4 Channel DMX transceiver

The DMX IO Platform Module is a 4-channel DMX transceiver. In receive mode it can control up to four channels of low-current TTL (3.3v, e.g., for servos and small LEDs) or high-current (12v, e.g., lamps, relays, solenoids, stepper motor, etc.) output.  In transmit mode, it can issue commands to an entire DMX universe (512 channels).

Dual XLR-3 connectors allow the module to act as a receiver or transmitter (master) node in a DMX network and A 9-position DIP switch allows for address configuration without changing firmware.

The RS-485 hardware design allows for software switching between RX and TX modes allowing advanced programmers to experiment DMX receiver projects as well as serial- to-DMX applications.

What is DMX?

DMX is a serial protocol that runs over a RS-485 hardware link. It was originally designed to control lights (Chauvet has a bunch of cool DMX lights), but it is also used to control servos, LED's, stepper motors, relays, and other devices (Like a DMX Skeleton). It's an easy-to-use, robust protocol that allows for 1,500 Feet + cable runs using inexpensive cable. 

A DMX network  has 1 master device, and 1 or more slave devices.  512 control channels are available and many slave devices use more than one channel (e.g., a light might use 1 channel for pan, another for tilt).  Each channel can support 256 possible values, although some slave devices will combine 2 channels for 65,535 possible values.  Channel values can be changed about 44 times per second, or 44Hz. 

About This Module

You can add the DMX IO Module to the Propeller Platform, a protoboard, or even a breadboard. I'll talk about using it with a Parallax Propeller or Arduino at the end of this instructable.

The DMX IO module was designed by Jon Williams and is licensed under the MIT License.  He reviewed DMX (and this module) in his November Nuts n' Volts column, which you can read here (pdf). 

You can download the design file or buy the kit or a bare PCB from Gadget Gangster. Pre-assembled modules are also available.

Build time is about 45 minutes. Warm up your soldering iron and go to the next step!

Step 1 Using: Usage Ideas

While your iron is warming up, here are a few examples of the cool things you can do with DMX;

Christmas Display

There are a number of DMX dimmer/switch packs (here's one) that let you plug in a lamp or a strand of christmas lights (or anything else that can plug into the wall), turn it on or off, pulse, or dim it. The DMX IO module can issue commands through DMX to dimmer/switch packs or other DMX devices; stuff like Fog Machines, lasers, bubbles, or a snow machine.

Do A Light Show

Color your house

W Hotel In Boston

The DMX IO module can send commands to hundreds of slave devices, like these COLORdash Quad wash lights.

Control Servos and Animatronics

The DMX IO module can also be used to receive commands to control servos, pneumatics, or nearly any device you can think of - you get 12V from the screw-down terminals, and the board also has headers for 3V devices.

Just a few fun things that can be done.  Next, we'll start building the module, and at the end of this instructable, there's info on how to program it (don't worry, it's pretty easy). 

Comments

[andrew98]

Hi where can i find the pcb file for this ?

Thanks

[Racer_Rob]

This is a very interesting circuit. I only need the module to act as a slave to a DMX signal which I already have and turn on some LEDs. Does it still need to be connected to the Propeller Platform to achieve this? Or would it be possible to just reproduce the necessary elements of the Propeller Platform in isolation to achieve this?

[blinkyblinky]

How many leds did the Carol of the Bells movie require? Can I use this with the Propeller Platform usb? I love it.

[Musicmatters]

Can I get some guidance with how to wire this to an Aurdino UNO? Is there a schematic somewhere?

[Vadimk]

Just wanted to let you know that DMX standards specify a 5-pin xlr connector.
The reason for this is safety. 3-pin xlr connectors are standers for microphones and they are often fed with 48 volts.
Some manufactures use 3-pin connectors because there cheaper and the other 2 pins are rarely used.
The only other permissible connector is RJ-45 in a fixed instillation.

But otherwise nice instructable.

[Gadget Gangster]

Yeah - plugging your DMX hardware into a microphone jack is a bad thing.  But most of the hardware I found on the internet connected with an XLR3.

[Vadimk]

That's unfortunate. But use what works I suppose.

[Gadget Gangster]

I agree 100% - the real problem is the the hardware manufacturers.  By using XLR3 in their hardware, even if you wanted to use XLR5, you have to use an XLR5 - XLR3 adapter.  And that adapter can be plugged into a mic. 

I think the reason they went with XLR3 is that the cables are very, very cheap.  Sure, a mic cable isn't standards compliant, but it will work just fine for most setups, and you can get 50 foot cables for $10! 

[oneaze]

agree'd with the xlr3. but cable is important, audio xlr cable is a 80ohm , while dmx cable is 120ohm rated to allow data without hectic collision or devices going into a frenzy/shorting out.. xlr3 audio is used alot in industry sadly due to companys not wanting to spend a little extra for 5 pins the device will not use. And 80ohm cable can be used in short runs, but its not reccomended for long runs due to data packet errors and equipment malfunction which can be rather costly and dangerous..

[marc92]

This is pretty impressive, and I wonder how I could incorporate it into an existing theater lighting system.

Also, where do you have access to all those moving lights, and were they controlled using only this device?

[Gadget Gangster]

I wish I had all those lights!  The way DMX is structured, there's one master device and multiple slaves.  The DMX IO can act as a master and send out commands to to 512 channels (aka, many devices).  Each of the lights have a power plug, and an XLR connector to receive commands.  You could program a sequence, or issue commands in real-time. 

It can also act as a slave and receive commands from a master device.  As a slave, it it has terminals and servo pin headers  for up to 4 devices.  So for something like the halloween setup, you might use one DMX IO per skeleton.