viorelracoviteanu
Published © GPL3+

Monitoring and control over the web with 2 Arduino and Ether

Two Arduino talk to each other over the local area network

BeginnerFull instructions provided5 hours1,134
Monitoring and control over the web with 2 Arduino and Ether

Things used in this project

Hardware components

Arduino Nano R3
Arduino Nano R3
×2
Ethernet Cable, Cat6a
Ethernet Cable, Cat6a
×2
ENC28J60 Ethernet Shield
×2
Arduino 4 Relays Shield
Arduino 4 Relays Shield
×1
PTS 645 Series Switch
C&K Switches PTS 645 Series Switch
×4

Software apps and online services

Arduino IDE
Arduino IDE

Hand tools and fabrication machines

Soldering iron (generic)
Soldering iron (generic)
Multitool, Screwdriver
Multitool, Screwdriver
Mastech MS8217 Autorange Digital Multimeter
Digilent Mastech MS8217 Autorange Digital Multimeter

Story

Read more

Custom parts and enclosures

Electric diagram

Electric diagram

Schematics

Electric diagram

A simple schematic of how it works.

Code

Server

Arduino
This is the Server, it reads the inputs and puts up a web-page
/*  This code outputs a web-page with pin status in the form of 0 or 1, like: 00100010
 *  It acts as a web server.
 *  I chose to monitor Analog pins A0-A5 because most of the digital pins are taken over by the Ethernet shield
 *  =========================================================
 *  Viorel Racoviteannu /
 *  https://www.youtube.com/@Racov
 *  https://racov.ro
 *  YO3RAK@gmail.com
 *  =========================================================
 *  I cannot take any responsibility for missuse of this code or any kind of damage it may occur from using this code.
 *  =========================================================
 ---Version history---
 *  Jul. 2023 - first try :)
*/

// UIPEthernet library is used for Arduino Nano Ethernet Shiel
// It is not needed if you are using Arduino UNO/Duemilanove/Mega/etc.
#include <UIPEthernet.h> // Used for Ethernet

// **** ETHERNET SETTING ****
// byte mac[] = { 0x90, 0xA2, 0xDA, 0x0D, 0x78, 0xEE };
byte mac[] = {0x01,0x02,0x03,0x04,0x05,0x06};
IPAddress ip(192, 168, 1, 115);
EthernetServer server(80);

char Pin[9]="";        // string to keep the pin status
char WebWrite[40]="";  // string to be displayed on the web
int val;

void setup() {
  // pin declaration
  pinMode(A0, INPUT);
  pinMode(A1, INPUT);
  pinMode(A2, INPUT);
  pinMode(A3, INPUT);
  pinMode(A4, INPUT);
  pinMode(A5, INPUT);

  Serial.begin(9600);
 // display splash screen:
  Serial.println("Viorel Racoviteannu / Jul. 2023");
  Serial.println("https://www.youtube.com/@Racov");
  Serial.println("https://racov.ro");
  Serial.println("YO3RAK@gmail.com");
  Serial.println("This code creates a web-page with pin status in the form of 0 or 1, like: 00100010");
  Serial.println("I chose to monitor Analog pins A0-A5 because most of the digital pins are taken over by the Ethernet shield \n\r");
 // start the Ethernet connection and the server:
  Ethernet.begin(mac, ip);
  delay(1000);
  server.begin();
  Serial.print("local IP: ");
  Serial.println(Ethernet.localIP());
  Serial.println(" \n\r");
}

void loop() {
  // listen for incoming clients
  EthernetClient client = server.available();

  if (client) 
  {  
    Serial.print("New Connection. ");
    Serial.print("Sending-> ");
    Serial.print(Pin);
    // an http request ends with a blank line
    boolean currentLineIsBlank = true;

    while (client.connected()) 
    {
      // read the status of the pins and create the string
      val = digitalRead(A0);
      if(val == 0 ) { Pin[0] = '0'; }
        else { Pin[0] = '1'; }
      val = digitalRead(A1);
      if(val == 0 ) { Pin[1] = '0'; }
        else { Pin[1] = '1'; }
      val = digitalRead(A2);
      if(val == 0 ) { Pin[2] = '0'; }
        else { Pin[2] = '1'; }
      val = digitalRead(A3);
      if(val == 0 ) { Pin[3] = '0'; }
        else { Pin[3] = '1'; }
      val = digitalRead(A4);
      if(val == 0 ) { Pin[4] = '0'; }
        else { Pin[4] = '1'; }
      val = digitalRead(A5);
      if(val == 0 ) { Pin[5] = '0'; }
        else { Pin[5] = '1'; }
      // creating the line with pin values
      strcpy (WebWrite ,"<body><h3>");
      strcat (WebWrite , Pin);
      strcat (WebWrite , "</h3></body>");
      if (client.available()) 
      {
        char c = client.read();

        // if you've gotten to the end of the line (received a newline
        // character) and the line is blank, the http request has ended,
        // so you can send a reply
        if (c == '\n' && currentLineIsBlank) 
        {
          client.print("<html><title>Web Control</title>");
          client.println(WebWrite);
          client.println("<body><h3>A0=>A5</h3></body>");
          client.println("<body><h3>Viorel Racoviteanu 2023</h3></body>");
          client.println("<body><h3>https://racov.ro || https://www.youtube.com/@Racov</h3></body>");
          break;
        }

        if (c == '\n') {
          // you're starting a new line
          currentLineIsBlank = true;
        }
        else if (c != '\r') 
        {
          // you've gotten a character on the current line
          currentLineIsBlank = false;
        }
      }
    }

    // give the web browser time to receive the data
    delay(100);

    // close the connection:
    client.stop();
    Serial.println(" <- Disconnected");
  }
}

Client

Arduino
This is the client, it reads the web-page and activates the outputs.
/*  This code reads a web-page with pin status in the form of 0 or 1, like: 00100010
 *  It acts as a web client and activates its coresponding pins. See the server code...
 *  I chose to monitor Analog pins A0-A5 because most of the digital pins are taken over by the Ethernet shield
 *  =========================================================
 *  Viorel Racoviteannu /
 *  https://www.youtube.com/@Racov
 *  https://racov.ro
 *  YO3RAK@gmail.com
 *  =========================================================
 *  I cannot take any responsibility for missuse of this code or any kind of damage it may occur from using this code.
 *  =========================================================
 *  ---Version history---
 *  Jul. 2023 - first try :)
*/

// UIPEthernet library is used for Arduino Nano Ethernet Shiel
// It is not needed if you are using Arduino UNO/Duemilanove/Mega/etc.
#include <UIPEthernet.h>

// **** ETHERNET SETTING ****

byte mac[6] = {0x01,0x02,0x03,0x04,0x05,0x07};
IPAddress ip(192, 168, 1, 116);
EthernetClient client;
signed long next;

void setup() {
  // pin declaration
  pinMode(A0, OUTPUT);
  pinMode(A1, OUTPUT);
  pinMode(A2, OUTPUT);
  pinMode(A3, OUTPUT);
  pinMode(A4, OUTPUT);
  pinMode(A5, OUTPUT);

  Serial.begin(9600);
// display splash screen:
  Serial.println("Viorel Racoviteannu / Jul. 2023");
  Serial.println("https://www.youtube.com/@Racov");
  Serial.println("https://racov.ro");
  Serial.println("YO3RAK@gmail.com");
  Serial.println("Reads a web-page with pin status in the form of 0 or 1, like: 001001");
  Serial.println("It acts as a web client and activates its coresponding pins");
  Serial.println("I chose to monitor Analog pins A0-A5 because most of the digital pins are taken over by the Ethernet shield \n\r");
  digitalWrite(A0, LOW);                  // trigger some sort of alarm
  digitalWrite(A1, LOW);                  // for COMM FAIL
// start the Ethernet connection
  Ethernet.begin(mac, ip);
  delay(1000);
  Serial.print("local IP: ");
  Serial.println(Ethernet.localIP());
  Serial.println("");

  next = 0;
}

void loop() {

  if (((signed long)(millis() - next)) > 0)
    {
      next = millis() + 5000;
      Serial.print("Connecting to server ->");
      if (client.connect(IPAddress(192, 168, 1, 115),80))
        {
          Serial.print("-> Connected. ");
          client.println("GET HTTP/1.1");
          client.println("Connection: close");
          client.println();
          while(client.available()==0)
            {
              if (next - millis() < 0)
                goto close;
            }
          int size;
          while((size = client.available()) > 0)
            {
              String result = client.readString();
              Serial.print("Received-> ");
              //Serial.print(result);               // print the entire message for debuging
              for (int i = 42; i <= 47; i++) {      // print only the important bits (A0->A5)
                Serial.print(result.charAt(i));
              }
              // extracting each bit and activating the corresponding pin
              char val1; int val2;
              val1 = result.charAt(42);             // extract the pin value of the (remote) server
                val2 = val1 - '0';                  // conversion from 'char' to 'int'
                digitalWrite(A0, val2);             // activate the (local) client respective pin
              val1 = result.charAt(43);
                val2 = val1 - '0';
                digitalWrite(A1, val2);
              val1 = result.charAt(44);
                val2 = val1 - '0';
                digitalWrite(A2, val2);
              val1 = result.charAt(45);
                val2 = val1 - '0';
                digitalWrite(A3, val2);
              val1 = result.charAt(46);
                val2 = val1 - '0';
                digitalWrite(A4, val2);
              val1 = result.charAt(47);
                val2 = val1 - '0';
                digitalWrite(A5, val2);
            }

          close:
          //disconnect client
          Serial.println(" <-Disconnected.");
          client.stop();
        }
      else {
        Serial.println(" <-Connection failed.");
      }
    }
}

Credits

viorelracoviteanu

viorelracoviteanu

5 projects • 52 followers

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