Go Down

Topic: artnet to dmx project. memory issues? (Read 2403 times) previous topic - next topic


the project:
my goal is to use a arduino UNO to make a artnet node. this will convert artnet to dmx.

hardware: Arduino UNO with a ethernet shield and a proto shield with sn75176 ic connected to digital pin 3 for dmx out.

IDE: arduino 1.0

libraries used: DmxSimple, SPI, Ethernet, EthernetUdp.
Link to DmxSimple Library: http://code.google.com/p/tinkerit/wiki/DmxSimple

The Dmx Simple Library is modified to work with arduino 1.0

The code is 99% made by Christoph Guillermet
original code can be downloaded from here:

I have added the dmx out feature to the code and adapted it for Arduino 1.0.

to my problem! This code sort of works. It is working for about 10 seconds of changeing values and then i freezes.
Im guessing this has to do with some sort of memmorie issue. im also guessing it has to do with the DmxSimple library bacuse the original sketch does not have this issues.

Things i have tried: Instead of receiving all of the 512 dmx channels i have tried to limit this to just one. but same thing happens but after ca 25 seconds instead of 10.

so does some one have clue how i can solve this ?

The Code
Code: [Select]


This SCRIPT allows you to use arduino with ethernet shield or wifi shield and recieve artnet data. Up to you to use channels as you want.

If you have implemented ameliorations to this sketch, please, contribute by sending back modifications, ameliorations, derivative sketch. It will be a pleasure
to let them accessible to community

For VVVV patchers, please think to put a mainloop node in your patch: minimum frame rate is 40fps with bulbs. But do not go too much higher ( max 100 fps).

This sketch is part of white cat lighting board suite: /http://www.le-chat-noir-numerique.fr 
wich is sending data to many different types of devices, and includes a direct communication in serial also with arduino likes devices
you may find whitecat interresting because its theatre based logic ( cuelist and automations) AND live oriented ( masters, midi, etc)

(c)Christoph Guillermet

#include <DmxSimple.h>
#include <SPI.h>         // needed for Arduino versions later than 0018
#include <Ethernet.h>
#include <EthernetUdp.h>          // UDP library from: bjoern@cs.stanford.edu 12/30/2008
#define short_get_high_byte(x) ((HIGH_BYTE & x) >> 8)
#define short_get_low_byte(x)  (LOW_BYTE & x)
#define bytes_to_short(h,l) ( ((h << 8) & 0xff00) | (l & 0x00FF) );

//MAC and IP of the ethernet shield
//MAC adress of the ethershield is stamped down the shield
//to translate it from hexa decimal to decimal, use: http://www.frankdevelopper.com/outils/convertisseur.php
byte mac[] = {  144, 162, 218, 00, 16, 96  };//the mac adress of ethernet shield or uno shield board
IPAddress  ip(192,168,0,60 );// the IP adress of your device, that should be in same universe of the network you are using, here: 192.168.1.x

// the next two variables are set when a packet is received
byte remoteIp[4];        // holds received packet's originating IP
unsigned int remotePort; // holds received packet's originating port

//customisation: edit this if you want for example read and copy only 4 or 6 channels from channel 12 or 48 or whatever.
const int number_of_channels=512; //512 for 512 channels
const int channel_position=1; // 1 if you want to read from channel 1

// buffers

char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to store incoming data
byte buffer_dmx[number_of_channels+channel_position]; //buffer to store filetered DMX data

// art net parameters
unsigned int localPort = 6454;      // artnet UDP port is by default 6454
const int art_net_header_size=17;
const int max_packet_size=576;
char ArtNetHead[8]="Art-Net";
char OpHbyteReceive=0;
char OpLbyteReceive=0;
short is_artnet_version_1=0;
short is_artnet_version_2=0;
short seq_artnet=0;
short artnet_physical=0;
short incoming_universe=0;
boolean is_opcode_is_dmx=0;
boolean is_opcode_is_artpoll=0;
boolean match_artnet=1;
short Opcode=0;
EthernetUDP Udp;

void setup() {
  //déclaration des ports PWM
  //ici une diode pour test
  pinMode(3, OUTPUT);  //check with leds + resistance in pwm, this will not work with pins 10 and 11, used by RJ45 shield

  // démarrage ethernet et serveur UDP


void loop() {
   int packetSize = Udp.parsePacket();
  if( packetSize>art_net_header_size && packetSize<=max_packet_size)//check size to avoid unneeded checks
    //read header
     match_artnet=1;//valeur de stockage
     for (int i=0;i<7;i++)
      {match_artnet=0;break;}//if not corresponding, this is not an artnet packet, so we stop reading
     if (match_artnet==1)//if its an artnet header
          /*artnet protocole revision, not really needed
          /*sequence of data, to avoid lost packets on routeurs
          /*physical port of  dmx N°
     //operator code enables to know wich type of message Art-Net it is
     if(Opcode==0x5000)//if opcode is DMX type
     else if(Opcode==0x2000)//if opcode is artpoll
     //( we should normally reply to it, giving ip adress of the device)

     if(  is_opcode_is_dmx=1)//if its DMX data we will read it now
     //if you need to filter DMX universes, uncomment next line to have the universe rceived
     //incoming_universe= bytes_to_short(packetBuffer[15],packetBuffer[14])
     //getting data from a channel position, on a precise amount of channels, this to avoid to much operation if you need only 4 channels for example
     for(int i=channel_position-1;i< number_of_channels;i++)//channel position
     buffer_dmx[i]= byte(packetBuffer[i+17]);

     }//end of sniffing



Code: [Select]
byte buffer_dmx[number_of_channels+channel_position]; //buffer to store filetered DMX data
There's a 1/4 of your memory, if you have other than a Mega.

Things i have tried: Instead of receiving all of the 512 dmx channels i have tried to limit this to just one. but same thing happens but after ca 25 seconds instead of 10.

Doesn't really look like that...



Things i have tried: Instead of receiving all of the 512 dmx channels i have tried to limit this to just one. but same thing happens but after ca 25 seconds instead of 10.
Doesn't really look like that...

To change the amount of channels, i have used this part of the code:

Code: [Select]
//customisation: edit this if you want for example read and copy only 4 or 6 channels from channel 12 or 48 or whatever.
const int number_of_channels=512; //512 for 512 channels

and i dont think it is the part you suggest, that i have problems in beacuse that is from the original artnet reciving code and that one works.


I get this problem too and it seems like maybe the w5100 buffer is getting too full and not clearing properly (uneducated guess)

I get the same problem when using the UDPsendReceiveString sketch that comes with the ethernet library.  If I send udp packets one at a time the arduino reports back correctly but if I send a constant stream of artnet data (I think 538 bytes per packet and usually at a rate of 40-60 pps) the arduino freezes (or probably just the w5100 freezes)

As artnet is a realtime communication all I need is to read one packet from the buffer every time the arduino's loop passes round, therefore I have no use for buffered packets apart from the one I want to read that cycle.

I tried flushing with Udp.flush but that didn't seem to work.

It's spinning out with even smaller packets too.

I've tried 2 units.  And I don't know if it's just me but it seems to get worse over time.

I had the same problem, reported here

what is the size of your UDP_TX_PACKET_MAX_SIZE
Its defined in the Udp.h or EthernetUdp.h , depending on which arduino version you are using.
I am asking, because sometime people tinker with this value.

Try to change your code from
char packetBuffer[UDP_TX_PACKET_MAX_SIZE];
char packetBuffer[512];
// packetBuffer[512] is working for me on Uno, but you should aim using the value originally which was 2048


I guys, I did not understand if you resolved the problems, did you ??

And where I can find assembly instructions  ??

Thank You !!


The fix for me was to use an arduino mega

Sep 04, 2012, 11:38 am Last Edit: Sep 04, 2012, 11:40 am by rafaelmizrahi Reason: 1
indeed mrboni. I also previously switched to Mega+Ethernet shield and my program started to work properly.
but, than, I changed the UDP_PACKET_MAX_SIZE from 2048 to 576, which is artnet max packet size , and the program is now running properly using Uno+Ethernet
(sorry for not posting the code. the development is still in progress.)


Hi mrboni, i'm sorry but I'm not so expert about ARDUINO, can you explain me more what you've done... I'm trying to build something like this:

proximity sensor-->-->control lighting software-->-->lighting fixtures

I have a software, I have a dmx OUT hardware, but I need to understand how to make comunicate the sensor with a software.

I know that I have to convert the sensor signal into dmx; I think that the right way is to use an artnet to dmx device, is that you use right for this ?

if yes, can you tell me exactly what kind of hardware I need and how to assemble it ... than I will think about the ARDUINO code...


Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131