Getting started with DMX512 on the Uno

Projects Networking, Protocols, and Devices
1

I have started a project where I hope to control a stepper motor by accepting a DMX512 signal (normally used for controlling theatrical lights). The stepper will use a very simple controller that requires the Arduino to signal each coil individually. I could change to a more complex one that accepts plus and direction signals from Arduino.

I have the following equipment,

  1. Arduino Uno
  2. DMX512 Shield [I.e. a rs485 interface]
    $12 from www.oddwires.com/rs485-dmx-shield/
  3. Stepper with driver board
    $3 from www.oddwires.com/stepper-motor-and-driver-board-uln2003-for-arduino/

I have read the following resources, but am still quite confused;
A) The Arduino DMX playground page; Arduino Playground - DMX
B) Searching this forum.
C) http://www.maxwellrosspierson.com/2009/03/20/receive-dmx-512-with-an-arduino/
D) Arduino Playground - HomePage

The C) resource seems to point me to a collection of sketches, and apparently includes a library. But what I thought was the library only has one file with a .cpp extension, and does not have the proper extensions to be a library. Also, the sketches themselves are the older .pde extension, but I understand that simply opening and then saving them in the current Arduino IDE program will change them to the current format.

The D) resource seems to be the simplest to implement. And rather than a library it has code that gets pasted into your sketch. However, apparently the code must be manually edited for each type of processor. They say, "names of the registers and the name of the ISR vector used may differ." But, I have no experience with these things, so their directions don't really help me.

Any further ideas about how to accept DMX data as simply as possible for this Arduino beginner?

-Joe

2

Hi,

I see there have been no helpful replies to your post. I wish I could provide one but I have been going nuts for the past 6 hours with either contradictory or incomplete information despite a lot of web searching.
I am sure it cannot be that hard, but when sketches do not state which Arduino or which version of the Arduino software they work on, then finding a foothold is a nightmare.
If you ever did sort out an answer, I would be delighted to learn how.

Cheers
Simon

3

I eventually gave up on the DMX shield. It required more understanding of programming the Arduino than I really wanted to get into, and I was scared off by other experiences similar to yours.

I did end up purchasing the $25, DMX to Serial Converter v.1 from www.chromationsystems.com This seemed like a MUCH better solution, and a good price for it. Though, at the moment they are out of stock.. Here is the description from their web site;

" This device reads a DMX-512 signal and grabs a variable amount of channel data values and sends them at 57200 baud to an external device when a new data packet is requested. This allows any microcontroller(PIC, Arduino, ATMel, ect.) with TTL serial communication to accept DMX-512 data without the overhead of decoding the DMX signal and grabbing the necessary data values."

For me, I haven't even opened the package, because the need for it has gone away. So it is now on the "back burner" of my project list.

Joe Dunfee