RGB led for live concert

Hi all, i made an 8 shiftbrite RGB led chain drived by an arduino, controlled via USB by a labview sw running on PC

The system driver (PC sw + arduino sw) is able to drive 120 shiftbrite at 25 fps, using a 56700bps serial connection and more (potentially double) using a 115.2kbps (right now at that speed i have some problem of data corruption)

On PC run a "effect panel" written also in LabVIEW able to generate pattern, color, fading and so on and pass to driver for display on LED.

Th video show what a single "effect panel" can do, the effect was controlled "live" by me during the song.


Did you think of DMX control for your light?

Hi, yes could be an option, but i would like to avoid to made a "static" system able only to receive command via DMX on which pattern show because this at the end result in a finite number of effect with few parameter controllable vi DMX. I thinsk that this is the main lack of DMX, but i'm not an expert, i instead would like to develope a new way to controll the light tah give the max flessibility to the light designer\performer i'm developing a sw on pc to doing this the limit right now is that i can control one parameter at time... one mouse pointer= one parameter i would like to develope a console, also using arduino and some slider knob and button, to interact with the pc control sw.


Looks great! Felt like a real concert!

Maybe you could figure out a multi-touch application to turn virtual knobs and sliders on the PC!


yes the multi touch options is fascinating us, something like this http://www.jazzmutant.com/lemur_overview.php ok but the next stes will be build a real phisical console whit old style rela plastic sliders, buttons, and knobs ::)

I would stick with DMX if I were you. I've built a system using an Arduino, two TLC5940 LED driver chips, and 10 Piranha RGB LEDs. They use DMX and I am using MagicQ lighting software on my PC to control them. The software allows me to have complete control over the color of each LED so that if I had enough of them, I could build a low-resolution LED video screen. The software allows me to create a grid of 'pixels' and to have scrolling text or moving images as well as color effects. It is well worth a look.

Hi thanks for teh tip, i'll give a look to MagicQ sw. For sure DMX support open my systems to a lot of hardware\software present right now on the marketplace but what i want to achive is create a custom software because this for sure can give me more and more flexibility respect a general software. You speak about a low res led video screen, this is very intresting fo me, do you have just build screen or you have only 10 led right now? I figure out a lot of problem in data transmission speed and distance when i was facing out to make a screen, adnd this problem are still around, so if have any tips also oh this ... Consider that my final project coulfd be use 2000 Rgb led composing a wall on 2x12 meters

I don't think that custom software would necessarily give you more control. Have a look at the MagicQ software. I think you will be surprised at just how powerful it is.

I only have 10 rgb leds at the moment. Work gets in the way of me playing! If I were to make a low-res video screen, it would be very low-res. Each led 'pixel' would need 3 dmx channels so one 512 channel dmx universe would only give me 170 pixels. For your application, you'd need 12 universes! MagicQ can handle this many universes, but you'd need some expensive Artnet to DMX interfaces.

The data rate shouldn't be a problem though. For a full 512 channel dmx datastream, you'd get at most 44 updates per second. Having more than one universe won't be a problem as they get sent in parallel.

That looks awsome :o! I saw macegr's knight rider's effect the other day, :o. I wish I could make something like that but I can't afford all the shiftbrite LEDs. I'm thinking of maybe 24 LEDs. Are there any shift-register-based single color lights? I just need to show different intensity of light but not really different colors. I hope if someone makes those I can afford some. Thanks.

lidur thanks!
yes the TLC5940 16-channel PWM chip can fit your need also exist a lib for arduino here http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1218174457
The chip support 16 PWM ch whit a resolution of 4096 each daisy chain is also possible so you can obtain more than 16 ch… the chip can be used also to contrlon RGB led using 3 ch for each

The TLC5947 is even better, it's like a ShiftBrite with 24 channels instead of 3, or a 24-channel TLC5940 except with an internal PWM oscillator and automatic cycle restart, removing the biggest problem with the TLC5940.

The only downside is that it only comes on QFN and HTSSOP, but I am making some breakout boards for it.

yes, you are right that chip seems to be very simple to interface, maybe the serial protocol is similar to the A6281 one, and simpler respect the TLC5940 that don't have the integrated PWM. I just ordered 5 samples in HTSSOP package simpler to manage than QFN...

Thanks guys. I'll look into these chips you suggested. Does that mean I can use regular LEDs and regulate their intensities with PWM output from these chips?

Yes you can, each output support 30mA current this is enought for regular led that are typical rated for 20mA.

PS searching in my desk i discover that i already 10 TLC5947 that i completelly forgot when stared to work whit SB... i have to prepare my breakout board now 8-)

Yep…the TLC5947 is relatively new and no one knows about it. I have a breakout board that is actually the same idea as the ShiftBrite, except with 8 RGB surface mount LEDs in 0.5" spacing. Additionally, I have a breakout board with headers that allow controlling either 24 individual LEDs or 8 RGB LEDs on mini PCBs with cables. It is still much more wire length required than a ShiftBrite chain since it’s a star topology instead of daisy chained LEDs, but it will allow more flexible installations. If you wanted 96 LEDs randomly scattered across an area with 2 to 3 feet between them, the ShiftBrite idea would fail but the TLC5947 solution would be perfect.

garrett you can read my mind? :) i have the same idea about the stick board with littel pixel pitch and also about the star topology. The SB are a good product but any application is different and may be i'm conviced that we can address each solution for 2 great macro area of application

A6281 for driving mid-high power led for accent light\architectural ecc TLC5947 for driving a lot of little LED also for build low-mid resolution led wall.

have you already a piece of code that drive the TLC5947?

Nope I'm using the QFN package and therefore still waiting for my prototype boards to arrive. :(

But it will be very very similar to ShiftBrite code.

we build the second prototype, find a short video here http://www.agilesystems.it/?p=56.
Next step should be ade the final project, a 8x2 meters led wall, if customers like the concept.

I am new to surface mount...is there any way to prototype these TLC5947 chips without designing and ordering a breakout board?

yes there is, a friend of mine wire up 2 of these… we spent 5 hours to do… :-?
if you accept a suggestion, buy a breakout board.