Problems with Arduino and MAX/MSP (UDP communication)

Projects Interfacing w/ Software on the Computer
1

Hello everybody, I've created a new topic a couple of weeks ago in the Software section of the forum to ask about the problem I'm going to exhibit right now. I think that asking again here will be better since the problem is (probably) not about the Arduino and it's code but MAX/MSP.

This is a prntscreen of the MAX sketch I've made

Pretty simple stuff, it collects 3 bytes generated randomly by 3 different "drunk" functions and send them via UDP to the Arduino.

This is the Arduino code

#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>

#define localPort 7400

byte mac[] = {0x90, 0xA2, 0xDA, 0x0D, 0xE5};
IPAddress ip(192, 168, 1, 177);

EthernetUDP Udp;

int PACKET_SIZE = 0;

void setup()
{
Serial.begin(9600);
Ethernet.begin(mac, ip);
Udp.begin(localPort);
}

void loop()
{
PACKET_SIZE = Udp.parsePacket();
byte packetBuffer[PACKET_SIZE];

if (PACKET_SIZE > 0)
{
Udp.read(packetBuffer, PACKET_SIZE);

for (int i = 0; i <PACKET_SIZE; i++)
{
Serial.print(packetBuffer*);*

  • if (i < (PACKET_SIZE - 1))*
  • Serial.print(", ");*
  • else*
  • Serial.println(".");*
  • }*
  • }*
    }[/quote]
    Easy, it prints unto the serial monitor the data recevied via UDP by MAX/MSP. The problem is here...

    I should receive only 3 bytes, I can't understand why I get 28! Also - the correct ones - are the 20th, 24th and 28th. Seems like the others are something that comes from MAX/MSP but I don't know why and I don't know how to avoid this problem. I'm looking for some help, hope you'll enlighten me guys!
    Thanks for your tips!
    EDIT: I've just discovered something cool, the first 4 bytes (108, 105, 115, 116) compose the word "list", could this help?
2

Matt,

Have you tried posting this issue on the Cycling74 website?
There are more Max users there- and there is a special project just for using Max with the Arduino (Maxuino).
Chances are you'll get some good answers.

I've just started using Max myself- but haven't tried interfacing to the Arduino yet.

3

MaxMSP's netsend is really sending OSC encoded messages. These are more compact to send, but cause headache for manually encoding. But OSC is common enough that googling can either tell you:
how to get OSC into arduino
how to manually decode OSC into readable strings, and then you can repost your solution for the world to see

4

Matt:
Easy, it prints unto the serial monitor the data recevied via UDP by MAX/MSP. The problem is here...

909×384 14 KB

I should receive only 3 bytes, I can't understand why I get 28! Also -

Print out the value of PACKET_SIZE, that is what is controlling your loop