Wiring ESP8266 WiFi Transceiver on Arduino with Relay

In this illustration we will going to wire the ESP8266 Module on Arduino but before we can proceed we need to setup the ESP8266 module using AT-COMMAND please refer to this link. As you can see the illustration below our host control is the Arduino MCU board that controls the ESP8266 and the 4 channel relay.

ESP8266 AT COMMAND

By removing the ATMEGA328P Chip we consider that were going to use the TTL UART of the Arduino.

Sometimes the size of the message from ESP8266 is big for Arduino, you need to change the buffer which is defined in “HardwareSerial.h” it is located in directory “\arduino\hardware\avr\cores\arduino\HardwareSerial.h” and see the
“ #define SERIAL_BUFFER_SIZE 64” the default size of the buffer is 64 you need to change to bigger number, for example 256 or more.

Required Component

Arduino UNO
ESP8266 V1
4 Channel Relay Board or Shield
Jumper Wires / DuPont Wires
Solder Less Breadboard
Home Appliance for Testing
Android Phone or Tablet

Wiring Diagram Schematics

Arduino Sketch Code

/*
ESP8266 library
Connection:

UNO board Connection

ESP8266_TX->RX(Arduino Digital Pin 10)
ESP8266_RX->TX(Arduino Digital Pin 11)
ESP8266_CH_PD->3.3V
ESP8266_VCC->3.3V
ESP8266_GND->GND

When you want to output the debug information, please use DebugSerial. For example,
DebugSerial.println("hello");
*/

//#define SSID       "14CORE"
//#define PASSWORD   "14255252"

#define SSID "14COREHOME" 
#define PASSWORD "25802514"
#include "uartWIFIUNO.h" // Can be downloaded below on this page
#include <SoftwareSerial.h>

WIFIUNO wifi;

extern int chlID;

// set pin numbers:
//const int ledPin = 13; // the number of the LED pin
const int relay1 =  2; // Relay In 1 Defined at Arduino Pin 2
const int relay2 =  3; // Relay In 2 Defined at Arduino Pin 3
const int relay3 =  4; // Relay In 3 Defined at Arduino Pin 4
const int relay4 =  5; // Relay In 4 Defined at Arduino Pin 5

boolean device1 = false;
boolean device2 = false;
boolean device3 = false;
boolean device4 = false;


void setup(){
  
 // pinMode(ledPin, OUTPUT); 
 
  pinMode(relay1, OUTPUT); 
  pinMode(relay2, OUTPUT);
  pinMode(relay3, OUTPUT);
  pinMode(relay4, OUTPUT);
  
  //pinMode(ESP8266_CHPD, OUTPUT);
  //digitalWrite(ESP8266_CHPD,LOW);
  
  digitalWrite(relay1,LOW);
  digitalWrite(relay2,LOW);
  digitalWrite(relay3,LOW);
  digitalWrite(relay4,LOW);
  
   DebugSerial.println("ESP8266 Server v0.21");
  
  
  if(!wifi.begin())
  {
  	DebugSerial.println("Begin error");
  }
  bool b = wifi.Initialize(STA, SSID, PASSWORD);
  if(!b)
  {
    DebugSerial.println("Init error");
  }
  delay(8000);  //make sure the module can have enough time to get an IP address 
  String ipstring  = wifi.showIP();
  DebugSerial.println(ipstring); //show the ip address of module
  
  delay(1000);
  wifi.confMux(1);
  delay(100);
  if(wifi.confServer(1,80))
	DebugSerial.println("Server is set up");
	
}
void loop()
{
  
  char buf[500];
  int iLen = wifi.ReceiveMessage(buf);
  
  if(iLen > 0)
  {
    
      DebugSerial.print(buf);
      //delay(300);
         
       if (strncmp(buf, "GET /?status1=1", 15) == 0) {               
           //DebugSerial.print("RELAY 1 ON");
           digitalWrite(relay1, HIGH); 
           device1 = true;           
       }   
       else if (strncmp(buf, "GET /?status1=0", 15) == 0) {               
           //DebugSerial.print("RELAY 1 OFF");
           digitalWrite(relay1, LOW); 
           device1 = false;           
       } 
       
          
    
    if (strncmp(buf, "GET /?status2=1", 15) == 0) {               
           //DebugSerial.print("RELAY 2 ON");
           digitalWrite(relay2, HIGH); 
           device2 = true;           
       }   
    else if (strncmp(buf, "GET /?status2=0", 15) == 0) {               
           //DebugSerial.print("RELAY 2 OFF");
           digitalWrite(relay2, LOW); 
           device2 = false;           
       } 
       
 
      
      String cmd;
      cmd = "HTTP/1.1 200 OK\r\n";
      cmd += "Content-Type: text/html\r\n";
      cmd += "Connection: close\r\n";
      //cmd += "Refresh: 15\r\n";
      cmd += "\r\n";
      //cmd += "<!DOCTYPE HTML>\r\n";
      cmd += "<html>\r\n";
      //cmd += "<header><title>ESP8266 Webserver</title><h1>\"14CORE ESP8266 Control Center\"</h1></header>";
      
      
      if(device1){
        cmd +=("<br/>Device1  : ON");
      }
      else{
        cmd +=("<br/>Device1  : OFF");
      }
      
      if(device2){
        cmd +=("<br/>Device2  : ON");
      }
      else{
        cmd +=("<br/>Device2  : OFF");
      }
      
      
       if(device3){
        cmd +=("<br/>Device3  : ON");
      }
      else{
        cmd +=("<br/>Device3  : OFF");
      }
      
      if(device4){
        cmd +=("<br/>Device4  : ON");
      }
      else{
        cmd +=("<br/>Device4  : OFF");
      }
      
      cmd += "<html>\r\n";

        wifi.Send(chlID,cmd);
        //delay(200);
        wifi.closeMux(chlID);
	//delay(1000);
  

  }
}

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ESP8266 library

Connection:

UNO board Connection

ESP8266_TX->RX(Arduino Digital Pin 10)

ESP8266_RX->TX(Arduino Digital Pin 11)

ESP8266_CH_PD->3.3V

ESP8266_VCC->3.3V

ESP8266_GND->GND

When you want to output the debug information, please use DebugSerial. For example,

DebugSerial.println("hello");

//#define SSID "14CORE"

//#define PASSWORD "14255252"

#define SSID "14COREHOME"

#define PASSWORD "25802514"

#include "uartWIFIUNO.h" // Can be downloaded below on this page

#include <SoftwareSerial.h>

WIFIUNO wifi;

extern int chlID;

// set pin numbers:

//const int ledPin = 13; // the number of the LED pin

const int relay1 = 2; // Relay In 1 Defined at Arduino Pin 2

const int relay2 = 3; // Relay In 2 Defined at Arduino Pin 3

const int relay3 = 4; // Relay In 3 Defined at Arduino Pin 4

const int relay4 = 5; // Relay In 4 Defined at Arduino Pin 5

boolean device1 = false;

boolean device2 = false;

boolean device3 = false;

boolean device4 = false;

void setup(){

// pinMode(ledPin, OUTPUT);

pinMode(relay1, OUTPUT);

pinMode(relay2, OUTPUT);

pinMode(relay3, OUTPUT);

pinMode(relay4, OUTPUT);

//pinMode(ESP8266_CHPD, OUTPUT);

//digitalWrite(ESP8266_CHPD,LOW);

digitalWrite(relay1,LOW);

digitalWrite(relay2,LOW);

digitalWrite(relay3,LOW);

digitalWrite(relay4,LOW);

DebugSerial.println("ESP8266 Server v0.21");

if(!wifi.begin())

{

DebugSerial.println("Begin error");

}

bool b = wifi.Initialize(STA, SSID, PASSWORD);

if(!b)

{

DebugSerial.println("Init error");

}

delay(8000); //make sure the module can have enough time to get an IP address

String ipstring = wifi.showIP();

DebugSerial.println(ipstring); //show the ip address of module

delay(1000);

wifi.confMux(1);

delay(100);

if(wifi.confServer(1,80))

DebugSerial.println("Server is set up");

}

void loop()

{

char buf[500];

int iLen = wifi.ReceiveMessage(buf);

if(iLen > 0)

{

DebugSerial.print(buf);

//delay(300);

if (strncmp(buf, "GET /?status1=1", 15) == 0) {

//DebugSerial.print("RELAY 1 ON");

digitalWrite(relay1, HIGH);

device1 = true;

}

else if (strncmp(buf, "GET /?status1=0", 15) == 0) {

//DebugSerial.print("RELAY 1 OFF");

digitalWrite(relay1, LOW);

device1 = false;

}

if (strncmp(buf, "GET /?status2=1", 15) == 0) {

//DebugSerial.print("RELAY 2 ON");

digitalWrite(relay2, HIGH);

device2 = true;

}

else if (strncmp(buf, "GET /?status2=0", 15) == 0) {

//DebugSerial.print("RELAY 2 OFF");

digitalWrite(relay2, LOW);

device2 = false;

}

String cmd;

cmd = "HTTP/1.1 200 OK\r\n";

cmd += "Content-Type: text/html\r\n";

cmd += "Connection: close\r\n";

//cmd += "Refresh: 15\r\n";

cmd += "\r\n";

//cmd += "<!DOCTYPE HTML>\r\n";

cmd += "<html>\r\n";

//cmd += "<header><title>ESP8266 Webserver</title><h1>\"14CORE ESP8266 Control Center\"</h1></header>";

if(device1){

cmd +=("<br/>Device1 : ON");

}

else{

cmd +=("<br/>Device1 : OFF");

}

if(device2){

cmd +=("<br/>Device2 : ON");

}

else{

cmd +=("<br/>Device2 : OFF");

}

if(device3){

cmd +=("<br/>Device3 : ON");

}

else{

cmd +=("<br/>Device3 : OFF");

}

if(device4){

cmd +=("<br/>Device4 : ON");

}

else{

cmd +=("<br/>Device4 : OFF");

}

cmd += "<html>\r\n";

wifi.Send(chlID,cmd);

//delay(200);

wifi.closeMux(chlID);

//delay(1000);

}

Arduino Wifi with ESP8266 Code Library

Download The Arduino ESP8266 Code Library Here | Zip
Download UARTWIFIUNO Library Here | Zip

Wiring ESP8266 WiFi Transceiver on Arduino with Relay

Tagged on: Access Control AT Command Basic Internet of Thing ESP8266 How to flash the ESP8266 Internet of Things

19 thoughts on “Wiring ESP8266 WiFi Transceiver on Arduino with Relay”

yogi
at
Permalink

webserver_uno.ino:6:65: fatal error: uartWIFIUNO.h: No such file or directory
compilation terminated.
Error compiling.

hello sir i am getting this error
i am using same code as you given above
My IDE is ARDUINO 1.6.5
Reply
- 14core EditorPost author
  at
  Permalink
  
  Hi! Yogi,
  
  Download the Code Library named
  uartWIFIUNO.h <----- and placed it into your Arduino Library located at My Documents/ Arduino / Libraries just copy the whole directory and phase. Let me know if you still having an error compiling the code above.
  Reply
14core EditorPost author
at
Permalink

Hi Yogi,

I guess there some issue with the library it think it is absolute….
#include “ESP8266.h >
Use this library > https://github.com/itead/ITEADLIB_Arduino_WeeESP8266

1. Make it sure, you have complete library as required for the sketch code,
#include “ESP8266.h > Download it Here “Use this library > https://github.com/itead/ITEADLIB_Arduino_WeeESP8266”
You don’t need to download this library.
2. Make it sure you place a 200uf capacitor between GND and VCC to stabilize the logic voltage going to ESP8266.
3. Try fist using USB Serial Communication by placing the pin to ESP TX and RX to pin 0,& 1, Test the communication between the ESP8266 to Arduino by using AT Command.
———
Reply
alberes
at
Permalink

hello, my code’re error when checking
‘Exit status 1
compiling error.
how can I fix
Reply
Chinmay
at
Permalink

Error compiling.
Dear sir I am getting this error……..
………………………………………………………………………………………………………………………………………………
Arduino: 1.6.8 (Windows 7), Board: “Arduino/Genuino Uno”

C:\Users\Chinmay\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\1.6.5-947-g39819f0\libraries\ESP8266WiFi\examples\WiFiScan\WiFiScan.ino:23:65: fatal error: uartWIFIUNO.h: No such file or directory

#include “uartWIFIUNO.h” // Can be downloaded below on this page

^

compilation terminated.

exit status 1
Error compiling for board Arduino/Genuino Uno.

This report would have more information with
“Show verbose output during compilation”
option enabled in File -> Preferences.
Reply
rahmat
at
Permalink

where is uartWIFIUNO.h sir….? I cannot find it in your page and code library on your post…
please help me to solve the error
include “uartWIFIUNO.h” // Can be downloaded below on this page

^

compilation terminated.

exit status 1
Error compiling for board Arduino/Genuino Uno.

This report would have more information with
“Show verbose output during compilation”
option enabled in File -> Preferences.
Reply
- 14core EditorPost author
  at
  Permalink
  
  You can download the library here :
  http://www.14core.com/wp-content/uploads/2016/11/ESP8266UNO.rar
  Reply
  - rahmat
    at
    Permalink
    
    sir i succes to added library to Arduino IDE, and succes to compile and upload sketch to arduino UNO. But i find in serial monitor, that ”
    AT+RST
    Module have no response
    Begin error
    Init error
    please tell me about this error..
    my email : [email protected]
    Reply
    - 14core EditorPost author
      at
      Permalink
      
      There are two possible error in your case first is your serial communication is busy, second is if your using Arduino or the code below try to shift your serial communication RX = 0; & TX = 1; add 100uf capacitor to GND and VCC to your ESP8266 module, then use coolterm serial tool to verify that your ESP8266 module is connected in a proper way.
      
      Regards
      Reply
Günter
at
Permalink

Hi,
i like your instruction and got it to work…
I have some issues with the schematics. It would be great when the pinout of the esp8266-01 would be like its on the pc board.
Sorry for the bad english but i hope you know what i mean.
Reply
murrali krishna
at
Permalink

how to know the ip address of esp8266 wifi module
Reply
- 14core EditorPost author
  at
  Permalink
  
  Serial or software serial, open your serial monitor then connect to the port.
  you can used Arduino Serial Monitor, Putty, TermCool any Serial tools or Use LCD to print the IP Address of ESP82XX | lcd.println(IP Address: ); lcd.print(ipstring);
  ———————————————————
  String ipstring = wifi.showIP();
  DebugSerial.println(ipstring);
  ——————————————————–
  Reply
arunkumar
at
Permalink

sir one doubt the library pasting is in rar format or in extract file format
Reply
- 14core EditorPost author
  at
  Permalink
  
  ?????? you need to extract the file which is in the rar file then then upload the code using your IDE. don’t forget the code libraries to place in your code library directory. :)
  Reply
Parth Dangroshiya
at
Permalink

Hi sir,

“Wiring ESP8266 WiFi Transceiver on Arduino with Relay” program run but actually,

when can i firmware in esp8266-01?
when can i use “at cammad “?

i am reading but no any idea firmware and at cammand.

please explain me.
Reply
Avinash
at
Permalink

I am getting this error
In file included from C:\Users\NEXUS\OneDrive\Documents\Arduino\sketch_mar29a\sketch_mar29a.ino:22:0:

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO/uartWIFIUNO.h:67:0: warning: “OPEN” redefined

#define OPEN 1

^

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO/uartWIFIUNO.h:55:0: note: this is the location of the previous definition

#define OPEN 0

^

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO/uartWIFIUNO.h:75:0: warning: “SERIAL_TX_BUFFER_SIZE” redefined

#define SERIAL_TX_BUFFER_SIZE 128

^

In file included from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Arduino.h:232:0,

from sketch\sketch_mar29a.ino.cpp:1:

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/HardwareSerial.h:46:0: note: this is the location of the previous definition

#define SERIAL_TX_BUFFER_SIZE 64

^

In file included from C:\Users\NEXUS\OneDrive\Documents\Arduino\sketch_mar29a\sketch_mar29a.ino:22:0:

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO/uartWIFIUNO.h:76:0: warning: “SERIAL_RX_BUFFER_SIZE” redefined

#define SERIAL_RX_BUFFER_SIZE 128

^

In file included from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Arduino.h:232:0,

from sketch\sketch_mar29a.ino.cpp:1:

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/HardwareSerial.h:53:0: note: this is the location of the previous definition

#define SERIAL_RX_BUFFER_SIZE 64

^

C:\Users\NEXUS\OneDrive\Documents\Arduino\sketch_mar29a\sketch_mar29a.ino:27:12: warning: type of ‘chlID’ does not match original declaration

extern int chlID;

^

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO\uartWIFIUNO.cpp:19:8: note: previously declared here

int8_t chlID; //client id(0-4)

^
Reply
Avinash
at
Permalink

Getting this error even after adding prescribed files to library
In file included from C:\Users\NEXUS\OneDrive\Documents\Arduino\sketch_mar29a\sketch_mar29a.ino:22:0:

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO/uartWIFIUNO.h:67:0: warning: “OPEN” redefined

#define OPEN 1

^

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO/uartWIFIUNO.h:55:0: note: this is the location of the previous definition

#define OPEN 0

^

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO/uartWIFIUNO.h:75:0: warning: “SERIAL_TX_BUFFER_SIZE” redefined

#define SERIAL_TX_BUFFER_SIZE 128

^

In file included from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Arduino.h:232:0,

from sketch\sketch_mar29a.ino.cpp:1:

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/HardwareSerial.h:46:0: note: this is the location of the previous definition

#define SERIAL_TX_BUFFER_SIZE 64

^

In file included from C:\Users\NEXUS\OneDrive\Documents\Arduino\sketch_mar29a\sketch_mar29a.ino:22:0:

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO/uartWIFIUNO.h:76:0: warning: “SERIAL_RX_BUFFER_SIZE” redefined

#define SERIAL_RX_BUFFER_SIZE 128

^

In file included from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Arduino.h:232:0,

from sketch\sketch_mar29a.ino.cpp:1:

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/HardwareSerial.h:53:0: note: this is the location of the previous definition

#define SERIAL_RX_BUFFER_SIZE 64

^

C:\Users\NEXUS\OneDrive\Documents\Arduino\sketch_mar29a\sketch_mar29a.ino:27:12: warning: type of ‘chlID’ does not match original declaration

extern int chlID;

^

C:\Program Files (x86)\Arduino\libraries\ESP8266UNO\uartWIFIUNO.cpp:19:8: note: previously declared here

int8_t chlID; //client id(0-4)

^
Reply
14core EditorPost author
at
Permalink

Try to change the library use ESP8266WiFi
Download ESP8266 WebServer | Zip
http://www.14core.com/wp-content/uploads/2017/03/ESP8266WiFi.zip
Reply
Fadhil Rahman
at
Permalink

Did we need to replace back the atmega328 after the set up of at-command??
Reply

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