Introduction

This post will be shown an application of using a UDP connection between PC and M-DUINO. The aim is to enable and disable Inputs and Outputs with a message. 

Requirements

M-Duino family

Ethernet2 library provided by Industrial Shields. Downloading our boards you will have this library. In this link you can read the blog where it explains how to get it. 

Application

First of all, we have to create your local network to work better without disturbing anyone. Here you have an example diagram:

Our M-Duino has be:ad:be:ef:fe:ed as address mac, 10.20.1.2 as IP and 8888 as local port. The steps to follow are:

    - Configurate our M-Duino with these parameters.

    - Waiting for a message to be received.

    - Transmit confirmation message.

    - Analyze the message.    

Reception

Messages Protocol

There are different ways to send the messages, it's up to you, but in our case we have used the next protocol:

ON:QX.X to enable a relay

OFF:QX.X to disable a relay

#include <Ethernet2.h>
#include <EthernetUdp2.h>

byte mac[] = { 0xBE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(10, 20, 1, 2);
uint16_t rx_udp_port = 8888; // local port to listen on
uint16_t tx_udp_port = 5566;

char packetBuffer[UDP_TX_PACKET_MAX_SIZE];
char *replyBuffer = "ACK\n"; // acknoleged;

EthernetUDP Udp;

void setup() {
  // start Ethernet
  Serial.begin(9600);
  Ethernet.begin(mac, ip);
  Serial.println(Ethernet.localIP());
  // start UDP
  Udp.begin(rx_udp_port);  
}

static void filter_message(char *packet){
  char zone, pin;
  
  switch(packet[1]){
    case 'N': // Filter by N -> ON 
      if (packet[3] == 'Q'){ // Filter by Q -> Digital pin 
        zone = packet[4];
        pin = packet[6];
        if (zone == '0'){ // Filter by zone 0, 1 or 2 
          switch(pin){ // Filter by pin 0, 1, 2, 3, 4, 5, 6 or 7
            case '0':
              digitalWrite(Q0_0, HIGH);
              break;
            case '1':
              digitalWrite(Q0_1, HIGH);
              break;
            case '2':
              digitalWrite(Q0_2, HIGH);
              break;
            case '3':
              digitalWrite(Q0_3, HIGH);
              break;
            case '4':
              digitalWrite(Q0_4, HIGH);
              break;
            case '5':
              digitalWrite(Q0_5, HIGH);
              break;
            case '6':
              digitalWrite(Q0_6, HIGH);
              break;
            case '7':
              digitalWrite(Q0_7, HIGH);
              break;              
            }
          }/* If it had more zones
          else if (zone == '1'){
            switch(pin){
            case '1':
              digitalWrite(Q1_0, HIGH);
              break;
            case '2':
              digitalWrite(Q1_1, HIGH);
              break;
            case '3':
              digitalWrite(Q1_2, HIGH);
              break;
             .
             .
             .
            }
          }
          else if (zone == '2'){
            switch(pin){
            case '1':
              digitalWrite(Q2_0, HIGH);
              break;
            case '2':
              digitalWrite(Q2_1, HIGH);
              break;
            case '3':
              digitalWrite(Q2_2, HIGH);
              break;
             .
             .
             .
            }
          }*/
          Serial.print("Digital ");
          Serial.print(zone);
          Serial.print(".");
          Serial.print(pin);
          Serial.println(" activated");
      }
      break;
       
    case 'F': // Filter by F -> OFF
      if (packet[4] == 'Q'){ // some relay I/O
        zone = packet[5];
        pin = packet[7];
        if (zone == '0'){
          switch(pin){
            case '0':
              digitalWrite(Q0_0, LOW);
              break;
            case '1':
              digitalWrite(Q0_1, LOW);
              break;
            case '2':
              digitalWrite(Q0_2, LOW);
              break;
            case '3':
              digitalWrite(Q0_3, LOW);
              break;
            case '4':
              digitalWrite(Q0_4, LOW);
              break;
            case '5':
              digitalWrite(Q0_5, LOW);
              break;
            case '6':
              digitalWrite(Q0_6, LOW);
              break;
            case '7':
              digitalWrite(Q0_7, LOW);
              break;
            }
          }/*
          else if (zone == '1'){
            switch(pin){
            case '1':
              digitalWrite(Q1_0, LOW);
              break;
            case '2':
              digitalWrite(Q1_1, LOW);
              break;
            case '3':
              digitalWrite(Q1_2, LOW);
              break;
             .
             .
             .
            }
          }
          else if (zone == '2'){
            switch(pin){
            case '1':
              digitalWrite(Q2_0, LOW);
              break;
            case '2':
              digitalWrite(Q2_1, LOW);
              break;
            case '3':
              digitalWrite(Q2_2, LOW);
              break;
             .
             .
             .
            }
          }*/
          Serial.print("Digital ");
          Serial.print(zone);
          Serial.print(".");
          Serial.print(pin);
          Serial.println(" desactivated");
      } 
      break;
  }
}

void loop() {
  int packetSize = Udp.parsePacket();
  if (packetSize) {
    // read the packet into packetBufffer
    Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);  
    // send a reply to the IP address and port that sent us the packet we received
    Udp.beginPacket(Udp.remoteIP(), tx_udp_port);
    Udp.write(replyBuffer);
    Udp.endPacket();
    filter_message(packetBuffer);
  }
  delay(10);
}

Demonstration

In this demonstration we send four messages from the PC (IP : 10.20.1.1) to the M-Duino (IP : 10.20.1.2)

Message 1: Enable Digital pin 0.1

Message 2: Enable Digital pin 0.5

Message 3: Disable Digital pin 0.1

Message 4: Disable Digital pin 0.5 

The following image shows this

Video