Thread: Easy DMX relays with Medusa DMX

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Hi everyone,

I finally got to hook up and play with a relay module I picked up a little while ago. This should be a nice clean solution, for those looking for DMX relay control.

The module is from mdfly.com. It has (8) 10 Amp SPDT relays (has both normally open, and normally closed contacts), and runs on +5V, so you can use your servo supply. The best thing, though, is they have 3 versions (2, 4, 8 relays), and even the 8-relay version is only $27. They also sell a nice pre-wired connector that you could use to connect directly to the Medusa DMX, for controlling the relays over a DMX network. Combining these two would get you control of (8) relays, (8) LEDs, and (8) servos over DMX, for under $120.

Here's a closeup of the connection header...


Here's the connections to the Medusa DMX...


And finally, a video, showing it in action...


Here's some links to the relay boards and connectors...
(8) Relay
(4) Relay
(2) Relay

Pre-wired connectors

Note, since this board already includes snubber diodes, there's no need to connect the relay supply to the + terminal on the Medusa DMX switch output terminal block.

- Hook

Great post! Just to clarify, these can be used with any servo controller. You can find them pretty cheap on eBay I've seen 32 channels for like $50. Great way to add pneumatic prop animation into a VSA routine.

Actually, these don't have a microcontroller in them to decode a servo pulse. They require a static logic-level output (not pulsed like a servo requires). Or, they can also accept open collector outputs (ULN2003-style). There are some servo boards out there that can be programmed to have DC outputs, instead of servo pulse outputs), but not all servo boards have this.

The setup shown here has the relays connected to the switch outputs on the Medusa board, not the servo outputs.

- Hook

Ah, my mistake. I just assumed most of the controllers used with VSA had the ability to be configured as a switch. I guess I shouldn't just assume it would work with any controller. Thanks for the info!

This is very useful. I'll have to get one when they reopen on the 10th. I also noticed in one of your pics Hook that you have some kind of connector that makes the connection to the Medusa logic power and DMX terminals. I've thought several times along the lines of, wouldn't it be nice if there was some kind of reducing connector that I could use on those terminals. The holes are so small and the power wires and DMX wires are so big that it's tough to get them in AND once they are in, they seem to come out fairly easily. Can you recommend something that might be insulated and soldered to the power and DMX wires and then has something like a pin that will fit into the Medusa terminals easily?

ChrisIsCreepin,
You may be correct. I see that VSA's got a slot for a few of the servo controllers, for use as relay controllers. I think the Medusa board is still the only one that will control both servos and relays over DMX, though.

buckaneerdude,
This is my unit testing setup, that I'd adapted to show the relay module connections. The quick connection you speak of is made up of a PCB I made in my kitchen, and one of the same connectors I use on the Medusa board. I mounted the connector to the PCB, the power/DMX wires to the PCB, and then screwed-in some short pieces of thin buss wire. Then I screw these into the Medusa board I want to test.

Here's the series of connector I use. It's a 3.5mm spacing part by Phoenix Contact, but Weidmuller and FCI probably have crosses too. However, I haven't been able to find anything with screwdown terminals on both sides, like you'd probably want. The best suggestion I have right now would be to trim some of the conductors from your power/DMX leads before putting them into the terminal block. The board doesn't pull much power, so thinner wires are fine. If they're in there to the proper depth, it's pretty hard to pull them out.

- Hook

[EDIT] - one more option from Phoenix Contact.

Originally Posted by Hooked_on_Scares

ChrisIsCreepin,
You may be correct. I see that VSA's got a slot for a few of the servo controllers, for use as relay controllers. I think the Medusa board is still the only one that will control both servos and relays over DMX, though.

My Board of Chuckee from Skulltronix controls both servos and relays - I used my BoC to control my fog machine as well as my skull servos over DMX, it works quite well. I still would not mind checking out a Medusa board some time in the future, never hurts to have too many control options!

Joe

Joe, which relays are you using with BoC? Do you have a link?

Thanks!
- Hook

Having used both BOC and Medusa I prefer the Medusa. The one thing I like on the BOC over the Medusa is the channel dedicated to the power relay. This can power off the servos for those periods when the prop is idle and save wear and tear on the servos. I don't notice any difference really in the 16bit capability of the BOC over the 8bit for the Medusa and I really don't care much for the BOC configuration program, which by the way, will not work with an Enttec Pro. BOC will work with the Enttec Pro once it has been setup with the config program that requires an Enttec Open.

I currently use RCAT RC100X and RC110 switches - http://www.rcatsystems.com/cube/inde...wCat&Submit=Go. I recent ordered some PicoSwitches - http://www.dimensionengineering.com/picoswitch.htm - which seem to be a little easier to come by and somewhat cheaper. I am also looking at some other multi relay options as well, I will report back on my testing - after Halloween of course!

Joe