[AndyJones]

Hey guys-
I have a project coming up where I need a heck of a lot of Leds cells. Each cell only needs to consist of a 4x leds rgba. But each led needs to be individually controllable- and I need a heck of a lot of them. (well over 1000 cells)

The desirable way would be to be able to send a 5 core cable to each cell (rgba -ve) and then have a board with a single DMX input that can then deal with the control of all of the led's.(all 128 per universe, buffered at 32 each line I guess?)

Is this possible- I'm kind of interested in making my own solution if it's possible...

[dbuckley]

In my opinion you are using a sledgehammer to crack a nut.

Individual control of lots of LEDs is possible, from DMX, but not directly; the "normal" approach is to use LED controller chips that have a shift register and all the drive smarts (in some cases including PWM dimming) on the chip. If you didn't want to do this exactly (perhaps because you don't like the dimmer curve) then you could replicate the technology with PIC chips or something similar.

Google for ws2801 led for a decent drive chip. Switch to images to see many examples of it in operation. Search aliexpress for ws2801 to see what is commercially available.

Keep us posted!

[ImagineerTom]

http://response-box.com/rgb/ - ready made, fully tested, modular LED pixel type system that you should be able to do the job. If he hasn't got an off-the-shelf product that works he'll probably be able to tell you who has

[jono9691]

I'd shoot Chroma-Q's technical dept. and email or call with some specifics, I'm sure you know about
their rgb color web. If anyone can point you in the right direction if not help assist you in building this, they should
be able too.

[musht]

Various chips like the 2801 and 2803 et al are the way ahead, DMX runs out of channels fast and differential connection unnecessary hassle on short connections.

bit more ready built:

http://www.glassonelectronics.co.uk/

http://www.components-company.com

[Nicktaylor]

jono9691, on 29 February 2012 - 10:12 PM, said:

I'd shoot Chroma-Q's technical dept. and email or call with some specifics, I'm sure you know about
their rgb color web. If anyone can point you in the right direction if not help assist you in building this, they should
be able too.

If in the UK contact AC Entertainment as I believe they are the UK distributer for Chroma Q

I must say their LED stuff sprang to mind reading the first post, not that I have ever had the budget to use such things!

[slipstream]

would depend what you are actually doing but the low res led curtains can manage images -
and if your looking at specific pixel illumination you could probably drive them as frames

This post has been edited by slipstream: 01 March 2012 - 07:33 PM

[AndyJones]

Hello Everyone,

Thanks to those who have taken the time to reply! I typed my post in the pub on an iPhone. As this is the first time I've got back to my laptop- I thought I would update you with a bit more information...

Basically the cells need to be able to float as they will be on a lake, with about 1m to 2m between cells. So I guess I need a controller of some kind and then 10 strings or so of LED's coming off of that. My current thought is to see if I can adjust the http://response-box.com/rgb/ to meet my needs. I would really love to build the whole thing from scratch using Davids ws2801 chips- but I'm not sure if I have the knowledge- which is a shame!

Thanks guys!

[dbuckley]

Howzabout these?

[dosxuk]

Have a look at Artistic Licence who have a wealth of LED stuff and who made the Colour Web stuff for Chroma Q. The updated version of the colour web components is IP67 rated so may be suitable.

[jono9691]

The man hours alone would be massive to build a project this size from scratch. Sounds like fun

[mala]

If you are still interested in a making your own solution, These small DMX RGB drivers may be of interest to you.



I purchased a load for a project and now have about 50 with 2.54mm pitch vertical header pins fitted that I no longer need (was actually about to put these and some other bits on ebay, when I saw this post)

the pcb is 25*25*7mm and each channel can drive 3W at 12V ,voltage input can be between 5-24V.
The best thing about these as far as I'm concerned is that they are auto addressing and you only need 1 wire going from the TX of one board to the RX of the next to daisychain data.
The onboard MCU is a STC11 F02E which can be flashed in place on the board..so you can for example "burn" a permanent address to it if needed.
I have 52 built into a rig which is controlled by a pharos LPC2 with no refresh problems.

They are only RGB and I saw you mentioned RGBA in your original post....so maybe not exactly what you are looking for, plus of course you are going to have to come up with a waterproof enclosure.
The reason I went for these over the WS2801 etc, was that they were easily usable to drive higher output LEDs ,I've been using them with 3 x 1.5W white LEDs or 1 x 2.5W RGB LEDs.

Drop me a PM if you think they may be of use, I'd be happy to supply a couple for you to test.
Cheers,
Merry

[vincent81]

You can buy WS2801 LED pixels and the 5v power supply for much cheaper directly from China.