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12v led strip data line with gpio?

PostPosted: Thu Mar 24, 2016 12:45 pm
by NandoEC
Hi all,
i am planning to control an addreseable rgb led strip (ws8211 ic, only three conexions 12+, gnd and data), it runs at 12v.
My plan is:
12v 3000mah battery power directly the leds.
same battery power the esp via voltage reductor. (as you can see, its for a wearable project)
feed data from esp to the leds via gpio... but that is the problem...
I read somewhere in the led strip specs, it need 70% of strip voltage to read the data line (8.4 v)
How can i step up the voltage from the gpio (3,3v i think) to at least 8-9v or even 12v so the data can flow?
I though some kind of mosfet, but i am having difficulties to find any 3.3v to 12v or so. And... will this be fast enough to control the addressable leds so i can make light patrons, etc. I am planning to use 5 meters long (15-18 feets)
My electronics knowledge is very, very limited.
Thank you

Re: 12v led strip data line with gpio?

PostPosted: Thu Mar 24, 2016 6:42 pm
by Barnabybear
Hi, the data line is 5V so 70% of that is 3.5V - from experience 3.3V works fine as every pixel regenerates the data at 5V anyway. If you want to be on the safe side you can up the ESP supply to 3.5 / 3.6V bu I've never needed to.

Re: 12v led strip data line with gpio?

PostPosted: Fri Mar 25, 2016 5:33 am
by NandoEC
Barnabybear wrote:Hi, the data line is 5V so 70% of that is 3.5V - from experience 3.3V works fine as every pixel regenerates the data at 5V anyway. If you want to be on the safe side you can up the ESP supply to 3.5 / 3.6V bu I've never needed to.



Yujuuuu!!! that simplifies a lot my plan.
Just power the leds, power the esp, and gpio conect to the led data input.
So only additional hardware needed is a step down regulator to conect the 12v from battery to the 3.3v pin of the esp.

Re: 12v led strip data line with gpio?

PostPosted: Fri Mar 25, 2016 6:07 am
by Barnabybear
NandoEC wrote:Yujuuuu!!! that simplifies a lot my plan.
Just power the leds, power the esp, and gpio conect to the led data input.
So only additional hardware needed is a step down regulator to conect the 12v from battery to the 3.3v pin of the esp.

Image
I used the BENQ12V-5V-3.3V, it's a bit heavy duty but as it will supply 2A @5V, I have the option to run 5V or 12V pixels with this from a 12V supply and it still fits in an 80 x 40 x 20 project box.
This is the one on my desk that I use for testing stuff.