通过UDP从Arduino以太网发送POT值

Question

I have an Arduino ethernet which I am using to read POT values on a simulator, I want to then send these values to the computer with the simulator software on it so they can be input to the game.

I doing this via UDP as the guy who wrote the program to integrate it with the game said it would be easier this way and that recording data from the the controls (for research purposes) would also be easier. Regardless of whether this is true, I can not change this.

I am currently trying to write some code to send values read by a POT to some processing code which then displays this value. This is just as an intermediate step before I try and integrate this code with the game etc. I am a beginner with regards to programming in this respect, I have just been thrown in at the deep end here. While I can program, this has only really been making mathematical programs with matlab.

I have tried to modify some code given in examples and have ended up with the following but its not working:

Aruino Code:

#include // needed for Arduino versions later than 0018 #include #include // UDP library from: bjoern@cs.stanford.edu 12/30/2008

// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
  0x90, 0xA2, 0xDA, 0x0F, 0xC6, 0x1F
};
IPAddress ip(192, 168, 0, 177);

unsigned int localPort = 8888;      // local port to listen on

// buffers for receiving and sending data
char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to hold incoming  packet,
char  ReplyBuffer[] = "acknowledged";       // a string to send back

// An EthernetUDP instance to let us send and receive packets over UDP
EthernetUDP Udp;

int potPin = 2;    // select the input pin for the potentiometer
int val = 0;       // variable to store the value coming from the sensor
int mapped = 0;

void setup() {

 // start the Ethernet and UDP:

  Ethernet.begin(mac,ip);

  Udp.begin(localPort);

}



void loop() {

  val = analogRead(potPin);  // read the value from the sensor
  mapped = map(val, 0, 1023, 0, 5000);

  Serial.print(analogRead(potPin));
  Serial.print(mapped);    
  delay (400);

   Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());

    Udp.write(mapped);

   Udp.endPacket();

}

Processing code:

 import hypermedia.net.*;

 UDP udp;  // define the UDP object
 String value = "0";

 void setup() {
 size(480,640);
 background(0);
 smooth();
 udp = new UDP( this, 3000 );  // create a new datagram connection on port 6000
 udp.log( true );     // <-- printout the connection activity
 udp.listen( true );           // and wait for incoming message
 }

 void receive( byte[] data ) {       // <-- default handler
 //void receive( byte[] data, String ip, int port ) {  // <-- extended handler

  value=new String(data);
  println(value);

 }

 void draw()
  {
  fill(50);
  if (value != "0") {
  text(value, 10, 10, 70, 80); 
  }

 }

Note: There maybe be some uneccesary lines in there which I have failed to delete from the code which I modified. Also the mapped value of the analogue read is just as Im not sure what range of values the game will want to receive as of yet.

Thanks for any help!

Answer 1

I can't say exactly what is going wrong, but here are some things that stuck out in your code. The Arduino code sends the message out on the UDP.remotePort port. From what I read elsewhere it looks like this would only be set by receiving a message, so maybe try hard-coding this along with the remote IP to ensure it is set correctly.

Also I would eliminate one of your problems for the time being and just use a UDP terminal. I have used Hercules before on Windows http://www.hw-group.com/products/hercules/index_en.html . This will let you just focus on the Arduino code and it should let you see everything that is going on. Wireshark would be another more complicated option that will really let you see exactly what you are sending out on the network.