Arduino Forum

Using Arduino => LEDs and Multiplexing => Topic started by: Zealot on May 14, 2015, 07:17 pm

Title: Lots of LEDs in series
Post by: Zealot on May 14, 2015, 07:17 pm
I have a general problem understanding how Neopixels work. I did read the Uberguide - but found no answer.

Having 10 LEDs, say 4V each, in series, I'd expect to need 40V.

How is it possible to drive 10, 20, 100, ... Neopixels with only 5V?
Title: Re: Lots of LEDs in series
Post by: ieee488 on May 14, 2015, 07:20 pm
A RGB LED is "essentially" 3 LEDs in parallel.

Not sure what you are asking.

Neopixels need to be powered by 5V.
Title: Re: Lots of LEDs in series
Post by: Zealot on May 14, 2015, 07:34 pm
A RGB LED is "essentially" 3 LEDs in parallel.

Not sure what you are asking.

Neopixels need to be powered by 5V.
I thought that this Neopixel rings, strips, ... connect the LEDs in series - hence my confusion.

Just found this image:
(http://www.adafruit.com/images/1200x900/1312-00.jpg)

Are all the Neopixels connected in parallel (not serial as I assumed)?


So basically a Neopixel strip looks like this?

(http://letsmakerobots.com/files/userpics/u1533/parallel_leds2.jpg)
Title: Re: Lots of LEDs in series
Post by: CrossRoads on May 14, 2015, 07:41 pm
A Neopixel is a controller and an RGB LED.
Each one has power, Gnd, Data In, Data Out.
Power passes thru (2 pins)
Gnd passes thru (2 pins)
Data In is an input (1 pin)
Data Out is output (1 pin)

So Power, Gnd are in parallel to all pixels, and Data is daisychained along.