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Re: Neopixel christmas lights

Posted: Wed Jan 11, 2017 10:44 am
by zoomx
racemaniac wrote:Also, not sure if it's mentioned on this forum already, but neopixels actually need about 3.7-3.8V to fully turn on all colors. Above that voltage you don't see any difference. The rest is just dissipated as heat by the voltage control on the pixel.

:shock:
Never heard about this.
The Adafuit PDF Datasheet
https://cdn-shop.adafruit.com/datasheets/WS2812.pdf
says 6-7V (instead of 5!!!)
but this one
https://www.parallax.com/sites/default/files/downloads/28085-WS2812B-RGB-LED-Datasheet.pdf
says +3.5~+5.3
but they are different chips so your're right for WS2812B, the first one is WS2812 without B.
Reading here
https://acrobotic.com/datasheets/WS2812B_VS_WS2812.pdf
WS2812 has four pins instead WS2812B has six pins so you can distinguish them. I believe that I have only WS2812B but I have to check.

I like very much these LEDs!

Re: Neopixel christmas lights

Posted: Wed Jan 11, 2017 10:57 am
by racemaniac
zoomx wrote:
racemaniac wrote:Also, not sure if it's mentioned on this forum already, but neopixels actually need about 3.7-3.8V to fully turn on all colors. Above that voltage you don't see any difference. The rest is just dissipated as heat by the voltage control on the pixel.

:shock:
Never heard about this.
The Adafuit PDF Datasheet
https://cdn-shop.adafruit.com/datasheets/WS2812.pdf
says 6-7V (instead of 5!!!)
but this one
https://www.parallax.com/sites/default/files/downloads/28085-WS2812B-RGB-LED-Datasheet.pdf
says +3.5~+5.3
but they are different chips so your're right for WS2812B, the first one is WS2812 without B.
Reading here
https://acrobotic.com/datasheets/WS2812B_VS_WS2812.pdf
WS2812 has four pins instead WS2812B has six pins so you can distinguish them. I believe that I have only WS2812B but I have to check.

I like very much these LEDs!

I also only ahve ws2812B, i indeed can't be sure how the others respond. the 2812b is also what you find most these days.

Re: Neopixel christmas lights

Posted: Wed Jan 11, 2017 7:26 pm
by RogerClark
Looking on the AliExpress listings, its hard to be sure which driver IC they are using.

Some vendors list both the B and non B versions in the description. I doubt they know what device is on the items they are selling, even if they list a specific IC.

I presume they all work in the same way, i.e as a bit shift register

Re: Neopixel christmas lights

Posted: Wed Jan 11, 2017 7:44 pm
by Rick Kimball
racemaniac wrote:I may be a bit late for this, but for the season i programmed some nice neopixel patterns to use as christmas lights :)...

Did you post the stm32 code you are using and I missed it?

Re: Neopixel christmas lights

Posted: Wed Jan 11, 2017 8:04 pm
by racemaniac
Rick Kimball wrote:
racemaniac wrote:I may be a bit late for this, but for the season i programmed some nice neopixel patterns to use as christmas lights :)...

Did you post the stm32 code you are using and I missed it?

haven't posted it yet
If you want to use it, here it is: http://users.telenet.be/racemaniac/Neopixel%20Xmas.zip
I hope it'll just work, i've used my spi dma library in it (since i'm now used to it). I don't think it relies on changes i made to the core locally, but not entirely sure.
If it doesn't work, just replace the SPI part :). I'm using the MOSI of SPI1 to generate the neopixel signal :). encoding 1 neopixel bit to 3 spi bits :).

And there's probably a bit of dutch here and there in the file :). It was a request of the girlfriend, and we also worked a bit on it together (learning here some programming & electronics basic ^^).

Re: Neopixel christmas lights

Posted: Wed Jan 11, 2017 8:24 pm
by Rick Kimball
thanks!

Re: Neopixel christmas lights

Posted: Thu Jan 12, 2017 8:46 am
by zoomx
RogerClark wrote:Looking on the AliExpress listings, its hard to be sure which driver IC they are using.

I believe that if the power source is rated as 5V they sell the B version. Maybe the older version is not selled any more or is difficult to find. But there is still a possibility so we have to check the power voltage.

@racemaniac,
thanks for sharing!

Re: Neopixel christmas lights

Posted: Mon Jan 16, 2017 5:42 pm
by racemaniac
Ok, after an appeal the video is back on youtube XD