Author Topic: Newbie trying to start small - how do I connect LED strip to my Pi?  (Read 1400 times)

Offline Wackychimp

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So I'm trying things out this year as sort of a test & learning experience.  My ultimate goal is to outline the trim/soffit on my house and get a nice color wash.  This year I'm just aiming to do the front porch.  No pixel trees or jumping arches just yet.

I have 3 LED strips from Ray Wu (Everybody loves Raymond) and a shiny new Pi 2 B.  I've heard that the PI itself can drive about 300 pixels - I only need to do 150 this year.  I plan to try to get the Pi up and running over the Thanksgiving holiday but don't know how to connect my strips to the Pi.  I know that they are driven by the GPIO but am not finding anything on which pins get which lines.

On my LED strips I have, a red, white and green (positive, negative and data, I assume). Do I just clip the handy 3 hole plug and wire it into the GPIO?

Here's what I've got:



(EDIT:  Uhm... can new users not post images?  Links: http://imgur.com/wqJQVvb  |  http://imgur.com/Zt7LiMC  )

Thanks for your help!

Offline CaptainMurdoch

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Re: Newbie trying to start small - how do I connect LED strip to my Pi?
« Reply #1 on: November 24, 2015, 04:24:41 PM »
The WS281x output in FPP doesn't work with the Pi v2 B currently.  There is a fork of the library which we are using to drive the direct-attached WS281x pixels on the Pi which is supposed to work on the Pi v2 B, but we have not had a chance yet to integrate and test it, so for now, you need to use either an original B or B+ instead of the v2 B.  The GPIO connections are listed in the Channel Output help page in FPP, so once you have a compatible Pi with FPP installed, go to the channel outputs page and the 'Other' tab.  Hit the 'F1' key or click the 'help' link in the top right below the menu and you should get a popup window with help on the channel outputs.  A connection pinout is listed in there.

The pixel strip should have the + and - connections listed as well as a "DI" on one end and "DO" on the other, the DI is the input data connection.  You need to feed power to the pixel strip separately as indicated in the connection info on the help page.  The ground from the pixel power supply must be connected to the Pi so the Pi and pixels have a common ground reference.
-
Chris

 

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