14 replies to this topic

[John]

I've played around with microcontollers here and there, but now I have a project that I must work out. I'm trying to figure out the best way to tackle this new project. What my goal is to control a high powered LED and stepper motor using DMX-512. I'm not sure how to approach this but I could use some help getting pointed in the right direction. Is the netduino a good choice or is there something that would be better.

[Chris Seto]

I've played around with microcontollers here and there, but now I have a project that I must work out. I'm trying to figure out the best way to tackle this new project. What my goal is to control a high powered LED and stepper motor using DMX-512. I'm not sure how to approach this but I could use some help getting pointed in the right direction. Is the netduino a good choice or is there something that would be better.

How high power of an LED are we talking?

After googing abit, it looks like DMX-512 is a communications standard used by stage lights, so I'm guessing we are talking about a "very bright" LED.

The first step would be building what you want to control. Do you have a specific model of stagelight you are controlling, or did you want to make it yourself?

[Szymon]

I've played around with microcontollers here and there, but now I have a project that I must work out. I'm trying to figure out the best way to tackle this new project. What my goal is to control a high powered LED and stepper motor using DMX-512. I'm not sure how to approach this but I could use some help getting pointed in the right direction. Is the netduino a good choice or is there something that would be better.

This sounds similar to one of the projects I want to implement myself. Could you provide more detail on what you are going to build?

-Szymon

[John]

It's not going to be a stage lighting like you normally think of. It's actually going to be a fountain (http://mad-laborator...-stepper-motor/). I've been working on this project for too long, and am finally getting to the control part of it. I really want to be able to sync up the music and the fountain to "make it dance" so to speak. Ultimately I'm planning on getting a whole bunch of these installed in my yard. But let's not get ahead of ourselves here. I understand that DMX basically sends out an address and a value. If the slave device has been called then it looks at the value and act accordingly. Can a dmx device control two different devices? i.e. Can the netduino control the stepper and LED at the same time?

[Chris Seto]

I think you may find a lot of answers to your DMX questions right on Wikipedia, here: http://en.wikipedia.org/wiki/DMX512 Usually, embedded development starts with reading the documentation behind the technology you want to use. In this case, you need to read through the DMX docs to find out about it and see what you need to do when you start actually developing.

[Chris Walker]

Can a dmx device control two different devices? i.e. Can the netduino control the stepper and LED at the same time?

Hi John, sounds like a cool project.

I'm not knowledgeable about the particulars of DMX, but here are a few questions to get started down the path:
Can you drive your DMX gear via a provided communication standards (UART, SPI, I2C) using 3.3V signals?
* If yes, then you'll probably just need some C# driver code.
* If no, then you'll either need:
* an accessory which uses one of the provided communication standards to drive DMX...and some C# driver code for it.
* a low-level driver (just compile it into the Netduino firmware) which provides DMX support

Let's see what we can figure out together as a community here...

[And thanks Chris Seto for the link to the DMX docs; great starting info there.]

Chris

[John]

Thanks everyone! I didn't realize that they actually have a document stating all the protocol for DMX 512. I went ahead and bought an electronic copy. Hopefully, I can understand it.

[Jay Sheldon]

Have you made any further progress on this project? I'm interested in building animated Christmas lights (to music) using the DMX-512 system.

[Mich]

Hi, i would also be very interested in this topic! Did anybody find a way to connect netduino to dmx devices? The only thing i found was a arduino shield for dmx, but i'm completly new to microcontrollers so i can not "port" the information to netduino. Best wishes, Mich Sorry, forgotten the link to the shield: http://www.arduino.c...nd/Learning/DMX

Edited by Mich, 24 January 2011 - 08:16 PM.

[michielvd]

I'm also trying to make a dmx controller with the netduino. Have you found a way of sending the DMX packets jet? I can't find a timer which works with microseconds because you need to hold each bit for 4µs. Has anybody any ideas?

[Tecchie]

I can't find a timer which works with microseconds because you need to hold each bit for 4µs. Has anybody any ideas?

You don't have to resort to manually bitbanging the DMX data as it's just a serial protocol, so you can use one of the UARTs of the netduino. Just look at the example i posted in the Showcase section.

[michielvd]

You don't have to resort to manually bitbanging the DMX data as it's just a serial protocol, so you can use one of the UARTs of the netduino. Just look at the example i posted in the Showcase section.

hey thanks for this code I thought about doing the same thing but didn't find much information on the SerialPort class in the micro framework. Mostly the thing with the stop-bits. I thrust that this generates the start-bit to.

I still have one question about the code. Why do you call Thread.Sleep(40)?

[Tecchie]

Why do you call Thread.Sleep(40)?

The SerialPort.Write command does not block until all data is actually sent. So i have to wait or otherwise the break generation of the next round collides with sending of data of the last round.
Of course to get highest possible refresh rate, one would have to resort to a more sophisticated approach, maybe waiting until BytesToSend is zero.

[Sebbasstt]

Hi there is there a sample code for a DMX512 receiver? I need a code base for a project. thank you

[OldNo7]

Hi there is there a sample code for a DMX512 receiver?

I need a code base for a project.

thank you

Did you ever find any sample code for a DMX receiver? I'd like to add this to one of my projects also.