que manda orden ( cuando llueve) durante 20 segundos al otro esp8266-01 como servidor,
con salida por gpio2 a un relé, que hace que baje la persiana de una ventana.
La idea es meter el esp8266-01 (servidor) dentro de la caja empotrada de los pulsadores de subir/bajar la persiana.
La cuestión es que lo quiero hacer inalámbricamente.
Es posible hacer el proyecto?
He mirado mucho por internet y no he visto nada, podríais echarme una mano
Mi problema es, que de programación, NO tengo nada de idea. ¿Tu podrías desarrollar el código (sketch)que hiciera funcionar mi proyecto?

Muchas Gracias por la atención, espero tu ayuda. Un abrazo.

dazallu@hotmail.com
Reply
Umer
at
Permalink

i have the val not declared in scope problem please help
Reply
- 14core EditorPost author
  at
  Permalink
  
  which value is not declared? most provably that issue is come from the declared variables, see true it that all variables are properly utilize/ :D
  Reply
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