DiyLightAnimation

Fun => The Porch => Topic started by: mmorlan62 on November 10, 2012, 12:25:20 pm

Title: Hmm. One WS2801 LED setup works but not another
Post by: mmorlan62 on November 10, 2012, 12:25:20 pm

Hi everyone,

This might be too technical a question to post here.  If you know of other blinky light forums I might submit to, let me know.  I've also emailed the writer of the Arduino library I mention below.

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I've successfully used the FastSPI library with my Boarduino to control a WS2801 LED strip of 160 LED's but have major data garbage when using the same Arduino setup to drive some WS2801 pixels modules. 

FastSPI library:
http://code.google.com/p/fastspi/ (http://code.google.com/p/fastspi/)

Here are the products I bought:

LED Strip:
http://www.aliexpress.com/item/5m-DC5V-WS2801IC-256-scale-32pcs-IC-32pcs-5050-SMD-BLACK-PCB-Flexible-Led-Light-Led/613778470.html (http://www.aliexpress.com/item/5m-DC5V-WS2801IC-256-scale-32pcs-IC-32pcs-5050-SMD-BLACK-PCB-Flexible-Led-Light-Led/613778470.html)

LED Modules:
http://www.aliexpress.com/item/WS2801-input-DC12V-3pcs-led-SMD5050-led-modules/610572932.html (http://www.aliexpress.com/item/WS2801-input-DC12V-3pcs-led-SMD5050-led-modules/610572932.html)

The strip works great.  The modules, not so much.  Everything is powered by a PC power supply - 5v for the strip and 12v for the modules.

I've been driving the data lines with the Arduino digital lines just like the strip.  I couldn't find any data on the logic levels so I also tried a resistor divider to drop the data lines to 3.3v.  The  modules act exactly the same.

Here's the LED strip in action (with the count dropped to 20 and a larger delay() on some of the routines):

http://talltalepictures.com/projects/WS2801_LED_strip.MOV (http://talltalepictures.com/projects/WS2801_LED_strip.MOV)

And, here are the modules in action:

http://talltalepictures.com/projects/WS2801_LED_modules.MOV (http://talltalepictures.com/projects/WS2801_LED_modules.MOV)

Does anyone have any ideas why the two systems perform so differently?

Thanks, in advance, for any thoughts you may have to share,

Michael Morlan
512.791.4121

Title: Hmm. One WS2801 LED setup works but not another
Post by: rm357 on November 10, 2012, 05:25:32 pm

Yes, your post is a little technical for our forums. Also we don't really support the 2801 type nodes.

Having said that, there are numerous people here that might PM you directly with more information. We are a friendly bunch and there is a lot of expertise available.

The DIYC forum may be a better place to post for the 2801 nodes, but I.m not sure.

Good luck!