Hello everybody. i'm working on a xmas tree project.

Hello everybody. i’m working on a xmas tree project. I’m planing to use an arduino uno that i already own, or teensy 3.1 (if delevired on time), and fastled. I’d like to make an animated star with a 144pixels/m WS2812B led strip like this one : http://www.aliexpress.com/item/144-LEDs-M-WS2812B-Chip-Black-PCB-WS2811-IC-Digital-5050-RGB-LED-Strip-Light-5V/1552767923.html. I’m thinking of using only 60 out of the 144 dots for the star illumination. Then 2x50 dots WS2811 LED pixel strings like this one : http://www.aliexpress.com/item/12mm-WS2811-as-WS2801-led-pixel-module-IP68-waterproof-DC5V-full-color-RGB-50pcs-a-string/1022672558.html. Could someone tell me if it’s possible to share the same Clock / Data lines with the 2 different strips. Both seems to be using the 3 wires design so it should all be WS2812B isn’t it ? Will I need to add a resistor on the CS line like explained for the better SPI devices tutorial here : http://hackaday.com/2014/11/25/better-spi-bus-design/.

I’m a bit confused about the desription of the 50 dots LED string. WS2801 controller, but the first line says WS2812B then WS2811…

I know WS2812B is now replaced by the APA102 design but as of now it seems it’s way more expensive thant the WS2812B and i couldn’t find the 50 dots LED pixels with the APA102

I’m a noob in the arduino / microcontroller world. Any help and clues would be greatly appreciated.

“I know WS2812B is now replaced by the APA102 design”

Two different companies. WorldSemi are the makers of the WS28xx series controller, the Shenzhen LED Color Opto-Electronic Co. makes the APA-series controllers.

One doesn’t replace the other - they are competitors.

The WS2812B is faster than the APA102 (800hz vs 400hz). They both mostly use the same 5050 RGB LED.

So, from a light and performance perspective, the WS2811/2812B IC is probably the higher-performing.

You are probably getting your info from some Chinese marketplace vendor - they aren’t noted for their attention to detail.

The WS2812B and WS2811 IC are very similar - both are 800Hz, but the WS2812B has some in-built protection against polarity reversal.

It’s better to get your info from the manufacturer or a reputable US/EU vendor, rather than from some online Chinese vendor whose sole motivation is to sell as much as they can. Typically they use any ‘buzzword’ they want to attract a buyer… I was looking for phenolic board today and so entered it in Aliexpress search engine - the first return was actually a lump of UHMW plastic, not a compressed and heat-set epoxy/fibre board. They just used the word ‘phenolic’ because they thought it indicated high-quality plastic. The same thing happens with LEDs - they use any buzzword they want - it doesn’t necessarily relate to the actual product.

APA102: http://upload.wikimedia.org/wikipedia/commons/c/c5/APA102_LED.pdf
WS2812B: http://www.adafruit.com/datasheets/WS2812B.pdf

If you are looking at a relatively straightforward implementation without difficult electrical or timing constraints, the WS2812B is a great choice.

The other thing to be sure of is what you are buying. If price is a consideration, don’t buy sealed waterproof strips - you are just buying stuff you don’t need. Get the bare board with sticky-backed adhesive. They are cheap and easy to work with.

Those LED strings are beefy - the board and LED is embedded in epoxy and they are quite big. But yes, it is possible to mix them with the WS2812* strips.

The second seller there ( the WS8211 string ) doesn’t have the highest ranking. Ray Wu’s store has them cheaper. http://www.aliexpress.com/store/product/50pcs-DC5V-12mm-WS2811-led-smart-pixel-node-with-all-color-wire-20AWG-IP68-rated/701799_1932874154.html … If you are only using 60 of the high-density strip why not use the cleaper 60/meter strips?

Not if you include shipping costs! Some shops ship for free.

@Mike_Thornbury - the APA102 datasheet is wrong - the APA102’s are MUCH faster than the WS2812’s. The WS2812’s have an 800Khz data rate and cap out at a 400Hz refresh rate, while the APA102’s have a 12-20Mhz (note the M not K) and a 19.2KHz refresh rate. See https://cpldcpu.wordpress.com/2014/08/27/apa102/ for more information (and I have personally verified the 12-20Mhz data rates).

As far as the leds that I personally am recommending to people when they ask me what to get, the APA102 has absolutely toppled the WS2812 in nearly all cases except for where cost of the leds is the primary concern.

Thanks @Daniel_Garcia , I rely on data sheets, I hate it when they get it wrong :frowning:

(And in case you think there’s some schizophrenia going on, there’s two different MT’s in this thread… Blame him, he named me!)

Ray wu store has a 16$ postage fee to my place. It would more than double the overall price of the item. I want the 144LED/m strip to stick on my tree topper Star. so i need the highest density possible. I’d like to build something similar to this : https://www.youtube.com/watch?v=7s9H6bZ_0zQ. Regards,

Thanks mike for confirmation that the 2 strips will be compatible on the same channel.

Where are you, Stephane? There are vendors that offer free shipping, as well as sellers in other countries than China.

Actually in Thailand. The 2 sellers of my 1st post offers worldwide free shipping.

We’re neighbours. I am in Brunei. I find it is swings and roundabouts - the cheapest sellers charge postage, the ones that offer freepost are more expensive. When I order, I buy for many projects at one time and amortise out the cost of the shipping that way. Buying one string at a time is always the most expensive.