Design Con 2015
Breaking News
Comments
Newest First | Oldest First | Threaded View
Page 1 / 2   >   >>
Max The Magnificent
User Rank
Blogger
Re: Keep testing your NeoPixel ring, use the next pixel
Max The Magnificent   1/8/2014 9:50:24 AM
NO RATINGS
@n7ray: I'll second that.  Have fixed two rings that I thought were toast by replacing the first LED in each.

Cool Beans -- I will have a bash at swapping my first pixel out -- also I'm going to take much better anti-static protection when handling the little scamps from here-on-in. 

 

n7ray
User Rank
Rookie
Re: Keep testing your NeoPixel ring, use the next pixel
n7ray   1/7/2014 8:49:18 PM
NO RATINGS
I'll second that.  Have fixed two rings that I thought were toast by replacing the first LED in each.  

BTW: If you want an easy way to drive hundreds of them, check out this project:

 

(The PSOC 4 boards are only $25)

http://www.element14.com/community/message/89756/l/psoc-4-pioneer-kit-community-project100-psoc-4-times-square-led-billboard#89756

Max The Magnificent
User Rank
Blogger
Re: Keep testing your NeoPixel ring, use the next pixel
Max The Magnificent   1/6/2014 12:15:54 PM
NO RATINGS
@sdtrent: You should not trash your NeoPixel ring just yet. Try powering the ring and sending your data into the data-in line on the second pixel, or third, etc. There is a chance that the first pixel is damaged and not flowing the signal data to the next pixel in the chain.

That's actually a really good idea -- and, in fact, if that works, then it probably wouldn't be too difficult to simply replace the first pixel... thanks for the suggestion.

sdtrent
User Rank
Rookie
Keep testing your NeoPixel ring, use the next pixel
sdtrent   1/3/2014 6:12:11 PM
NO RATINGS

You should not trash your NeoPixel ring just yet. Try powering the ring and sending your data into the data-in line on the second pixel, or third, etc. There is a chance that the first pixel is damaged and not flowing the signal data to the next pixel in the chain. Other than overvoltage, I would be surprised if you managed to kill all of the pixels.

Also, part of the perceived update speed is that the pixel LED data is updated for the desired pixels before SHOW is used to update the output currents of the whole strip at one time. This allows a flicker free update because you are not seeing the changes in each pixel each time the individual pixel's data is updated.

Shane

George Hahn
User Rank
Rookie
Re: Addressing
George Hahn   1/3/2014 4:17:18 PM
NO RATINGS
@Marty MacGyver

You can control them with a BeagleBone Black though. Look into the pair of programmable realtime units on the SoC.

Max The Magnificent
User Rank
Blogger
Re: Addressing
Max The Magnificent   1/3/2014 1:15:46 PM
NO RATINGS
@Marty: I've pondered putting a small FPGA board between an Arduino (or RPi, or something else) and using it as a high-speed dedicated controller for my WS2812-based ring, matrix and strip.

Thanks for the great information -- very interesting -- and if you do use an FPGA to do this, I woudl LOVE for you to write the project up and to post it for others to peruse and ponder here on EE Times.

Marty MacGyver
User Rank
Rookie
Re: Addressing
Marty MacGyver   1/3/2014 1:12:22 PM
NO RATINGS
I was messing around with these LEDs long before they were called "NeoPixels". First, the LED units are the WS2812 (or WS2812b, which is better suited to the higher current paths large strips and arrays demand). That unit consists of a 5050 SMT RGB LED combined with a WS2811 controller.

The WS2811 protocol is detailed in the datasheets as well as numerous sites (I found http://hackaday.com/2012/12/07/driving-a-ws2811-rgb-led-pixel/ to be helpful when I was getting started with it). Conceptually, it works like this: at any point after a 50 us quiet period (data line held low) a given led is ready for input. The first WS2811 in the chain reads 24 bits (8 bits each for red, green, and blue), and after that it just forwards the rest of the bits downstream. The next WS2811 does the same, and so forth, until you stop sending data (obviously extra data beyond the last LED goes nowhere).

You can search for the WS2811 datasheet and see the exact timings involved (there's both a low and a high speed mode).

Keep in mind that the AVR at 16 MHz doesn't allow a lot of overhead for data processing. I managed at one point to marry the strip with a controller... but there wasn't a lot of room to do anything else:

http://www.falatic.com/index.php/72/github-long-time-user-first-time-contributor

I've pondered putting a small FPGA board between an Arduino (or RPi, or something else) and using it as a high-speed dedicated controller for my WS2812-based ring, matrix and strip.

PS: it's virtually impossible to directly control these with a Raspberry Pi... which is another reason I'm considering the FPGA idea as I revisit these projects.

 

Max The Magnificent
User Rank
Blogger
Re: Coax connector
Max The Magnificent   1/3/2014 11:20:31 AM
NO RATINGS
@bobdvb: Those coax power connectors are quite readily available...

I agree -- the thing was that I'd never looked for one before, so when I realized I could do with one and there was one on the Adafruit site I thought "Wow -- that's a good idea!"

bobdvb
User Rank
Manager
Duane Benson
User Rank
Blogger
Re: Product placement?
Duane Benson   1/2/2014 7:06:03 PM
NO RATINGS
Adafruit sells products of their own design and products of someone else's design. What I really like about them is the amount of value that add to whatever it is they're selling. The libraries and tutorials they provide are pretty incredible in terms of quality and breadth. They also give a lot of support to what used to be a re-emerging hobby community, but is now also a re-emerging small start-up business community.

Page 1 / 2   >   >>


Top Comments of the Week
Flash Poll
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Carlos Bueno

Adventures in Userland
Carlos Bueno
Post a comment
Editor’s Note: Excerpted from Lauren Ipsum: A story about computer science and other improbable things, author Carlos Bueno introduces us to Lauren and her adventures in ...

Max Maxfield

Tired Old iPad 2 vs. Shiny New iPad Air 2
Max Maxfield
8 comments
I remember when the first iPad came out deep in the mists of time we used to call 2010. Actually, that's only four years ago, but it seems like a lifetime away -- I mean; can you remember ...

Martin Rowe

Make This Engineering Museum a Reality
Martin Rowe
Post a comment
Vincent Valentine is a man on a mission. He wants to make the first house to ever have a telephone into a telephone museum. Without help, it may not happen.

Rich Quinnell

Making the Grade in Industrial Design
Rich Quinnell
16 comments
As every developer knows, there are the paper specifications for a product design, and then there are the real requirements. The paper specs are dry, bland, and rigidly numeric, making ...

Special Video Section
The LT8640 is a 42V, 5A synchronous step-down regulator ...
The LTC2000 high-speed DAC has low noise and excellent ...
How do you protect the load and ensure output continues to ...
General-purpose DACs have applications in instrumentation, ...
Linear Technology demonstrates its latest measurement ...
10:29
Demos from Maxim Integrated at Electronica 2014 show ...
Bosch CEO Stefan Finkbeiner shows off latest combo and ...
STMicroelectronics demoed this simple gesture control ...
Keysight shows you what signals lurk in real-time at 510MHz ...
TE Connectivity's clear-plastic, full-size model car shows ...
Why culture makes Linear Tech a winner.
Recently formed Architects of Modern Power consortium ...
Specially modified Corvette C7 Stingray responds to ex Indy ...
Avago’s ACPL-K30T is the first solid-state driver qualified ...
NXP launches its line of multi-gate, multifunction, ...
Doug Bailey, VP of marketing at Power Integrations, gives a ...
See how to ease software bring-up with DesignWare IP ...
DesignWare IP Prototyping Kits enable fast software ...
This video explores the LT3086, a new member of our LDO+ ...
In today’s modern electronic systems, the need for power ...