# Has Anybody Made a Custom Light with DMX Interface/Relay Ability?



## delphonic (Sep 20, 2009)

I'm building a lighting system. Most will be off the shelf, but I may build a few custom lights. I'm an electrical engineer (out of practice, but can drudge my way through). My band is currently using a few lights I built with red/blue LEDs and a simple voltage fader. I can mod these to be DMX controllable, but also want to build a few more lights I can control with DMX (I'll be using a computer with a usb/DMX interface).

One idea I have is an array of bright, 1 Watt led's behind the band (you can also find 3-5Watt relatively cheap). Right now I'll probably do all white, but might incorporate some red. I plan to mount 5-10 LEDs on a small pole (7-8ft high or more), with about 4 or 5 poles set up behind the band. The lights are simple to build and won't cost that much.

I'm looking for a more module-based build that I can drop into a project box, wire the connections and go. I'm not interested in lay-out/stuffing boards - I've done that before and it's a pain in the arse.

The main issue I run into is the DMX switching interface. I've found a few boards that will work, but can be expensive. Also, the off-the-shelf dimmers don't really fit my needs because most are 110VAC and don't have a lot of channels/control. I'll want to switch 12-24VDC, so I need something a little more customizable.

I could do 1 channel per pole... but it would be really cool to have each individual light on a channel (think of the crazy flashing you could create with controlling a bunch of hi-power LEDs in a simple array). 

This is the best options I've found so far by Celestial Audio
It's a little more than I wanted to spend @ $260, but it allows up to 48V/4A and 32 channels.

There's also a 4-channel like this one for about $80 bucks.
This is a much more cost-effective route, but limited control.
I'm just curious if anyone has tackled a project like this, or knows of any other options/ideas. With the pre-made boards this would not be difficult. 
If I start this (and I probably will) I'll be sure to post some info/photos/video.. etc.
Thanks guys.


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## mrb (Sep 20, 2009)

unless you have infinite free time and want do make it yourself for the sake of making it yourself then do so, otherwise just buy it off the shelf. Its going to take you quite a bit of time and money to get something working. This isnt something you are going to be able to cobble together for $50 on a one off deal.


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## delphonic (Sep 20, 2009)

mrb said:


> unless you have infinite free time and want do make it yourself for the sake of making it yourself then do so, otherwise just buy it off the shelf. Its going to take you quite a bit of time and money to get something working. This isnt something you are going to be able to cobble together for $50 on a one off deal.


 
I understand your point, and I'm not necessarily looking for a $50 solution. I also want to create something a little different (not that my concept is completely novel). If there's an easy off the shelf solution to produce the same effect I'm open to ideas.

The lights won't take a lot of time and will be inexpensive. I've already made similar lights with no problem at low cost. They just weren't DMX controlled. Building a project box with a few external connectors is also easy. My learning curve isn't steep - only because of my experience.

The 32 channel DMX board I listed in my first post looks very good. Assuming it works as advertised, it's just a matter of throwing it in a box, adding a PSU, wiring the lights to the board, setting the address and go. 

I'm just curious if anyone has done this before and if there's any better options out there for this kind of customization. Other options I've seen are $300-$600 for 1/4 of the channels. I want to stay cost-effective, but I'm willing to pay a few extra dollars to avoid designing and stuffing my own board. I also don't mind a little bit of hassle to allow a little bit of customization in my light show.


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## epimetheus (Sep 20, 2009)

I've actually done what you're talking about with that board from Celestial Audio. I'm an electrical engineer as well. The only reason I would advise going the custom route is if you want some custom physical configuration of the LED's, like building them into a set piece or the like. Chauvet, Elation, Neo-Neon, and numerous others have of the shelf items that work just fine for you're application.

My advice - buy of the shelf and spend extra time/money on a nice controller and programming.


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## delphonic (Sep 20, 2009)

epimetheus said:


> I've actually done what you're talking about with that board from Celestial Audio. I'm an electrical engineer as well. The only reason I would advise going the custom route is if you want some custom physical configuration of the LED's, like building them into a set piece or the like. Chauvet, Elation, Neo-Neon, and numerous others have of the shelf items that work just fine for you're application.
> 
> My advice - buy of the shelf and spend extra time/money on a nice controller and programming.


 
How was your experience with that board? Any issues?

I don't see a cost-effective solution for creating what I'm looking for with off the shelf lights: An array of 30 bright "pin spots" I can "strobe", all controlled individually. In addition, the lights I'm thinking of building will be light and quick/easy to setup.


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## derekleffew (Sep 21, 2009)

delphonic said:


> ...I could do 1 channel per pole... but it would be really cool to have each individual light on a channel (think of the crazy flashing you could create with controlling a bunch of hi-power LEDs in a simple array)....



So you're looking to build something like http://www.controlbooth.com/forums/lighting/15259-interesting-fixture-chromlech-jarag.html, but with LEDs as the source instead of PAR20/30 lamps? Sounds like an interesting project, but I agree with the above. Building the fixture(s) is not as difficult as programming it. Unless the console/media server includes pixel mapping, programming can be a nightmare.


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## dramatech (Sep 21, 2009)

Northlight DMX systems has a variety of circuit boards that control LEDs, solid state relays, hobby servos, regular relays, and motors. The boards are moderately priced and very personal service. The website has a crazy address that I don't know how to link to this post, but you can find it on a google search, and it is in several posts on Control Booth. I believe it can be found under some DIY posts. [Edit: see DIY DMX: Demux, Protocol Converters, etc.] It is located in Tempe, AZ.


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## epimetheus (Sep 21, 2009)

delphonic said:


> How was your experience with that board? Any issues?
> 
> I don't see a cost-effective solution for creating what I'm looking for with off the shelf lights: An array of 30 bright "pin spots" I can "strobe", all controlled individually. In addition, the lights I'm thinking of building will be light and quick/easy to setup.



I have had zero issues with the Celestial board. In my opinion it is a great little niche product. It would be my first choice to do what you want. Products from Northlight and Blue Point Engineering are also viable alternatives.

BTW, the version shown on the website is out of date. There is a version 2 that has improved specs all the way around. Something like 8A per channel and 60A total. Plus the board will run off the LED supply voltage, no second source required, and it has connecters for DMX in and thru. I'll try to remember to post some pictures of my test rig tonight.


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## delphonic (Sep 21, 2009)

Derekleffew - that light you linked is interesting, but not what I'm looking for. I admittingly don't have a lot of experience with DMX consoles & programming. I'll be using software, and I'm assuming if I know the board specs I should be able to tell it what to do fairly easily with the software (maybe a naive assumption, but electrically it makes sense to me). I don't think I need to get as drastic as pixel mapping unless I want to get ridiculous with the number of lights.

Dramtech - actually one of the links in my first post was to the 4-channel version of the Northlight DMX board. More cost effective, but less channels.

Epimetheus - thanks for the info, I'll definitely check out Rev 2. Right now that's the best option I've seen so far. Have you used this board with high-power LEDs that require constant current drivers (I know the purpose of this board is for those applications)? That is one area I need to read up. I'm assuming hooking a driver up between my source and switches should be sufficient (if driver is big enough). Though, I have some high-quality PSUs that are meant to supply constant current regardless of load... so wondering if I even need the drivers if I set up my current limiting correctly... but again I haven't dealt with those too much... so I'm sure there's a "duh" factor I'm missing.

Thanks!


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## epimetheus (Sep 21, 2009)

The Celestial board is just DMX controlled PWM. It does not provide current regulation. My test rig using that board has LED strips that are self-contained and designed for a 12V source. I think it's probably best if you use LED's that either don't require a driver, or have the driver built in. You also might have issues with LED modules that require lower voltages, such as 3.3V. Since the board electronics get their power from the LED supply, the LED supply has to be at least 5V, maybe 12V, I'm not sure.


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## delphonic (Sep 21, 2009)

Yes, I figured the celestial board didn't provide current regulation. The problem with LEDs with built-in drivers is that they're not as cost-effective. Using a seperated driver that can supple a cluster of LEDs is cheaper. And, I haven't seen LED's yet that are high-output and don't require a driver (maybe I need to explore my LED options a little more). The problem with strips is that I can't control the lights individually.

I can power the board from the PSU directly, and put the driver between the PSU and LED 'common'. Unless there's something with driver setup I'm not aware of, I don't see why this wouldn't work. I don't plan on using low voltage, but I'm sure I have a few regulators laying around I can throw in there if need-be.

Thanks again for the input. I emailed celestial about the rev. 2 board.


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## delphonic (Sep 21, 2009)

epimetheus said:


> The Celestial board is just DMX controlled PWM. It does not provide current regulation.


 
Your comment just sank it... I might need to look to see how the board pulls power vs. how it runs the LED source & PWM. I don't know if using PWM will affect the operation of the LEDS, though the purpose of the board is for this type of LED (from what I can tell).


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## epimetheus (Sep 21, 2009)

delphonic said:


> Your comment just sank it... I might need to look to see how the board pulls power vs. how it runs the LED source & PWM. I don't know if using PWM will affect the operation of the LEDS, though the purpose of the board is for this type of LED (from what I can tell).



Do you have a particular LED in mind? I might be of more help if I can see a cut sheet.


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## delphonic (Sep 21, 2009)

I don't have a particular LED in mind just yet, but something like this is along the line of what I was considering (though you can find cheaper LED/Drivers than Luxeon).

One of the major drawbacks to the high-power LEDs is that drivers can still be relatively expensive. I also just realize another "duh" factor... If I want the ability to control every single light individually, I'd have to run then in parrallel with respect to my driver. This would probably require a whole array of drivers to supply enough current. Even if I did 350mA LED's this would require a current source of 3x350mA => ~11A, when most drivers are <1A. Having the type of control I was hoping for starts to become costly when you factor this into the equation. Having 1 or 2 channels per light is starting to become more & more appealing.

Of course I could avoid this complication if I can find a LEDs that don't required a driver. I was thinking the higher power are automatically brighter, but if there's a good alternative I'm interested. I basically just want something that's going to create a fairly bright flash. I also planned to use a collimator of some kind. 

Yeah, Yeah... I know, I know... this stuff is always so much easier in concept, in my head... I'm sure "told you so" will apply eventually.... but I'm still a stubborn bastard and will probably try anyway.


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## epimetheus (Sep 21, 2009)

I don't think you need a driver as long as you use PWM for dimming. An alternative to PWM dimming is varying the current, which would require a driver. For example, say the LED you want to use is rated at 350mA @ 3.3V nominal. Put a 25ohm resistor in series to make a 12V LED module. If you PWM this module, the module always sees 350mA, constant current. The duty cycle just gives the impression of dimming, without a driver. You could also use a couple of LED's in series instead of the resistor.

My point is I don't think you need the driver.

On a side note, all this talk is inspiring me. I'm thinking a piece of 2" square aluminum tube would make a good mounting medium as well as serve double duty as the heatsink for 1W/3W/5W LED's.


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## epimetheus (Sep 21, 2009)

This is the test rig I built for playing with custom LED's and DMX control. It's wired up as 9 RGB cells.


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## delphonic (Sep 21, 2009)

epimetheus said:


> On a side note, all this talk is inspiring me. I'm thinking a piece of 2" square aluminum tube would make a good mounting medium as well as serve double duty as the heatsink for 1W/3W/5W LED's.


 
Ha ha, that is exactly what I was thinking - especially once I saw the heatsink requirements for the hi-power LEDs. Originally I was thinking a piece of PVC pipe would work well, but definitely leaning towards aluminum now. I was also thinking 2 pieces of shallow U-brackets, one with a slightly larger diamater than the other, would allow you to interlock the two sides together and throw a few screws in the side to keep them together. This would make wiring & servicing easier. []

I'm not sure I understand how PWM can get around the high-power LED drivers. Jesse from Celestial got back to me (there are new Rev 2 boards at the same price). He also pointed out that the LED drivers will deliver continuous current regardless of voltage load, and the high-power LEDs can vary over time (and I think temp). If you set up the system with only limiting resistors, it might not accomodate for voltage shifts if your supply is only keeping voltage contstant (and pulling whatever current you regulate).

****! That's a nice setup! You're killing me! What effect are you planning to acheive? What power are those LEDs?

Another note, Jesse also mentioned a site with some really cheap LED drivers (actually, the whole site looks like it's full of cheap chinese crap, but it's so cheap I don't know if I'll be able to help but buy some things to play around with!) Here's a cheap driver from there. $2.39 per channel ain't bad. I suspect that many of the problems people are seeing are from in-proper heatsinking... well... and they're probably low quality. There's also several others on there that are a little more hefty and you could probably get more life with a smaller duty cycle. Something similar to these lights could look really cool... they've got a few options on there (and really cheap hi-power LEDs (including RGBs). It's a gamble with quality but some of it is inexpensive enough that it'd be worth playing around with. 

However, those drivers would not allow for dimming... and I'm sure dimming drivers would be expensive. This might bring me back to a small cluster of lower power LEDs where a limiting resistor will definitely work, and will be dimmable. 

Does anyone know how much brighter superflux LEDs (really) are compared to a normal package?

Thanks for the input!


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## epimetheus (Sep 21, 2009)

Not really trying to achieve any effect inparticular, just trying to play around with RGB control. We're fixing to get quite a few LED fixtures at my church and I wanted to play with color effects and the like. I guess my thinking as far as not needing the driver is that with the current limiting resistor in place, you'll never over power the LED's. They're always seeing less than maximum current. I would account for any possible drift by oversizing the resistor and running the LED slightly below its rating. I haven't had any problems with this method, though I also haven't tested longevity either.


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## epimetheus (Sep 21, 2009)

LZ1-10CW05 LedEngin LEDs - High Power

Something like this is what I'm thinking...


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