I'm trying to control a DMX dimmer (eurolite ES-12 IEC DMX Switchback) through an Arduino Mega. In an earlier test, we were able to make one RGB DMX light run through the color spectrum. Now, a technician has installed this ES-12 dimmer pack with 12 1-channel DMX lights attached to it. The dimmer has some kind of built-in testing program and all the lights work.

The documentation on the dimmer is very sparse regarding the programming side of things. The dimmer is set to mode d--- and when the Arduino is running its program, a little green light flickers next to the d---, apparently responding to the signals it's receiving, like so: d---. Unfortunately, that the only light that responds.

I've tried using the DMXSimple library (the DMX is connected to pin 3), but even the example code (after correcting the brightness-- to ++) does not get any response -- none at all, not even the little green light. The only thing the little green light responds to is an analogWrite() on pin 3.

I'm guessing it's an addressing issue, but I don't know enough to fix it. As I understand it, the dimmer is seen as the controller and is sent a LOW on channel 0 as the Start Code (SC): http://www.dmx512-online.com/packt.html. The first light on the dimmer will then be channel 1, the second light channel 2, etc. (since, the technician tells me, they are 1-channel lights). Is this correct? Or is the dimmer its own universe that should be addressed in some other way?

  • What hardware are you using? You can't just connect an Arduino to a DMX device and have it work since DMX is built upon RS485. – user588 Aug 16 '16 at 18:03
  • I'm assuming the same DMX connector we used to run the tests on the RGB lights. I can't tell you the make and model, but the guy in charge of the hardware does this kind of thing for a living. Unfortunately, he's on vacation and he's built everything into a black box -- literally. I just do the software. – Elise van Looij Aug 16 '16 at 19:22
  • @Dan Nixon, I'll see if we can open the black box. – Elise van Looij Aug 17 '16 at 10:14

The light technician, Toby Peperkamp, came with the solution. I'm not sure exactly where he found the information, but apparently the protocol for non-RGB DMX lights requires that the lights be switched on to maximum (255) at the beginning of the connection. So I added that to the setUp() and all the lights started to respond.

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