Author Topic: Pixel Star for my Dad  (Read 3545 times)

Offline gadgetsmith

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Pixel Star for my Dad
« on: November 29, 2015, 06:09:24 AM »
My Dad has always had a star on the end of the house.  Last year is was complaining about how (his latest iteration) was falling apart.  As we were going down for Thanksgiving this year, I brought along a box of goodies, and using a piece of plywood he had lying around, made him a pixel star that was mounted to the chimney.

He, and my Mom are excited about the new addition.

100 ws2811 12v pixels driven by a RPi model B from a distance of about 50ft.  Had to use a buffer/line driver at this distance.




Offline JonB256

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Re: Pixel Star for my Dad
« Reply #1 on: November 29, 2015, 06:28:01 AM »

100 ws2811 12v pixels driven by a RPi model B from a distance of about 50ft.  Had to use a buffer/line driver at this distance.

Seeing these directly connected to a RPi and using a buffer/line driver - did you use Corey's uAmp driver or some other type?

I had not considered doing this because of the "level shifting" for the Data line (3.3v up to 5v) but wonder now if the uAmp would function as both signal conditioner and level shifter?  (would make a "wearable" RPi more doable, and maybe even the RPi Zero).

Offline gadgetsmith

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Re: Pixel Star for my Dad
« Reply #2 on: November 29, 2015, 07:02:06 AM »
Seeing these directly connected to a RPi and using a buffer/line driver - did you use Corey's uAmp driver or some other type?

I had not considered doing this because of the "level shifting" for the Data line (3.3v up to 5v) but wonder now if the uAmp would function as both signal conditioner and level shifter?  (would make a "wearable" RPi more doable, and maybe even the RPi Zero).

I used the buffer/line driver from RobG. http://diychristmas.org/vb1/showthread.php?4902-Buffer-line-driver-null-pixel-without-pixel-Group-Buy-1&highlight=buffer%2Fline

Just realizing how bad my cross posting is among the Christmas forums.  I posted this over at DIYC.com  300 pixels driven from a RPi B+ ; no line driver needed for short distances associated with "wearable" leds.

http://doityourselfchristmas.com/forums/showthread.php?40279-Neighbor-hooked-help-me-build-an-inexpensive-quot-starter-set-quot-%28300-pixels%29&p=398662#post398662

Made a Christmas Tree costume for my wife this year, but only used 50 pixel string, and she "wore" a RPi B+ with battery pack in a small bag around her waist.




Offline CaptainMurdoch

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Re: Pixel Star for my Dad
« Reply #3 on: November 29, 2015, 09:15:50 AM »
Nice implementation, thanks for posting.
-
Chris

Offline JonB256

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Re: Pixel Star for my Dad
« Reply #4 on: November 29, 2015, 08:27:55 PM »
I did go look at the recent manual update for Corey's uAmp (microAmp) board.

It definitely will do "level shifting" off of the RasPi to bring the lower voltage data signal (3.3v) up to the normal 5.0v used by virtually all 3 wire pixels.

I may need to buy a few RasPi Zero units. Their size would be perfect for a wearable, single string pixel project.

Quote
The uAmp is not "node specific" - it only clarifies, amplifies and re-transmits the data
fed to it. uAmp should be compatible with any single-ended (as opposed to differential)
0-5V signal. If a single-ended signal less than 5V is received, uAmp will retransmit the
signal amplified to a 5V level.

Perhaps sew on some individual WS2812b 5050 pixels since they already have the chip integrated into the back of a 5050 pixel.
« Last Edit: November 29, 2015, 08:39:34 PM by JonB256 »

Offline gadgetsmith

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Re: Pixel Star for my Dad
« Reply #5 on: November 30, 2015, 08:33:30 AM »
I did go look at the recent manual update for Corey's uAmp (microAmp) board.

It definitely will do "level shifting" off of the RasPi to bring the lower voltage data signal (3.3v) up to the normal 5.0v used by virtually all 3 wire pixels.

I may need to buy a few RasPi Zero units. Their size would be perfect for a wearable, single string pixel project.

Perhaps sew on some individual WS2812b 5050 pixels since they already have the chip integrated into the back of a 5050 pixel.


Oh yea, the uAmp would have worked well for my application as well, just had the others was all.  (purchased some when I also purchased RobG's RGB flood boards)  The biggest thing i've found in dealing with 5v vs. 12v pixels strings is that I can get a much further distance from controllers when using 5v strings.  As we know, 5v strings have voltage drop, which means using buck converters is necessary for long runs.  This year I changed over to 12v strings on my props that were more spread around; and while wiring became much more simplified, I ran into issues with being too far from the controller.  The buffer/line drivers fixed this, as i'm sure uAmp would have as well.  Only need to add them when control is an issue, as it was for this pixel star project.

The Pi Zero is really small, and think it would work well for a wearable application... unfortunately, they are very hard to find at the moment!  I've already seen a hack to hard wire a Edimax WiFi dongle right to the board to keep the package real small. 

http://hackaday.com/2015/11/28/first-raspberry-pi-zero-hack-piggy-back-wifi/

Offline JonB256

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Re: Pixel Star for my Dad
« Reply #6 on: November 30, 2015, 09:11:47 AM »

The Pi Zero is really small, and think it would work well for a wearable application... unfortunately, they are very hard to find at the moment!  I've already seen a hack to hard wire a Edimax WiFi dongle right to the board to keep the package real small. 

http://hackaday.com/2015/11/28/first-raspberry-pi-zero-hack-piggy-back-wifi/

This would be for a mid-year and Halloween project, so I'll find a few Zeroes by then.
I'm guessing since most battery packs (phone recharging type) put out "near" 5vdc, should I still add a buck converter to keep my voltage at a regulated 5vdc?

and, thanks for the WiFi hack link. I would be trying to keep this as thin as possible. I looked on EBay for loose WS2812b pixels and they are pretty cheap when you buy 200 or more. Would be fairly easy to attach to fabric to make wearable.

Offline gadgetsmith

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Re: Pixel Star for my Dad
« Reply #7 on: November 30, 2015, 01:18:12 PM »
This would be for a mid-year and Halloween project, so I'll find a few Zeroes by then.
I'm guessing since most battery packs (phone recharging type) put out "near" 5vdc, should I still add a buck converter to keep my voltage at a regulated 5vdc?

and, thanks for the WiFi hack link. I would be trying to keep this as thin as possible. I looked on EBay for loose WS2812b pixels and they are pretty cheap when you buy 200 or more. Would be fairly easy to attach to fabric to make wearable.

Ah, plenty of time for supplies to stabilize by then.

I used one of these batter packs for the Halloween costume.  http://www.amazon.com/gp/product/B00X5RV14Y?psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s00

Measuring the draw of a Pi B+ and a one minute repeating sequence (not full white), it took 821 mAh to run for 1.22 hrs; which if the battery truly lasted 20,100 mAh, would last for 29.7 hrs!  The B+ had no troubles running at the 5v, which measured ~4.95 - 5.1v during the times that I glanced at it during testing.  Did not stress test to the limits of the battery though, and the B+ is much more forgiving of voltage fluctuations than the B (which would randomly reboot if anything was plugged/unplugged from a USB port), so hopefully the zero has similar voltage setup as the B+.  Being a battery, it should be some nice clean power... i'd hope anyway, no telling what's under the hood!

Offline gadgetsmith

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Re: Pixel Star for my Dad
« Reply #8 on: January 03, 2016, 07:18:47 AM »
Well, this star setup ran from the day after thanksgiving to now without a hiccup!  When I was down to my folks after Christmas I was able to get into the Pi, but there was no active internet connection.  A reboot later and everything was back to normal, although I did not upgrade to 1.7, just stayed with 1.6/1.5... forget which one it was.

Have plans for next year and a mini-mega tree.  :)

Thanks again to the FPP crew!

Offline clydel

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Re: Pixel Star for my Dad
« Reply #9 on: March 04, 2016, 06:02:24 PM »
-sorry wrong thread :) -

 

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