DMX LED RGB Decoders

[sundown]

I am relatively new to this so please forgive me if there are some basic questions here. I have used a few different software packages controlling upto 30-40 LED Panals before and have a basic understanding of DMX but thats about it.

 

 

I wish to power multiple lines of RGB LEDs without having any control boards next to the lights. So a string of say 8 RGB LEDs in a row spaced about a foot apart. Then I want to use DMX to control these with DMX software/desk.

 

As far as I understand it at the moment I will need a DMX decoder at the end of each string and then to run the individual wires down the line to the LEDs.

 

I have found a chinese model - http://www.ltech.cn/english/product/DMX-512-Decoder.html - would this be a bad way idea to go with, or there other more suitable products?

 

Is this the right way to go about the project or is there are simpler/cheaper way to go with it, because this method seems to be getting rather pricey. I will not need a massive amount of LEDs at each of the 8 points so is there potentially a cheaper or DIY decoder I could make.

 

I would appreciate any help. Thanks

[andrewg112]

It might help a little more if you could tell us what lighting product your using?

 

Andy,

[paulears]

I think he means strings of LEDs, as in individual components, rather than proper fixtures - hence the 'led strings'. I was a bit confused too.

[Smiffy]

This one may be, if ever there was one, a post whereby the term 'Get a Professional In' has never been more appropriate.

 

It might cost a few quid, but sounds to me like it might in the long run save you time, and the replacement of numerous LED 'Strings'

 

Just a thought

 

Smiffy

[musht]

Think its more budget end than asking Glasson for a quote, have a look at

 

http://response-box.com/rgb/

 

Which is now kind of jumping DMX to Artnet

[sundown]

Apologies for the wording of the last message. Reading over it it is not very clear.

 

Again I am pretty much a beginner but I am spending a lot of time readin up on this so hopefully I will start to understand it all pretty quickly. Again I would be greatfull for any advise and sorry if I am making obvious mistakes/asking stupid questions

 

 

 

Heres where Im at:

 

 

DMX software Package

 

-->

 

DMX Interface

 

--->

 

Control Board (with Power supply)

 

Looking maybe buying one of these: http://www.celestialaudio.com/ca_dmx_48/index.html

 

Does that look right for the task? Cheap/Expensive?

 

-->

 

RGB LED Clusters

 

with 48 outputs on the control board and 3 channels needed to go to the red, green and blue of each the 8 lights in the chain. I can do 2 chains of 8 per control board.

 

Each light I was looking to maybe create out of 2 pieces of stripboard back to back with LEDs stuck directly on surrounded by a plastic ball of some sort. Is this a good way to go about making the light?

 

I was going to calculate the amount of LEDs and resistors on this: http://led.linear1.org/led.wiz

 

 

 

 

What Im currently trying to figure out:

 

Whats the deal with different color LEDs, the manufactor website suggests that:

 

Green are much strong than blue, even more so than Red.

 

Green LEDs w/ 30-40 degree spread - max 16000 lumins

Blue LEDs w/ 30-40 degree spread - max 4180 lumis

Red LEDs w/ 30-40 degree spread - max 2000 lumins

 

Does this mean I need a larger amount of Red than Green?

 

 

My LED light I have currently suggests otherwise with almost twice as many Greens as Reds.

http://www.americandj.eu/default/led-punch-pro.html

 

 

If you read this, thanks for you time.

[musht]

>>Looking maybe buying one of these: http://www.celestialaudio.com/ca_dmx_48/index.html

 

>>Does that look right for the task? Cheap/Expensive?

 

Good product, not expensive for what it does, the outputs are current sinks , no resistor needed.

 

>>Each light I was looking to maybe create out of 2 pieces of stripboard back to back with LEDs stuck directly on surrounded by a plastic ball of some sort. Is this a good way to go about making the light?

 

Depends how it needs to look really, watch about keeping the cable captive.

 

>>Whats the deal with different color LEDs

 

Lumens are adjusted to eye sensitivity, eye most sensitive to green around 555nm, drops off either side, green measures highest for lumens per watt, red can look very dim further past 630nm you go, below its looking orange.

 

Buy 4 legged common Anode RGB LEDs from a decent supplier and they`ll be matched OK.

 

Keeping it simpler in real terms, look through response bo RGB lights links, much simpler to wire , each LED has a serial decoder on the LED and only requires 3 wires power, data and ground daisy chained to all LEDs, DMX to serial converter/PSU handles the DMX to LED bit.

[timsabre]

>>Whats the deal with different color LEDs

 

Lumens are adjusted to eye sensitivity, eye most sensitive to green around 555nm, drops off either side, green measures highest for lumens per watt, red can look very dim further past 630nm you go, below its looking orange.

 

Buy 4 legged common Anode RGB LEDs from a decent supplier and they`ll be matched OK.

 

If you do use RGB LEDs (i.e. the R,G,B all in the same lamp) you will not get anywhere near those lumen figures you gave.

 

If you use individual RGB LEDs, the light output varies widely between different LED manufacturers - this is probably why your ADJ light has more greens. You have to balance it for the particular type of LED you use.

 

Are you planning on having more than one of each colour LED in your "clusters"? If so how are you planning to connect them - the Celestial Audio board only goes up to 15V which will only allow 3 LEDs on each circuit.

[smalljoshua]

Couldn't you just use an out of the box solution?

 

Such as these.

 

http://response-box.com/rgb/2010-node-store/

 

Josh

[musht]

If you do use RGB LEDs (i.e. the R,G,B all in the same lamp) you will not get anywhere near those lumen figures you gave.

 

Weeell, in leaded LEDs nowadays, everythings going SMD ceramic subtstrate allows a bit more oomph, SMD RGB on carrier card one way to go.

 

Something wrong with those lumen figures

 

>>Green LEDs w/ 30-40 degree spread - max 16000 lumins

 

16000 Lumens , that would be some LED, super efficient would be 100l/W....

 

Guess its actually candela which is directional, narrower beam higher candela figure.

[sundown]

Thanks so much. This is exactly the advice I needed.

 

Yes your right they are candela figures not lumens.

 

Reason for not buying them in clusters is because Im making 512 of them so the unit price really counts.

 

 

 

 

Am thinking of buying some of these:

 

http://www.hebeiltd.com.cn/led.strip/STR3.pdf

 

Cheap simple 3 LED strips. I know this supplier is pretty cheap (from what I have seen) so is it likely that one of Each R,G,B will combine to give an equal output for color mixing?

 

 

 

"Are you planning on having more than one of each colour LED in your "clusters"? If so how are you planning to connect them - the Celestial Audio board only goes up to 15V which will only allow 3 LEDs on each circuit."

 

Will the board work with the above strip?

 

On the site it says the board is 20mA but can be raised to as high as 80mA. The unit is rated at 40mA which is potentially ok? (sorry if my knowledge of electronics is not correct here, I will be reading up on it as we go)

 

Would it be possible to wire 2 of them in parallel off a single channel and for it to work with the 80mA board?

 

 

 

 

The LEDs are going to be contained inside little plastic balls (just larger than the lights themselves), so the look of them is not important, but will there be a heat issue?

 

 

"watch about keeping the cable captive."

 

Didnt really understand this. Was going to connect everything via basic ribbon cable, but havent looked to far into this yet. Is that wise?

 

 

Again thanks for the help.

[timsabre]

"Are you planning on having more than one of each colour LED in your "clusters"? If so how are you planning to connect them - the Celestial Audio board only goes up to 15V which will only allow 3 LEDs on each circuit."

 

Will the board work with the above strip?

 

On the site it says the board is 20mA but can be raised to as high as 80mA. The unit is rated at 40mA which is potentially ok? (sorry if my knowledge of electronics is not correct here, I will be reading up on it as we go)

 

Would it be possible to wire 2 of them in parallel off a single channel and for it to work with the 80mA board?

 

If wiring the LED's in parallel, you need to have a resistor in series with each LED. The LEDs often have different forward voltages, if you just connect them directly in parallel you find that one LED takes all the current and the other gets hardly any.

 

It's better and more power-efficient to wire the LEDs in series, but each LED (green or blue) needs about 4V to work, so on a 15V supply you can only get 3. This means you get 3 leds for your 20mA - if you've got a lot of LEDs it makes a big difference in the power supply you need.