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The Digispark => Digispark (Original) Support => Topic started by: harrygb on August 30, 2015, 08:23:08 am

Title: Which LED strip to use?
Post by: harrygb on August 30, 2015, 08:23:08 am

Hello all,

I am looking to produce an LED display much like the below which will be made up of approx 50m of strip:

https://www.youtube.com/watch?v=XKKr1ncRgNg

At this time i am trying to select the correct controller and LED strip.  Ideally the strip needs to contain close to 35/40 pixels per meter and have a high resolution of colour change and accuracy, via the controller.

I see many articles that talk about LPD8806 v WS2801, but generally does any one have any better ideas or should one use the strips i have mentioned?  If so which one?  Secondly which controller will allow for standalone use to allow for program change etc?

Thanks,

Harry

Title: Re: Which LED strip to use?
Post by: exeng on August 30, 2015, 08:49:29 am

You may want to check this out... http://rgb-123.com/
I don't believe Ryan carries the type of LED strip you are looking for but does manufacture and sell controllers and power distribution equipment for large LED displays as well as LED matrixes and small strips.  Ryan is well versed in LED display technology and should be able to point you in the right direction and perhaps provide some of the equipment you are going to need.

I'm not affiliated with RGB-123. I discovered them through Kickstarter and have used some of their small LED matrixes and LED strips. 

Title: Re: Which LED strip to use?
Post by: dougal on August 31, 2015, 06:47:46 am

WS2812 based strips are the most common, and are widely supported. On the plus side, you only need one data line to control a strip. On the down side, they use a timing-sensitive protocol which generally means that your controller spends a lot of CPU time managing that communication. Generally speaking, it's not a problem, but that might depend on your particular application.

You might want to try APA102 strips: https://cpldcpu.wordpress.com/2014/08/27/apa102/

Adafruit calls these "DotStar", and you can, of course, find decent prices on sites like eBay or AliExpress. They apparently have better color overall color resolution and faster PWM than WS2812 modules, but cost a little bit more. These use separate clock and data lines, so your controller can drive them as fast as possible, without worrying about sensitive timing issues.

LPD8806 strips are also pretty popular, might be slightly less expensive, and have good library support since they've been around for a long time. They also use separate clock and data.

For controllers, you might look at the FadeCandy board, or maybe the Octo WS2811 and Teensy 3.1.

Title: Re: Which LED strip to use?
Post by: harrygb on August 31, 2015, 02:03:04 pm

Hi Guys,

Many thanks for your reply.  Can you kindly explain the difference between the APA102 (A1) and the APA102C (A2)?  I have been told that APA offers the best resolution and colour control.  But not sure how that can be given the IC on the WS2801, but what do you think?  Does the IC make the strip perform better? (see attached)

What do you think about the T-8000A controller for use with any of the above?

Harry

Title: Re: Which LED strip to use?
Post by: exeng on September 01, 2015, 08:43:49 am

From what I've read (not experience) one has better heat conduction.
https://cpldcpu.wordpress.com/2014/08/27/apa102/