Using Arduino to convert DMX to Ethernet

Projects General Guidance
1

Hi,

I am currently thinking of a small side project of mine, which should be possible but I'm not entirely sure if Arduino is what I am looking for.

I am a deejay and because of that I have a lot of lights that I control using DMX. My fog machine, however, uses an ethernet port and a controller to change the input from outputting smoke to not outputting smoke.

I want to eliminate the fact that I am restricted to the length of my controller's wire, while there I have enough XLR cable to put my fogging machine 20 meters further.

The few problems I am facing before I am starting this project:
I do not know what input my fogmachine receives
My fog machine, a Martin Magnum 850, does not provide any technical documentation on what input causes what action. I can either wait for a response of their technical support helpdesk, but considering this information can not be found anywhere online, I guess it is information that is kept private for a reason. The controller I have right now, uses a Ethernet port for communicating with the fog machine. I need to be able to read every single pin of this remote to be able to find out what I should output using the Arduino, if this even is possible. How would I be able to read this output, and is it possible with the Arduino?

How do I output this information based to my fog machine
How do I send the correct input to my fogmachine once I have found out what input it requires? Can I simply set the signal for each pin on the Ethernet cable, or will this not work using the Arduino?

I am not that experienced with this all, and I am not even sure in what way the signal is sent. The optional remote has a timer, has lights that show if the fogmachine is currently ready, heated up and allows me to control the amount of fog it should output in percentages of the maximum it can. As far as I am aware, only 4 pins of the Ethernet cable can be controlled, the other ones can't, so then how is it able to send this much information using only 4 pins?

Once I have this all working, I hope I can link up a DMX module to my Arduino to read it's input and translate that to the Ethernet port, so I can finally control my fogging machine using my light controller.

2

I'm pretty sure that's NOT Ethernet, it just uses RJ-45 connectors and networking cables.

So really, all you need is a DMX receiver to "capture" a DMX command. Then you need to close a relay contact (or something like that) to turn-on the fog. That should be possible IF you can figure-out the connections and how the controller works.

As far as I am aware, only 4 pins of the Ethernet cable can be controlled, the other ones can't, so then how is it able to send this much information using only 4 pins?

I think it could be done... Power, Ground, one input to the controller for heating/ready, one output from the controller to activate the fog.

Do the heating & ready light's toggle? One or the other is always on? That can be done with one high/low data line if there are only two states.

Or, you could have power & ground plus serial transmit & receive lines.

Serial communication would be almost impossible to decipher if you don't know anything about the protocol.

You might be able to figure-out the wiring if you have a multimeter to measure the voltages under various conditions. If you can open-up the controller and/or the fog machine, that might make it easier to trace-down and identify the ground & power wires.

But be aware that if you start "hacking" your fog machine, injecting voltages and/or "shorting" wires with relays, you could kill it. There's always a risk with something like this and I wouldn't start unless you are prepared to replace it.

3

I have received the following information from Martin (JEM). This should definitely help me, but it makes me doubt if it really is a RJ45 connector. This schematic only has 6 pins, so I guess it is a phone wire (?). Either way, with a bit of experimenting, I should be able to get this to work, I'm quite sure.

I think now that I have the attached documents, I can say this project is feasable. I could create a DMX or Midi interface for this fogging machine. Nice!

01204024A.pdf (22.7 KB)

01204021B.pdf (26.3 KB)

4

Great! Shematics!!!!

This should definitely help me, but it makes me doubt if it really is a RJ45 connector. This schematic only has 6 pins, so I guess it is a phone wire (?).

That makes sense because you wouldn't want someone plugging the fog machine into a network and frying a network hub/switch or an Ethernet port on a computer. It's less likely that someone would try plugging into a phone line.

That would be an RJ11. Although technically, it might be a different RJ number if all 6 lines are used.

5

This is what technical support sent me as a follow up:

Hi Ruben,
The physical connector that connects the remote to the machine is RJ45 and is 8 pin (but only 5 pins are used).
At the remote end it is a 6 pin connector with only 5 pins used.
I have attached the schematic of the RJ45 socket so you can match the pins of the cable..
We can supply the cable (RJ45 one end – 6 pin other end) but not the connector.. P/N:11840101

I have a friend to help me out on this. I might order the Arduino soon, after I confirmed it works using my friend's Arduino. I ordered the exact same parts as listed on the schematics for the simple on/off controller to see if we can get it to work. All we have to do at first is replace the switch in the circuit with the Arduino and a transistor. Once that works, I want to try to regulate the voltage using the Arduino, however, I'm not entirely sure how I would do this, but I'm sure I'll learn along the way (like, where do I get this voltage from or where do I leave the excess, if there is any).

I've drawn a flowchart for the code that will process the DMX input and will regulate the voltage output. In terms of making the latter work I need some help along the way, though, I think this project is very feasable and easy to recreate for others.

Right now, the DMX module will use 3 channels. One for the output, one for the time it will output for and one for the time it will wait between outputting smoke. The timer will be done using code rather than hardware, so that makes it all a lot easier.

I might extend the project to add a seven segment display to show the input channel (when adjusting the dipswitches) and after an interval of a few seconds, show R, H or R+H (Ready, Heating, Ready + Heating). This should all fit on one block of 3 7-segment displays.

Document1.pdf (23.9 KB)

6

I made the simple remote using just a simple switch. Due to the lack of a proper diode, I used a LED, and I left out D2 and D3. It works fine...?

7

Cyberuben:
I made the simple remote using just a simple switch. Due to the lack of a proper diode, I used a LED, and I left out D2 and D3. It works fine...?

Hi CyberRuben,

Now, 6 years later, i want to do exactly the same for my martin 850 fog machine.
Can you please explain how you did it exactly? I only want to turn my fog machine on with a DMX signal, so it don't have to be the hard one.

Regards!
Don Wolters

8

Considering @CyberRuben is no longer a member of this forum, don't hold your breath waiting for an answer.

9

But maybe Someone Else knows what i mean, and can help me.

10

"But maybe Someone Else knows what i mean, and can help me."

Use the forum Google search function in the upper right of this page to search for the key words of your project. You will probably find many similar previous project discussions and code to get you started.